Just had a quick call from Graham regarding results of his flow tests.

As best as I can remember(he's emailing the full test results later) the stock 3.5/6G74 flowed about 226cfm, stock Ralliart 233cfm, and stock 380/6G75 277cfm.

Mildly modified 6G74 with filled inlet ports flowed 248cfm, fully modified with filled inlet ports and a days work on each cylinder(thats for in & ex ports and lower manifold) 257cfm.

Now get this; mildly modified 6G75 with filled inlet ports 299cfm!

As we predicted after inspecting the stock heads ex flows are ridiculously high. Can't remember the numbers but up to 0.300'' valve lift ex flow was over 80% of inlet and it went above 100% at low lifts. For a road engine you don't want more than 70%, and down near 65% is generally better. For a race engine about 75% is great and up to 80% usually doesn't hurt. Graham didn't cut the combustion chamber to unshroud around the ex valves and on the 6G74 flow was 199cfm.

Cheers,
Alan

This is good information Alan, thanks for sharing it with us.
So what is Graham's opinion on the Magna/380 head design in his experience? and did he mention what other modifications to the head would be considered next ?

Just had a quick call from Graham regarding results of his flow tests.

As best as I can remember(he's emailing the full test results later) the stock 3.5/6G74 flowed about 226cfm, stock Ralliart 233cfm, and stock 380/6G75 277cfm.
Mildly modified 6G74 with filled inlet ports flowed 238cfm, fully modified with filled inlet ports and a days work on each cylinder(thats for in & ex ports and lower manifold) 257cfm.


Alan

Those figures ive highlighted are way different to the stock, ralliart and then my ported heads flow figures.

Much like the comp ratio Graham said that pajero pistons and SOHC heads gives.

Those figures ive highlighted are way different to the stock, ralliart and then my ported heads flow figures.

Much like the comp ratio Graham said that pajero pistons and SOHC heads gives.

So what are your figures Jason? What depression did you flow at?

Cheers,
Alan

So what are your figures Jason? What depression did you flow at?

Cheers,
Alan

See i dont normally splash my findings up on forums but i will tell you that the ralliarts i flowed had 265.38 cfm on the inlets and 204 cfm on the exhausts with a In/EX % of 76.87.

And yes the exhaust was flowing 81% of the inlets @.300" lift

They were flowed on a Pro-Flo cylinder head machince

See i dont normally splash my findings up on forums but i will tell you that the ralliarts i flowed had 265.38 cfm on the inlets and 204 cfm on the exhausts with a In/EX % of 76.87.

And yes the exhaust was flowing 81% of the inlets @.300" lift

They were flowed on a Pro-Flo cylinder head machince

At what depression? and did you have in & ex manifold connected? Were they stock Ralliart?

Cheers,
Alan

At what depression? and did you have in & ex manifold connected? Were they stock Ralliart?

Cheers,
Alan

Depression i cant remember (Maybe i have depression LOL. its not on my flowsheets infront of me).

Yes they were brand new ralliart castings. They were the base heads that i used for my big hp engine. lower inlet and a stock cast exhaust manifold were attached

Depression i cant remember (Maybe i have depression LOL. its not on my flowsheets infront of me).

Yes they were brand new ralliart castings. They were the base heads that i used for my big hp engine. lower inlet and a stock cast exhaust manifold were attached

OK flow numbers mean little without knowing what depression they were obtained at. Higher depression raises the CFM reading. Also the figures need to be corrected for air temp.

Cheers,
Alan

OK flow numbers mean little without knowing what depression they were obtained at. Higher depression raises the CFM reading. Also the figures need to be corrected for air temp.

Cheers,
Alan

Basically what ur saying is comparing head flow CFM is like comparing dyno HP figures...... each and every dyno will have variences same with flowbenchs.

The guy who flows my heads has been building race engines for over 20yrs. He now builds a lot of drift engines here in SA and GTVi (Bill) will know who im talking about and how well his drift cars go.

His flow bench is in a climate controlled room.

All i can say is there is no issues with any of the heads ive done and theres no problems with my HP outputs either (especially considering the current donkey engine is running Tighe crap cams of debateable quaility).

OK flow numbers mean little without knowing what depression they were obtained at. Higher depression raises the CFM reading. Also the figures need to be corrected for air temp.

Cheers,
Alan

Which also raises my curiosity, how many "inches of water" were your numbers calculated?

Which also raises my curiosity, how many "inches of water" were your numbers calculated?

About 8" raised up before the :beer: kicked in. LOL

Sorry back on topic now.

About 8" raised up before the :beer: kicked in. LOL

Sorry back on topic now.

:bowrofl:


On topic:
Alan J, who took those photos? Are they of the actual bench flow test, or samples to show what equipment was used?

Alan what lift and depression are these readings? Looks like 28'' but what lift. Did Graham test the rest of the intake system to see of any static restrictions. Good work Graham for doing a 74/75 comparison, I'm guilty for not finding the time.

Cheers Dave

Just had a quick call from Graham regarding results of his flow tests.

As best as I can remember(he's emailing the full test results later) the stock 3.5/6G74 flowed about 226cfm, stock Ralliart 233cfm, and stock 380/6G75 277cfm.

Mildly modified 6G74 with filled inlet ports flowed 238cfm, fully modified with filled inlet ports and a days work on each cylinder(thats for in & ex ports and lower manifold) 257cfm.

Now get this; mildly modified 6G75 with filled inlet ports 299cfm!

As we predicted after inspecting the stock heads ex flows are ridiculously high. Can't remember the numbers but up to 0.300'' valve lift ex flow was over 80% of inlet and it went above 100% at low lifts. For a road engine you don't want more than 70%, and down near 65% is generally better. For a race engine about 75% is great and up to 80% usually doesn't hurt. Graham didn't cut the combustion chamber to unshroud around the ex valves and on the 6G74 flow was 199cfm.

Cheers,
Alan
If these flow results are at 28" W.G. then ultimate power is not really being hampered by the cylinder head.
According to the 0.256 X CFM X 6 conversion formula for a 6 cylinder to find out the potential horsepower then the base engine "could" be persuaded to produce 347 HP / 259 KW!!
Gerry

If these flow results are at 28" W.G. then ultimate power is not really being hampered by the cylinder head.
According to the 0.256 X CFM X 6 conversion formula for a 6 cylinder to find out the potential horsepower then the base engine "could" be persuaded to produce 347 HP / 259 KW!!
Gerry

Yep. When i flowed the stock ralliart heads i had they showed a potential horsepower figure of 386HP, well thats what the flowbench computer program worked it out to.

Please see attached sheets for the flow figures I have for a standard set of 6G74 heads. Also attached is the after results of what I would call an extensive porting job.

:lurk:

Sorry I had to rush off to Joberg last week for post race testing and have just back in. So hope I haven't missed answering any of your questions.

Yes flowbench tests are like dynos. Lots of ways to fudge the numbers or misunderstand the numbers. So many standards and test methods, plus many benches are seldom if ever recalibrated. Consequently the numbers really only relate to that particular bench unless they are a certified bench.

On top of that the flow changes according to the size of the bore adapter, the type of spark plug and how far it is screwed into the head. Also if its a manual bench you have to know how to calculate the flow and not put the wrong numbers into the calculator.

The photos are of the actual bench with one of Graham's heads fitted. Tests were done with stock cast ex manifold and stock lower inlet manifold(filled head ports had matching filled manifold ports).

The comparison chart and comments came through from Graham while I was away so I haven't had time to fully digest them but on the surface look very impressive for the 380 head. Remember though that flow numbers are just an indication. They are useful but just a tuning tool. Graham doesn't take much notice of flow numbers other than to gauge where there are weaknesses, and for inlet to ex flow ratio for balancing out inlet and ex cam lobe profiles. He never chases flow, always his concern is mixture preparation and burn quality.

He included the Cosworth GAA head numbers for comparison with the 6G75. To give some background. The Cosworth ruled the tracks 30 years ago. Cosworth quoted the stock engine with mechanical fuel injection and mechanical ignition at 440HP minimum in Group 2 trim. They were always very conservative in quoted HP figures. The car I worked on never had less than 482HP with slide throttles(not permitted in Gp2). In endurance car trim for 24hr races they weighed nearly 1700kg but would accelerate to 100 in 3.4-3.6 sec and top 300kph with Nurburgring gearing. About 1977-79 they were allowed into F5000 open wheelers but had to be toned down so as not embarrass the 5ltr pushrod Chevs and Fords. Cosworth produced a special F5000 kit with butterfly throttles and milder EA1 inlet cam. These made 460HP minimum and 300 lb/ft torque. Graham has just done a GAA for historic and as you can see the lightly modified 380 outflowed the GAA.

Graham also said even in stock the 380 outflowed ported JRM(Jawa) speedway heads and he has been working with Yamaha to get the 450 head working. The 5 valve head with 28mm inlets stalled at 240cfm. With a few of Graham's tricks he got it up to 252.

Cheers,
Alan

Cheers Alan, thanks for the data very enlightening. I'm not sure I'd want to rev that Y aluminium exhaust rocker as hard as a GAA Cosworth could go though but the crossover intake would look neat on a 6G75 anyway . Excellent work and thanks again for shareing.

Cheers Dave.

Cheers Alan, thanks for the data very enlightening. I'm not sure I'd want to rev that Y aluminium exhaust rocker as hard as a GAA Cosworth could go though but the crossover intake would look neat on a 6G75 anyway . Excellent work and thanks again for shareing.

Cheers Dave.


Yes Dave back then the way to get HP meant more rpm. With advanced tuning methods, particularly electronic injection and engine management, I think the same HP could have been achieved perhaps below 8,000rpm. The Cosworth GAA had monster cams. A lot wilder than their F1 engines! The DA12 inlet had 59/83 seat timing, 0.460" lift and 273 deg duration @ 0.050", and the DA10 ex was 78/54 timing, 0.410" lift and 256 deg duration @ 0.050".

In some ways the 380/3.8 chamber is a lot nicer than the Cosworth. I'm not sure why Mike Hall was allowed to get it through Cosworth approval with inlet valve crowding. The valves didn't need to be so close as the engine had a 100mm bore and by todays standards relatively small 37.2mm valves (later increased to 38.6mm. In todays engines designers would be aiming for 41-42mm on 100mm bore. The Ducati 1098R running World Superbike has 44.3mm inlets over a 106mm bore). There is good separation between the 380/6G75 valves and that helps get the high lift flow up with little work(same thing helps the 6G74 get good flow too in spite of tiny valves).

The 6G75 combustion chamber is a lot deeper than GAA though due to wider valve angles and this would mean a big lump on the piston to get the compression up and would hurt the burn and add weight. Built as an endurance engine the GAA had only 11.5:1 comp ratio incidentally.

We originally reckoned the 6G75 as a race engine was good for around 450HP @ 7500rpm without a lot of work. Graham hadn't had a 380 head on the flow bench then so we were only guessing, but the head reminded us both of the GAA at the time. As you mention valve gear would likely be the main issue but the head should work well enough to allow a fairly non-aggressive approach to cams. Did you have any rocker failures during endurance testing?

On your last point about sharing information, both Graham and I have no issues with sharing knowledge and it irritates us that quite a few think they have secrets worth keeping. Not always, but often this just shows their immature understanding of tuning. Of themselves numbers, whether they be related to cams, head flow, compression ratio, HP etc., are fairly meaningless. Unfortunately so many have been hoodwinked to think a 280 deg cam must be better than a 270, 250 cfm flow must be better than 230, 11:1 comp ratio must be better than 10:1, and so on.

Some of the young guys wouldn't know what a GAA engine is so I've included a photo with ladder bar between the damper towers removed and air box removed (sprint engines often didn't run an air box but for Nurburgring 1000km and Le Mans and Spa 24 hrs a box and filter was used) to expose the goodies. Yes the crossover manifold still looks the goods. This is only a Gp 2 butterfly manifold, not the big HP slide job. Would be a nice bit of kit for a street engine too. Easy 335HP with mild cams for 6G75!

Cheers,
Alan

Amazing information, very well done and I commend the givers of the information for their willingness to share. Very impressed and will result in 6G7# being lifted another level. With some boost engines like this will prove extremely difficult to beat :D

Yes Dave back then the way to get HP meant more rpm. With advanced tuning methods, particularly electronic injection and engine management, I think the same HP could have been achieved perhaps below 8,000rpm. The Cosworth GAA had monster cams. A lot wilder than their F1 engines! The DA12 inlet had 59/83 seat timing, 0.460" lift and 273 deg duration @ 0.050", and the DA10 ex was 78/54 timing, 0.410" lift and 256 deg duration @ 0.050".

In some ways the 380/3.8 chamber is a lot nicer than the Cosworth. I'm not sure why Mike Hall was allowed to get it through Cosworth approval with inlet valve crowding. The valves didn't need to be so close as the engine had a 100mm bore and by todays standards relatively small 37.2mm valves (later increased to 38.6mm. In todays engines designers would be aiming for 41-42mm on 100mm bore. The Ducati 1098R running World Superbike has 44.3mm inlets over a 106mm bore). There is good separation between the 380/6G75 valves and that helps get the high lift flow up with little work(same thing helps the 6G74 get good flow too in spite of tiny valves).

The 6G75 combustion chamber is a lot deeper than GAA though due to wider valve angles and this would mean a big lump on the piston to get the compression up and would hurt the burn and add weight. Built as an endurance engine the GAA had only 11.5:1 comp ratio incidentally.

We originally reckoned the 6G75 as a race engine was good for around 450HP @ 7500rpm without a lot of work. Graham hadn't had a 380 head on the flow bench then so we were only guessing, but the head reminded us both of the GAA at the time. As you mention valve gear would likely be the main issue but the head should work well enough to allow a fairly non-aggressive approach to cams. Did you have any rocker failures during endurance testing?

On your last point about sharing information, both Graham and I have no issues with sharing knowledge and it irritates us that quite a few think they have secrets worth keeping. Not always, but often this just shows their immature understanding of tuning. Of themselves numbers, whether they be related to cams, head flow, compression ratio, HP etc., are fairly meaningless. Unfortunately so many have been hoodwinked to think a 280 deg cam must be better than a 270, 250 cfm flow must be better than 230, 11:1 comp ratio must be better than 10:1, and so on.

Some of the young guys wouldn't know what a GAA engine is so I've included a photo with ladder bar between the damper towers removed and air box removed (sprint engines often didn't run an air box but for Nurburgring 1000km and Le Mans and Spa 24 hrs a box and filter was used) to expose the goodies. Yes the crossover manifold still looks the goods. This is only a Gp 2 butterfly manifold, not the big HP slide job. Would be a nice bit of kit for a street engine too. Easy 335HP with mild cams for 6G75!

Cheers,
Alan

Alan,

I take it your having a dig at me??? :wtf:

Well if you are then i couldnt care less, i have always done things my way and i seem to have got the results i wanted for minimal cash outlay which is how i wanted to do things all along. :tired:

Anyway i'll stay in my corner now :iough:

Alan, never had a 3.8 break a rocker arm in testing but they didn't get reved over 7100 in testing.
Forgot about the lifter thing all I know is the lifter has about 2.5mm of travel and the lash limits are 1.3mm max .5mm minimum. Thats checked with a dail indicator on the end of the rocker arm above the lifter then collapse the lifter with a pin to check the amount of lash. So yeah they have alot of lifter preload standard but thats al I know sorry.

Cheers Dave

Alan, never had a 3.8 break a rocker arm in testing but they didn't get reved over 7100 in testing.
Forgot about the lifter thing all I know is the lifter has about 2.5mm of travel and the lash limits are 1.3mm max .5mm minimum. Thats checked with a dail indicator on the end of the rocker arm above the lifter then collapse the lifter with a pin to check the amount of lash. So yeah they have alot of lifter preload standard but thats al I know sorry.

Cheers Dave

OK thanks for that Dave. I''l pass it on to Graham. His valve springs are lighter than stock and with completely different harmonic qualities so will stress the rockers less. However the extra lift and accompanying geometry changes can alter the situation too by adding loads in different areas along the rocker that weren't accounted for during pre-production R & D.


Cheers,
Alan

Some of the young guys wouldn't know what a GAA engine is so I've included a photo with ladder bar between the damper towers removed and air box removed (sprint engines often didn't run an air box but for Nurburgring 1000km and Le Mans and Spa 24 hrs a box and filter was used) to expose the goodies. Yes the crossover manifold still looks the goods. This is only a Gp 2 butterfly manifold, not the big HP slide job. Would be a nice bit of kit for a street engine too. Easy 335HP with mild cams for 6G75!

Cheers,
Alan

Awesome looking TB's!!!

Bit off topic:
Back in the UK the Family2 GM engines got a lot of attention from the motoring circles, particularly from Westfield and Caterham fans running individual tapered TB's on the 16XE/20XE blocks. 292BHP from a 2.0 4 cyl NA shows how good the Cosworth COSCAST heads were on the them. http://www.sbdev.co.uk/Main.htm

It is even possible to get 240bhp from a tiny 1.6 4cyl: http://www.sbdev.co.uk/Taper%20Kits/New%201.6L%20Taper%20Kits/1.6L%20TP%20kit%20top%20of%20the%20range/1.6L%20TP%20kit%20top%20of%20the%20range.htm

Alan,

I take it your having a dig at me??? :wtf:

Well if you are then i couldnt care less, i have always done things my way and i seem to have got the results i wanted for minimal cash outlay which is how i wanted to do things all along. :tired:

Anyway i'll stay in my corner now :iough:

Jason I wasn't specifically having a dig at anyone, just saying what I feel about so-called secret information.

Very fortunately many have a more noble outlook.

Just to cite a few notable examples:

The motorsport engineering base in and around Melbourne is due mainly to Repco and its engineers who willingly passed on what they learned. In fact Repco spent a lot of money using its bright people to help educate others. During the Repco Brabham campaign they took John Judd on board and mainly under the influence of Phil Irving he learned the "secrets" that skilled him up to later develop and build F1 engines himself, and hes still building world class engines today.

George Wade started out at Repco and developed the Repco cam grinder. I don't think he got a cent for it and later had to pay for all the grinders he got off Repco, but where would cam grinding have been in Australia without the Repco cam grinder if George Wade had kept his knowledge secret? Not to mention the world class skills George taught people about cam tech while they worked for him.

Then you had Merv Waggott in Sydney. He was manufacturing world class 1600 and 2 ltr race engines that were beating the Cosworths, all in his own workshop. He willingly passed on his "secrets" to Graham Bell and others, and as we all know as Graham developed his skills he freely passed what he learned through his books over the last 30 yrs. Many race mechanics and engineers cut their teeth on those books and probably don't have a clue how much they owe Merv freely disclosing his "secrets".

The same applies overseas. In the UK Ford contracted Keith Duckworth to build a F1 engine. The Cosworth FVA and then DFV resulted. This was first time a 4 valve engine worked, by then the idea had been around 55yrs. Did Ford or Cosworth keep the knowledge "secret"? You know the answer, every manufacturer has a 4 valve based on the original Duckworth design and they don't pay Ford or Cosworth a cent in licence fees. As Cosworth expanded they went on to train up dozens of people with their "secrets" and many later went on to be engine manufacturers; Brian Hart (Hart) and Mario Illien (Illmore-Mrecedes) being two going on to manufacture F1 engines.

In USA there was Harvey Crane. With a couple of exceptions he probably taught most American cam grinders his "secrets". Like George Wade he needed a decent cam grinder so went to Italy to show Berco how to build one. He never got a cent but came away with grinders that were capable of grinding accurate lobes, lobe after lobe. Harvey developed the idea of measuring lobe duration @ 0.050". He introduced the word "cam intensity" into our vocabulary (later stolen by Comp Cams) and developed a roller follower that would hold together. Many of these names won't mean much here in Aust but in USA names like John Reed(famous for Reed NASCAR cams), Joe Luanti (Luanti cams), Harold Brookshire (UltraDyne cams also developed Luanti VooDoo cam profiles and Comp Cams High Energy cam profiles), Tom Woitesek (Comp Cams), Ronnie Weir (Race Cams), Mark Heffington (Cam Dynamics), plus others I've forgotten all learned their craft form Harvey freely passing on his "secrets".

Thats just for starters. How about in the medical profession. Where would we be if surgeons kept skills and techniques to themselves?

Cheers,
Alan

Thats just for starters. How about in the medical profession. Where would we be if surgeons kept skills and techniques to themselves?

Cheers,
Alan

Good analogy, we'd be dead :roflwtf:

Jason I wasn't specifically having a dig at anyone, just saying what I feel about so-called secret information.

Very fortunately many have a more noble outlook.

Just to cite a few notable examples:

The motorsport engineering base in and around Melbourne is due mainly to Repco and its engineers who willingly passed on what they learned. In fact Repco spent a lot of money using its bright people to help educate others. During the Repco Brabham campaign they took John Judd on board and mainly under the influence of Phil Irving he learned the "secrets" that skilled him up to later develop and build F1 engines himself, and hes still building world class engines today.

George Wade started out at Repco and developed the Repco cam grinder. I don't think he got a cent for it and later had to pay for all the grinders he got off Repco, but where would cam grinding have been in Australia without the Repco cam grinder if George Wade had kept his knowledge secret? Not to mention the world class skills George taught people about cam tech while they worked for him.

Then you had Merv Waggott in Sydney. He was manufacturing world class 1600 and 2 ltr race engines that were beating the Cosworths, all in his own workshop. He willingly passed on his "secrets" to Graham Bell and others, and as we all know as Graham developed his skills he freely passed what he learned through his books over the last 30 yrs. Many race mechanics and engineers cut their teeth on those books and probably don't have a clue how much they owe Merv freely disclosing his "secrets".

The same applies overseas. In the UK Ford contracted Keith Duckworth to build a F1 engine. The Cosworth FVA and then DFV resulted. This was first time a 4 valve engine worked, by then the idea had been around 55yrs. Did Ford or Cosworth keep the knowledge "secret"? You know the answer, every manufacturer has a 4 valve based on the original Duckworth design and they don't pay Ford or Cosworth a cent in licence fees. As Cosworth expanded they went on to train up dozens of people with their "secrets" and many later went on to be engine manufacturers; Brian Hart (Hart) and Mario Illien (Illmore-Mrecedes) being two going on to manufacture F1 engines.

In USA there was Harvey Crane. With a couple of exceptions he probably taught most American cam grinders his "secrets". Like George Wade he needed a decent cam grinder so went to Italy to show Berco how to build one. He never got a cent but came away with grinders that were capable of grinding accurate lobes, lobe after lobe. Harvey developed the idea of measuring lobe duration @ 0.050". He introduced the word "cam intensity" into our vocabulary (later stolen by Comp Cams) and developed a roller follower that would hold together. Many of these names won't mean much here in Aust but in USA names like John Reed(famous for Reed NASCAR cams), Joe Luanti (Luanti cams), Harold Brookshire (UltraDyne cams also developed Luanti VooDoo cam profiles and Comp Cams High Energy cam profiles), Tom Woitesek (Comp Cams), Ronnie Weir (Race Cams), Mark Heffington (Cam Dynamics), plus others I've forgotten all learned their craft form Harvey freely passing on his "secrets".

Thats just for starters. How about in the medical profession. Where would we be if surgeons kept skills and techniques to themselves?

Cheers,
Alan


Medical profession is alot different ************************************************** ***************************engine.

See those people you have spoken about above all get PAYED (by there emloyeer or through sales or similar) for there research and "onsell" of information and/or education of others....Whereas i get zilch, zero, zip from anyone for all my hard work, hence why i keep my some of my cards close to my chest.

Im sure you can see my point?

So lets agree to disagree on the whole magna subject.

Oh and yes i have contacts within automotive "aftermarket" industry that have helped me with alot of technical info BUT they had to do it on the quiet..... Why? because im a small player in a large field, who offers no monitary advantage to the companies that they represent.

Medical profession is alot ++++++++++++++++++++++++++++++++++++++with a cars engine.

See those people you have spoken about above all get PAYED (by there emloyeer or through sales or similar) for there research and "onsell" of information and/or education of others....Whereas i get zilch, zero, zip from anyone for all my hard work, hence why i keep my some of my cards close to my chest.

Im sure you can see my point?

So lets agree to disagree on the whole magna subject.

Oh and yes i have contacts within automotive "aftermarket" industry that have helped me with alot of technical info BUT they had to do it on the quiet..... Why? because im a small player in a large field, who offers no monitary advantage to the companies that they represent.

Thats the point Jason, they weren't paid. They gave of themselves freely, and at times considerable personal cost because they wanted to be helpful. In fact many they helped later became their competitors.

Cheers,
Alan

Thats the point Jason, they weren't paid. They gave of themselves freely, and at times considerable personal cost because they wanted to be helpful. In fact many they helped later became their competitors.

Cheers,
Alan

I find that hard to believe, theres always kick backs and payment of sorts when you are employed by a company/business. I know me when i was in R&D there was somethings that were "let out or leaked" but the full details and inner workings were kept very hush hush, and we were all made to sign a confidentiality contract.

Anyway i have nothing more to say other than be aware of dreamers/tyrekickers..... theres lots out there (as ive found out over the years)

Well unless you're a business and have financial gain by withholding information from a competitive point of view, what exactly can you loose by sharing said information if it's going to help the development of better performance?

Graham has just sent flow numbers for his finalised 6G74 porting. This is still a light port job and extensive fill as for the prototypes but with a simple tweak in the bowl area that took only another 10 mins per port he was able to get better flow right through the lift range than with the heavily ported prototype. When he gets a bit of time he will try some more tweaks to the 3.8 6G75 heads too.

Cheers,
Alan

Alan, Graham,
Fantastic results. You are effectively suggesting that with this type of head work, improve the exhaust, cams and a sensible ECU tune that it will be very easy to achieve much better than the Ralliart 180KW.


Keep up the good work!!

Next to hear about the magic cams!!

Gerry

Here are pics of the heads and lower manifold as now fitted to Graham's AWD.

Cheers,
Alan

Hi Alan, some pic's of the modified inlet ports would be interesting, if possible...thanks!

Thanks for the pics Alan, less typing involved when you post a pic. Graham's getting some work done, keep it up guys.

Cheers Dave

Anyway i have nothing more to say other than be aware of dreamers/tyrekickers..... theres lots out there (as ive found out over the years)

I am a dreamer tyre kicker LOL

Jason I can totally understand both sides of the ledger

I probably would have PM'd Alan with the figures so you still had that sense of privacy from all your hard work

I have NFI about all these cams and stuff but it makes for great reading

Keep up the AWESOME WORK FELLAS :woot:

FROM A TYRE KICKER :facejump:

Hi Alan, some pic's of the modified inlet ports would be interesting, if possible...thanks!

Sorry those posted are the only pics I have. The second pic is of the inlet ports.

Cheers,
Alan

Sorry those posted are the only pics I have. The second pic is of the inlet ports.

Cheers,
Alan

No worries Alan, just trying to grasp the filling part of the inlets.

No worries Alan, just trying to grasp the filling part of the inlets.


In the heads the filling extended along the outside wall to just past where the center divider begins. Before the divider the port is too big but after it goes into two its actually too small.

In the lower manifold the fill extends all the way back to the sharp bend.

Cheers,
Alan

Ok great, i can see what you mean....thanks for that mate.

Here are pics of the heads and lower manifold as now fitted to Graham's AWD.

Cheers,
Alan

Are those a ported Magna heads or 380 heads?

Are those a ported Magna heads or 380 heads?

Those photos are of Magna 6g74 heads.

Graham has just done another prototype 380 port job and I will get numbers up as soon as he sends them to me.

Cheers,
Alan

Great! I'm wondering if the 380 intake ports are anything like the US 6G75 Mivec.

Those photos are of Magna 6g74 heads.

Graham has just done another prototype 380 port job and I will get numbers up as soon as he sends them to me.

Cheers,
Alan
I would REALLY like to see these!!:bouncin:

These are the latest 380 flow numbers. From the list Graham has done 3 different specs and the last effort has given good increases at all lifts. The comparison with the Cosworth GAA head show how well the 380 flows with very little work even though the inlet valves are relatively small. They aren't as limiting as the tiny valves in 3.0/3.5 ltr heads but still a bit small. In a race head done with a good budget you would probably use at least 38mm before there was a shrouding issue. The primary inlet ports and lower manifold were filled too just like on the 3.5 heads.

Cheers,
Alan

They're huge gains! Kicking myself I didn't get a 380 motor or at least the heads for my FI build. Might do it yet....

Time to give the man a call.

Alan, did you just test the one cam profile? I thought Graham had upto 4 profiles he was getting ground?

They're huge gains! Kicking myself I didn't get a 380 motor or at least the heads for my FI build. Might do it yet....

Time to give the man a call.

Alan, did you just test the one cam profile? I thought Graham had upto 4 profiles he was getting ground?

He originally had been talking about several profiles but had forgotten that the Magna needed different masters done for the front bank. That doubled costs and Graham got sidetracked buying a 3.8 engine and by what might be possible with the 3.8 engine. He is again talking about the possibility of a track day cam but it will be well into the future as he has to get a bit back into the bank from the development cost to date.

Cheers,
Alan

These are the latest 380 flow numbers. From the list Graham has done 3 different specs and the last effort has given good increases at all lifts. The comparison with the Cosworth GAA head show how well the 380 flows with very little work even though the inlet valves are relatively small. They aren't as limiting as the tiny valves in 3.0/3.5 ltr heads but still a bit small. In a race head done with a good budget you would probably use at least 38mm before there was a shrouding issue. The primary inlet ports and lower manifold were filled too just like on the 3.5 heads.

Cheers,
Alan
I hope that I can get my grubby little hands on one of these in the future!!

Great! I'm wondering if the 380 intake ports are anything like the US 6G75 Mivec.


No they aren't. The MIVEC primary ports are far too big and so are those in the 380/Galant/Pajero 6G75 so Graham closes them down. The ports in his modified 380 heads and lower inlet manifold are filled in to the same size as in his modified 3.5 heads. When Graham send me pictures I'll post them up.

Just highlights that the major flow restriction most heads in the last 20 years is the valve head and the area 20-25mm either side of the valve seat. Except at big valve lifts, which road cams won't reach anyway, small ports help air flow and engine/throttle response. 300cfm at 0.500" lift with a basic rework isn't too shabby though given there wasn't any flow loss at lower lifts.

Cheers,
Alan

No they aren't. The MIVEC primary ports are far too big and so are those in the 380/Galant/Pajero 6G75 so Graham closes them down. The ports in his modified 380 heads and lower inlet manifold are filled in to the same size as in his modified 3.5 heads. When Graham send me pictures I'll post them up.

Just highlights that the major flow restriction most heads in the last 20 years is the valve head and the area 20-25mm either side of the valve seat. Except at big valve lifts, which road cams won't reach anyway, small ports help air flow and engine/throttle response. 300cfm at 0.500" lift with a basic rework isn't too shabby though given there wasn't any flow loss at lower lifts.

Cheers,
Alan

Alan, do you think this same port modification would still be applicable to a Supercharged 380 engine or would it need the larger ports for extra breathing?

Alan, do you think this same port modification would still be applicable to a Supercharged 380 engine or would it need the larger ports for extra breathing?

No I don't think there would be any large need with a blower engine, turbo would benefit though. Filling ports when blown/turboed is a lot more difficult and expensive as the air charge is so much hotter. Without really effective intercooling air temp can go higher than the recommended 120-140 deg C of epoxy fillers. That means welding or else screwing in moulded cast aluminium "stuffers". Stuffers work well but you have to be doing enough heads to make casting them economical.

The fallacy has been that big ports help breathing. They don't. The major restriction is always the valve head and the wall of the combustion chamber and cylinder. The best design head with the best relationship between valve size, cylinder size, port angle to valve, port angle to cylinder etc etc to maximise flow past the entire circumference of the valve head requires a port only 0.84 of valve dia. Thats what you'll find only in purpose built/designed race engines. So if the port goes bigger than 0.84 high lift flow won't improve, in fact it will likely fall because of turbulence, and low lift flow will be especially poor. Most engines don't need or want more than 0.82. Thats OK for a 2 valve engine but is generally too big for good mid-range power in a 4 valver. There something closer to 0.75-0.78 is best. What is important is the inlet flow at 60-65% cam lift and ex flow at 70-75%. Get the flow rate up there, without losing it at lower lifts, and you're on your way to making a nice engine.

Cheers,
Alan