Saw a few threads about flowing the TB out and am thinking about doing this at the moment... but is there anything else I can just bolt on in place of that? For my R31 skyline RB30 motor I could use a ZF fairlaine TB and just basically plug n play... but I was thinking maybe the 3.5L magnas share something in common with my 3.0L TR? Ill probably go buy a dremel today, I still have to clean the intake manifold heaps while it's off the car, so might as well port it out a bit while I'm at it.

People have been saying that opening the stock TB up more gives more throttle response... what about opening up the TB and the intake manifold? Would this give a significant increase in power? I have to replace two injectors too because they are cracked... I'm thinking about the basic principle where more air+fuel=power... but don't really want to take the heads off the car because I really couldn't be bothered since I am doing other things to it at the moment like spraypainting and have gutted the interior.

Edit: Just saw this thread... some are saying its 60mm and 65mm??? I'll go measure mine now.

http://www.aussiemagna.com/forums/showthread.php?t=4406&highlight=interchangable+throttle+body

Saw a few threads about flowing the TB out and am thinking about doing this at the moment... but is there anything else I can just bolt on in place of that? For my R31 skyline RB30 motor I could use a ZF fairlaine TB and just basically plug n play... but I was thinking maybe the 3.5L magnas share something in common with my 3.0L TR? Ill probably go buy a dremel today, I still have to clean the intake manifold heaps while it's off the car, so might as well port it out a bit while I'm at it.

People have been saying that opening the stock TB up more gives more throttle response... what about opening up the TB and the intake manifold? Would this give a significant increase in power? I have to replace two injectors too because they are cracked... I'm thinking about the basic principle where more air+fuel=power... but don't really want to take the heads off the car because I really couldn't be bothered since I am doing other things to it at the moment like spraypainting and have gutted the interior.

Edit: Just saw this thread... some are saying its 60mm and 65mm??? I'll go measure mine now.

http://www.aussiemagna.com/forums/showthread.php?t=4406&highlight=interchangable+throttle+body

I dont think ANY increase in throttle size gives more power or torque, and could probably hinder down low torque due to the lack of fly by wire control of opening the throttle.

The oversized units give the feel of more power simply because for the same amount of throttle as before, the new TB opens more. This could have been achieved by just putting your foot down a little more with the original throttle if you get what I mean?

I think you need to have a fairly tuned NA beast before the throttle plate increase is going to unleash any measurable amount of power.

Yea I know exactly what you mean...

I asked this in another thread also... but surely cleaning the intake system and porting it out would give me more power from the car? Also would extending the runner lengths by putting ra spacer plate in above the valley manifold just before the bottom of the intake runnes improve low end torque from longer runners? ...and if it improves lower end torque, would it take that out of higher end?

I have noticed that it has a crappy idle - 2000rpm take off, and then at about 2-3000rpm its ok, but it dies down until about 3500rpm where it goes hard until about 3800rpm sounding like an airy boring magna (Because I removed the air box and just run mesh over the AFM, which I'll swap for a pod when it goes all together again) and then from 3800rpm to about 5200rpm~ or around there it really hammers a nice deep throaty grunty exhaust tone, which then fades out to what sounds like the motor just wanting to rev till it blows up at about 6000rpm, then the auto four speed box will slam the next gear by itself.

I should really write a plan of what I want to achieve first, rather than working out what I can do... because I really want to make the car more lively off the line... it's just not fast enough 0-100. I have 205/65/R15's on the front which are brand new and even with the handbrake up its hard to spin them. People have said that turboing front wheel drives and making them go faster is worthless because they just spin... but my old rear wheel drives with power have just sat on the brake and spun in auto. Some of those were a 1990 VN Commodore 3.8L V6 Wagon which just stood on the brake... and a 1986 R31 Skyline which was 101kW at the rear wheels, both cars had 15's too.

I can't even spin the Magna tyres with the handbrake up! and the VN would probably have beaten my Magna stock to stock, and the Skyline surely would have too 0-100, but top end and from 90km/h the Magna would destroy both of them.

Maybe I should be looking to go for lower end torque from about idle - 3500rpm... still researching what else I can do though... will be an estimated 4-5 weeks until the TR is back on the road though... here is some mistubishi porn for yous for now... I painted the radiator support today after coating it in primer yesterday. I still have a coat to do on it.

Made my indicators into some clear flash ones and stuck up a picture of my big dirty port for viewing pleasure.

The largest restriction in the magna vehicles has always been the intake manifold plenum chamber design, not hte throttle body. Hence why RPW manafactured a new manifold design which most people have used.

I woudl suggest utilising this design for the best results from the car - retuning is not necessary but definitly recomend if you are going to use it.

http://www.rpw.com.au/shop/index.php?page=shop.product_details&flypage=shop.flypage&product_id=481&category_id=168&manufacturer_id=0&option=com_virtuemart&Itemid=31

Looking at that last picture there, that crap can be cleaned out with TB Cleaner, i used a whole can of it inside my plenium along with a bottlebrush, made a pretty good improvement with initial response, probably how it felt when it came outta the factory..

so i suggest that first:)

Gonna clean it out with a die grinder!

When I get motivated to get off my **** I'll catch a bus down the shops and buy one... sux having no wheels for the past month nearly, but it's ok. I'm not spending any money on fuel and spending it all on my Magna instead <3

Mitsiman: Could I achieve and increase in power by modifying the one I already have? In theory, more air + more fuel = more power... so how do we do this in an efi car? I thought basically a bigger TB would help it, but apparently it just gives more feel? Is that because we have to change the butterfly size for it to give more power?

So the runner sizes are ok? Because I think increasing the runner lengths would be no problem with a spacer plate... and after just examining the plenum size more, I can see why it's restrictive and small. Is there any way I can re-design the top third of the plenum to make it bigger without messing with the stable/safe operation of the motor? Also, what are the black plastic things for inside the plenum...

reason it gets all oily in there is from the oil return line from the tappet cover to the intake manifold. no sure what would happen if u put a little oil filter on the tappet cover and plugged the intake manifold. I know its an EPA issue but would it work?

The largest restriction in the magna vehicles has always been the intake manifold plenum chamber design, not hte throttle body. Hence why RPW manafactured a new manifold design which most people have used.

I woudl suggest utilising this design for the best results from the car - retuning is not necessary but definitly recomend if you are going to use it.

http://www.rpw.com.au/shop/index.php?page=shop.product_details&flypage=shop.flypage&product_id=481&category_id=168&manufacturer_id=0&option=com_virtuemart&Itemid=31


after looking at the link what is the difference between the twin TB or Single TB

Howdy Jase. The crank case ventilation system requires airflow, hence your idea might not work. But if u put an oil filter type of thing in-line, that might be a good idea to keep the inlet side clean.
Food for thought, actually.
Paint it red and say it's a Boost Accentuator with NOS Doser.....:D


reason it gets all oily in there is from the oil return line from the tappet cover to the intake manifold. no sure what would happen if u put a little oil filter on the tappet cover and plugged the intake manifold. I know its an EPA issue but would it work?

I got bored and started having a crack at the intake valley because I might replace it because where the fuel rail bolts in the thread on the manifold is stripped... I could use a nut and bolt instead of the right bolt so if it turns out ok, I'll try use it...

Still waiting for the front end to be sanded back into primer before I start putting the motor back together again and have to install new cambelt, and paint my radiator and gearbox oil cooler etc too... I painted the rad support yesterday with a final coat, and now just cleaning up the rest before I start putting it back together.

I sorta scratched it up a bit with some sandpaper... but I'll finish it all off with wet n dry and make it smooth as with no scratches eventually.

One thing I wanted to know is if having the ends of the ports curved out will mess with the gasket? Is there any way to use some other form of gasket that wont corrode other than paper? It's ok if it corrodes every six months or so, I dont mind pulling the car apart every so often lol... I have some high quality gasket roll which I bought which I was going to make gaskets with, but I'm not sure what exactly I'll do yet.

I wont be doing the heads if this works out to be a go'er... but I'll buy new heads and do it while the car is together. However now I will do the valley, maybe the plenum a bit also... the runners look pretty even all the way down, so not too much I can do about them... other than get new sized runners and make my own runners which are fatter and maybe even a bit shorter.

I'm still interested to find out what the black plastic things do inside the plenum, and what role they play because there is air that goes through a butterfly and air which seems like it doesnt, confusing.

ok so you've done your manifold, are u going to do the next piece in line? i doubt you'll gain anything cause you're not changing the pipe size.

a guy who builds and plays with engines once told me there isnt much point in port matching. what u want is for join to step from one to the other. make the next in line bigger than the piece before so there is no interference. does that make sense?

Eg: pipe is R20mm so make hole in the next flange R22mm so there is no interference

Thats a good theory, but still comes back to my question of whether different sized holes and ones which are curved at the tops will cause the gasket to leak.

Someone told me that it would... but I can't see how it would be much different to a normal gasket... except that there may be more pressure going towards the gasket compared to the standard one.

I wonder if there is a dodgy way of doing the top of my head intakes without removing the head... so they match up better. I could shove something in there, and then vacuum out all the crap and then remove whatever I put in there to block up the area.

Anyone?

Just to clarify, you're doing this to a SOHC 6G72 12v?

If so, what you're seeing in the intake plenum is the butterfly for the VICS (Variable Intake Control System). This lets the air run around the longer runners in the low revs for better low rpm torque, and then it switches to the short runners for mid-high rpms. I don't know how much of a difference it makes with or without this system, but that's what you'd have been looking at.

Yes, it's a SOHC 6G72 12v engine.

Thanks Killbilly... is this maybe why the car feels like crap up until about over 3000rpm also?