howdy,

just curious to when a 3 inch exhaust system is more efficent than a 2½ inch exhaust system. i know when u start making more power u get a bigger exhaust so when is it a good idea to go from a 2½ to a 3?

well according to rpw, for a magna either system is fine, no loss or gains, the 3in sounds louder

yeah, not after more sound just chasing the power and trying to figure out what will work better. say the engine gets another 30kw and bumps up to 190kw at the wheels, then what?

well according to rpw, for a magna either system is fine, no loss or gains, the 3in sounds louder

Not exactly........... I think you'll find RPW only 'claim' a 3" exhaust system is fine for the 3.5L models.

By all accounts........ a 3" exhaust *shouldn't* yeild any benefits over a 2.5" system in anything less than forced induction or high output N/A applications.

The forced induction bit is self explainitory - but, the definition of a high output N/A magna engine is abit obscure. Personally - I'd say with bigger cams and some head work, your car would probably be a contender for getting a gain out of a larger exhaust.

What warrants a 3 inch exhaust??

A little dog statue on the bonnet with the letters M A C K under him. :D lol

What warrants a 3 inch exhaust??

A little dog statue on the bonnet with the letters M A C K under him. :D lol


A civic with underbody neons and cut springs? :bowrofl:

TZABOY said:
yeah, not after more sound just chasing the power and trying to figure out what will work better. say the engine gets another 30kw and bumps up to 190kw at the wheels, then what?

190kw at the wheels on a N/A car i think that would warrant a 3in exhaust.

doesn't necessarily have to do with power; has to do with the rate of air flow which an engine produces; easy to see why trubo's like bigger zorsts! Only just finished 1st year and barely touched flow dynamics....

edit* an example; our uni's race car made a substantial gain through the use of a 8mm smaller throttle body and longer intake piping... some people could work it out for ya but i think its a multivariable equation thats out of my league; turbocharade and a couple of others might be able to help...

peace out

edit* an example; our uni's race car made a substantial gain through the use of a 8mm smaller throttle body and longer intake piping... some people could work it out for ya but i think its a multivariable equation thats out of my league; turbocharade and a couple of others might be able to help...

peace out
Is that the formula SAE car? Those things kick arse! I'm not 100% but i think the Adelaide uni one does 0-100 in about 6 seconds :shock:

howdy,
Hi.


just curious to when a 3 inch exhaust system is more efficent than a 2½ inch exhaust system. i know when u start making more power u get a bigger exhaust so when is it a good idea to go from a 2½ to a 3?
There's no real rules of thumb. It's really a science as to what you should go and it's so hard to get right without doing the math that people just go with their gut feeling. Usually it works out okay because of the varience with production engines etc.

Typically though more air in = more air out so if you're getting power from more air then a larger exhaust is probably handy. Something I'd point out is that my mates rally car has a 2 1/4 exhaust and it revs great. The thing is that the engine is a 1.3l I4 which makes me wonder what size a 3.5l V6 could take.

But you need to remember, bigger isn't always better, it's all about the right design for the desired application.

booya had 3inch zorst im pretty sure

i say stick with what u got ... money could be spent better else where i reckon;)

I've been wondering for a long time why virtually noboby has gone with a 3" exhaust - especially considering the stock exhaust is 2.4" mandrel bent, making the common 2.5" replacements seem very conservative to my thinking.

From my understanding, the main drawback to a 3" is more noise compared to a 2.5". I don't think there should be too much argument about a 3" potentially making more power though.

Typically the trade off for most N/A cars with large exhausts is a drop in power at lower revs, but an increase at higher revs. Not great for general cruising maybe - but when was the last time your car dropped into the bottom half of the rev range when at the drags or on a track?

I would like to think that our 3.5L's have enough capacity & torque to overcome any small drop in power at low revs (especially modded ones like Tzaboy's Ralliart). I guess it depends on your priorities and intentions for the car though.

Food for thought - the GTP Magna from several years ago was running a 3" exhaust. It had less engine mods than many cars in this club and it was only a 3.0L!

If your aim is to improve your track/drag times, i say go for it. Especially if you get your unichip/greddy/haltech etc chip re-tuned to suit the new exhaust and smoothen out the power curve.

Thanks for your help guys, if and when i make the next set of mods i want them to be as benificial as possible seeing it'll cost an arm and a leg (which wouldnt be a bad thing-weight reduction :bowrofl: )

If it helps I just got a 3inch TURBO back on my system and was deffiently worth it including highflow cat and stainless flexi

but i went from a 21/4 cat back :confused:

i got a 3in, hiflow cat back, made the engine rev a bit higher, made it more responsive, my engine is a 3.0 though

I've been wondering for a long time why virtually noboby has gone with a 3" exhaust - especially considering the stock exhaust is 2.4" mandrel bent, making the common 2.5" replacements seem very conservative to my thinking..................................


1 word.

insurance.

try and get full comprehensive with an affordable excess with a 3" exhaust on your car.... not gonna happen. maybe with just car or suncorp, but they will charge you a $3000 excess not to mention $2000 per year aswell. Keep the exhaust at 2.5" and you can get insurance with racq for $800/yr with a $750 excess

1 word.

insurance.

maybe with just car or suncorp, but they will charge you a $3000 excess not to mention $2000 per year aswell. Keep the exhaust at 2.5" and you can get insurance with racq for $800/yr with a $750 excess

You really have been misled dude........... I'm with just car, and for starters, they don't care what modifications have been done to the exhaust - it's just listed as a "upgraded exhaust", so a 4" exhaust would be treated the same as a standard exhaust with a 'straight thru' muffler fitted (extractors are listed as a seperate mod, but everything else in the exhaust system comes under "upgraded exhaust").

I also pay less than $800 / year and have a $750 excess. In my experience, they aren't any more expensive than regular insurers (infact I went from suncorp to just car and have saved money, even with my mods). Sure if you've got a turbo and $10,000 worth of stereo, and you're on your P's you'll be paying thru the nose........... but I'm sure you'd find they would be on par with other insurers (if other insurers would touch such clients).

And before you go and say it's cheaper for me because I'm older and have a perfect driving record.............. I only qualified for a Just Car policy just over 12 months ago (they won't touch anyone under 25), and my driving history is unfortunately less than perfect, all of which I have disclosed to them.

You really have been misled dude........... I'm with just car, and for starters, they don't care what modifications have been done to the exhaust - it's just listed as a "upgraded exhaust", so a 4" exhaust would be treated the same as a standard exhaust with a 'straight thru' muffler fitted (extractors are listed as a seperate mod, but everything else in the exhaust system comes under "upgraded exhaust").
Agreed. It's the same with my policy with NRMA.

My new NA 3.5L engine has recorded just over 244Kw's@wheels and im still using my old 2 1/2" Manderal bent exhaust with pacemaker extractors, hi flow cat, 2 resonators and magnaflow rear muffler. So i think unless your going forced induction 2 1/2" is fine. :)

My new NA 3.5L engine has just recorded 244Kw's@wheels and im still using my old 2 1/2" Manderal bent exhaust with pacemaker extractors, hi flow cat, 2 resonators and magnaflow rear muffler. So i think unless your going forced induction 2 1/2" is fine. :)

:shock:

...can I borrow it?

What warrants a 3 inch exhaust??

A little dog statue on the bonnet with the letters M A C K under him. :D


:bowrofl: :bowrofl: Best call ive heard in a long time.. :bowrofl:

When you go to 3inch your will need to make it quieter as with that massive cannon it will make the sound echo real bad.. :)

My new NA 3.5L engine has recorded just over 244Kw's@wheels and im still using my old 2 1/2" Manderal bent exhaust with pacemaker extractors, hi flow cat, 2 resonators and magnaflow rear muffler. So i think unless your going forced induction 2 1/2" is fine. :)
And how does that compare at the flywheel to a Holden 6.0l off the factory floor? Hahaha... what a joke :bowrofl:*





* @ Holden

howdy,

just curious to when a 3 inch exhaust system is more efficent than a 2½ inch exhaust system. i know when u start making more power u get a bigger exhaust so when is it a good idea to go from a 2½ to a 3?


when u put a snail under the bonet !

My new NA 3.5L engine has recorded just over 244Kw's@wheels and im still using my old 2 1/2" Manderal bent exhaust with pacemaker extractors, hi flow cat, 2 resonators and magnaflow rear muffler. So i think unless your going forced induction 2 1/2" is fine. :)

Where can I find out more about what you've done to get this much power out of your engine?? I know you've basically rebuilt from the ground up, with alot of bits you've had custom engineered - but some specific info would be great. Not asking you to give away all your secrets :cool: . (oh a dyno print out would be nice too)

On engine dyno it was around the 293kw@flywheel mark with old ecu mapping after remap it was just over 300kws@flywheel.

:shock: *speechless*......congratulations, hows it drive?

My new NA 3.5L engine has recorded just over 244Kw's@wheels and im still using my old 2 1/2" Manderal bent exhaust with pacemaker extractors, hi flow cat, 2 resonators and magnaflow rear muffler. So i think unless your going forced induction 2 1/2" is fine. :):rant::tantrum::rant:

which is to say.. nice one!

Commme on Jason, spill the beans! Sounds like a freakin beast!

I'm sure this thread has something to do with pre-friday's funny's?

I'm sure this thread has something to do with pre-friday's funny's?

No pre fridays funnies from me mate, if thats who your having a stir at.

People who speak to me on MSN know that ive been in the process of building up this engine for a few months now (when time permitted)

Anyway we shouldnt hijack TZABOY's thread anymore.
He asked a question, lets get it back on track...... now where did i put that 4" exhaust... :bowrofl:

*chuckles*

Anyway we shouldnt hijack TZABOY's thread anymore.
He asked a question, lets get it back on track...... now where did i put that 4" exhaust... :bowrofl:

Fair 'nuff.......... So start a thread about your project already.

For the benefit of us MSN haters :D .

1 word.

insurance.

try and get full comprehensive with an affordable excess with a 3" exhaust on your car.... not gonna happen.For what it's worth I have full comprehensive on my car with a 3" exhaust, cams, head work, ecu, modified plenum, stereo and a few other things for less than $900/yr and now that I'm over 25 my excess is stuff all.

well after reading all of this, without forced induction there is no need for a 3 inch exhaust so it looks like i'll just leave the one i have on there

A 5'' inlet with 2'' valves and a 4'' plenum :bowrofl:

Sorry to bring this thread back up, but what happened to Jasons VRX's posts about the new motor, is it being kept a secret or somthing?

Sorry to bring this thread back up, but what happened to Jasons VRX's posts about the new motor, is it being kept a secret or somthing?
No, it's not secret. It's just that whenever he posts something it's either deleted or others have a go at him about something. I'm surprised he's still on the forum. He must have thick skin after his treatment here and prior to being on here with other people he knows. I know I'd have given this place the finger and left long ago. He's one of the only members who's actually actively doing anything other than rims, stickers and a pod.

No, it's not secret. It's just that whenever he posts something it's either deleted or others have a go at him about something. I'm surprised he's still on the forum. He must have thick skin after his treatment here and prior to being on here with other people he knows. I know I'd have given this place the finger and left long ago. He's one of the only members who's actually actively doing anything other than rims, stickers and a pod.

I agree, I wasn't having a go at him. I'm glad he decided to stick around, his knowlage is very valuble. I was just wondering what happened to the post as I'm interested in his work :P

I agree, I wasn't having a go at him. I'm glad he decided to stick around, his knowlage is very valuble. I was just wondering what happened to the post as I'm interested in his work :P
Oh, don't worry, I didn't think you were. There's been a range of stuff done and he's not the only member who's gone down that path. We hope to see more results / info soon.

yeah have to say he would probably have the most knowledge about magnas on here ...... way more than anyone else by far

I wouldn't mind knowing a few of the tricks he has learn't along the way if he is willing to share, 244kw atw damn that is alot of power for a magna. I WANT ONE OF THESE MOTORS.
:bowrofl: :bowrofl: :bowrofl: :bowrofl: :bowrofl: