4" turboback?

[sho_tyme_psi]

I know I can get a DP in there without moving the alt.,and I got a NA housing for my car and going to have a remote oilfilter setup. Also on that note my turbo is a 3in. v-band exhaust so all i need is to step it up off it an inch. I did a search and couldn't find any threads on the 4in. on here, so if anyone knows of one, or pics would be great. but thanks again for all the support .

 

[bastarddsm]

or do like other people 4-5" straight out the side through the bumper. There was a mustang in hotrod a while back that wad a 6" out the side exhaust that car was making around 1000 hp, where as shep is making the same power on a 3.5" full length exhaust. The people that are saying it's overkill to have 4" are forgetting a key point, in turbo exhaust the freeest flowing is best. Why? Becuase we don't need to worry about scavanging. There is always positive pressure between the turbo and engine, therefore scavanging does not occour, instead we have BOOST. This is the same reason we don't run huge amounts of overlap. If this was a n/a application it would matter, becuase we want to keep the exhaust velocity up and the overlap high that way as the exhaust is leaving it helps pull in more intake charge resulting in better cylinder filling and more top end power. Contrary to popular belif backpressure is bad. Backpressure is needed in a two stroke with an expansion chamber to control where the power band is. The reason we don't see many 4" exhausts is because the gains are so minimal that they aren't worth the hassels of routing 4 inch pipe.

 

[UMR98GSX]

A local guy around here, Rob, runs a 4" on his spyder with a T66. Here is his website http://spyder.cruizer.net/ that might help you a little bit. There are no cats or resonators just a straight through muffler and it sounds like a sport bike and is loud as hell.

 

[green92gsx]

I know I can get a DP in there without moving the alt.,and I got a NA housing for my car and going to have a remote oilfilter setup. Also on that note my turbo is a 3in. v-band exhaust so all i need is to step it up off it an inch. I did a search and couldn't find any threads on the 4in. on here, so if anyone knows of one, or pics would be great. but thanks again for all the support .

I dunno man. When we fabbed up my 3'in o2/racepipe it was pretty damn tight. We had to make the turn down in sections to clear the alternator and oil filter with the n/t housing. I'm not saying a 4"in can't be done, I just haven't seen it accomplished yet.
I think Jon Ripple tried the 4'in o2 many moons ago. He gave up after many attempts from lack of space to work with.
Good luck!

 

[Coup D E'Tat]

I'll post up my 3.5" pics later tonight if I can remember

 

[CanadianTalon]

To the OP, stick with a 3" exhaust. Like everyone has said here, it is tried and true. If you were to come up to me and tell me you have a 4" exhaust I, honestly, would probably laugh at you because imo that is way to big, even for turbo.

Have any proof that 4" is "too big"? Nah, I didn't think so. Go look at the Honda guys, they're making 800 WHP on sub 2 litre motors and they're all picking up good power by moving to a 4" exhaust. Some friends of mine in Texas picked up ~30 WHP swapping from a full 3" exhaust to a full 4" exhaust on a car that was "only" making 600 WHP.

 

[dsmsucks]

This is crazy

People only want a 4in exhaust so they can say their running one. 1g gst guys can forget about it
The fastest awd dsm isnt running 4in exhaust.

 

[Coup D E'Tat]

This is crazy

People only want a 4in exhaust so they can say their running one. 1g gst guys can forget about it
The fastest awd dsm isnt running 4in exhaust.

Yea, sorry. We should all stick with 16G's since the "fast" guys are running those big turbos.

Please

 

[peregrine]

Yea, sorry. We should all stick with 16G's since the "fast" guys are running those big turbos.

good point.

 

[sho_tyme_psi]

UMR98GSX Thanks for the link I'm going to check it out when I get on my buddies computer I'm on dial up connected bout 20k CanadianTalon thats where I got the idea was from a Honda guy that ownes a speed shop in fairfield Ohio, it is a built ls/vtec with strait 4in. all the way back and it don't look out of place on the car and it sounds like a street bike but the nice part it it all makes it out back. Ide like to think everyone for the encouragement on it and if we stayed on the "It works for them it work for me" deal, we would still have a 11sec cars. The reason ppl go faster is stepping out on a limb and pushing the limits and trying something new.

 

[91-gsx]

I'm not trying to steal his thread. i have seen what he speaks of on the fact that the bigger the exhaust or lack of exhaust is better for turbo cars. if you look at a lot of Honda setups, like i just have currently seen as i was getting my electric cutout welded onto the first bend of my downpipe.... just want to say really loud, idles like a beast. anyway, Honda guys go to the guy i went to because he is basically a genius when it comes to welding, he makes his own turbo manifolds, piping and other things that require welding, his welds are really nice and strong. he had a setup for a Honda on one of his engines that had a cutout that opened right after the o2 sensor, my cutout is only 2.5" but who cares it is basically open o2 housing it shoots straight down, i might get some pics up. the Honda cutout was 3" this thing was huge, kinda looked bigger then 3". i noticed this is true on most carsthat are turbo, the shorter the exhaust the better, and the bigger the better, will tell you that you will notice a difference in how fast your car is once the turbo kicks in, but before that the torque seems to have gone down a little. it might seem that way to me because the exhaust is louder but it does not seem to go anywhere when i just cruise, i dunno, but my car does feel faster. and my setup cannot be to different then a 4" because i do not even have piping, OK maybe a foot. just my 2 cents, no if i can get the fumes from coming inside when i open it, ill be happy. ...later

 

[sho_tyme_psi]

Coup D E'Tat If you could post some pics that be excellent, 3.5 to 4in is not a big jump so it be close to the same. also you mentioned about muffler room I found some nice strait through stainless muffler from a diesel shop id put as a muffler at the end. I cant wait till the machine shop gets done with my motor so I can mock up a DP on it. but thanks again for all the great feedback and opinions.

 

[johnfsmith]

UMR98GSX Thanks for the link I'm going to check it out when I get on my buddies computer I'm on dial up connected bout 20k CanadianTalon thats where I got the idea was from a Honda guy that ownes a speed shop in fairfield Ohio, it is a built ls/vtec with strait 4in. all the way back and it don't look out of place on the car and it sounds like a street bike but the nice part it it all makes it out back. Ide like to think everyone for the encouragement on it and if we stayed on the "It works for them it work for me" deal, we would still have a 11sec cars. The reason ppl go faster is stepping out on a limb and pushing the limits and trying something new.

What speed shop? I live in fairfield

 

[sho_tyme_psi]

Rob at TPR has 4in. on his ek hatch, I do some business down there some and he fired it up the other day and it sounded great, also if you live down there where does everyone hang out at since the killed the whole cruise in thing? also is there much of a dsm scene down there. I'm hoping to get my car together to try to line up with that guy from basz with the ek GT42r car, heard he still does alot smack talking. none the less shoot me a PM and let me know.

 

[napkinthief]

what about weight issues, a 4" exhaust has to weigh considerably more than a 3"

 

[Coup D E'Tat]

More power > more weight.

Shit before you drive the car if you're that worried.

Sho time, I'll take some pics in a little bit.

 

[sho_tyme_psi]

Some pics would be great, napkinthief I would say I may pick up 8 to 10lbs total which not a big deal. I'm towing the car down to the shop today and hope to start with the exhaust from mid front seat to the back and ill have to wait to get the motor in to finish the rest. AndI have came to the conclusion I will keep it near stock hight.

 

[Boost Lee]

Local guy is running a 4" pipe on his Talon. If he is at the shop the next time I'm there, I'll grab some decent pictures.

You must be logged in to view this image or video.

 

[snox135]

Some pics would be great, napkinthief I would say I may pick up 8 to 10lbs total which not a big deal. I'm towing the car down to the shop today and hope to start with the exhaust from mid front seat to the back and ill have to wait to get the motor in to finish the rest. AndI have came to the conclusion I will keep it near stock hight.

In case you are wondering 4" stainless steel 16ga. tubing weights .69lbs. per foot more that 3" stainless steel 16ga. tubing. Also if you are concerned with clearance issue you could use 4" oval tubing but that would cost considerably more.

 

[larsrya8]

If you keep the car at about the stock height you should be fine. That way you'll be safe from bottoming out on the exhaust pipe. If you can make it fit on the chassis you should be all set to go.

I agree with the first few posts in the thread. While 4 inch isn't needed, if it is easier for you then go ahead and do it. I wouldn't run it, even if it was easier, mostly because I'd be concerned with the noise. Those who upgrade from 2.5 to 3 inches notice a drone at certain RPMs... let us know if this gets worse or not with a 4 inch. I also wouldn't run it because I'd be worried about bottoming out and denting the pipe. There are already enough driveways in my area that I have to hit at funny angles, I don't need any more to worry about.

The argument that a school bus uses a 4 inch exhaust was rather funny, but made a weak point. A school bus is a diesel with a large turbo, and it's really long. The school buses in my area have the exhaust pipe running the full length of the bus. The exhaust coming out of that pipe has to be really close to the ambient temperature after running that length. For that reason the buses have 4 inch pipes. That and there's a lot of room under that thing for a huge pipe.

Weight will not really be an issues. Depending on a driver's size, it's about the difference between them eating a meal right before racing or starving themself. Well, maybe a little more, but it doesn't matter.

Coup D E'Tat - I don't get your 16G joke. Wait, now I do. Touché.

So in summary, if you want to run the 4 inch exhaust, go right ahead. I just listed the most valid reasons I could find that might make it difficult. If you can iron out those issues it'll work for you. You're car will probably sound like a sport bike, we'll see. Good luck with the exhaust and the GT40.


P.S. Boost Lee - that is a hot pic... if it was bigger it'd be my desktop wallpaper.

 

[gastroker]

I'm running 4" turbo back on my 2g AWD. I have a 4" v-band right off the turbo.
I had to relocate the alternator to the back side (which required notching the 2g frame)
And I relocated the oil filter and I use an external oil cooler. All these things were not done just for the 4". They were done for various reasons which lead up to me realizing that "hey, I now have enough room for 4" exhaust" It is a Very tight fit still but the bend coming off the turbo and routing its way to the tunnel is pure art work. I only have one pic in my gallery and its a shot from the back of the car with a shitty phone camera....give me about a week to put the motor back in and I'll take some good ones from the engine bay.

 

[speedy13]

or do like other people 4-5" straight out the side through the bumper. There was a mustang in hotrod a while back that wad a 6" out the side exhaust that car was making around 1000 hp, where as shep is making the same power on a 3.5" full length exhaust. The people that are saying it's overkill to have 4" are forgetting a key point, in turbo exhaust the freeest flowing is best. Why? Becuase we don't need to worry about scavanging. There is always positive pressure between the turbo and engine, therefore scavanging does not occour, instead we have BOOST. This is the same reason we don't run huge amounts of overlap. If this was a n/a application it would matter, becuase we want to keep the exhaust velocity up and the overlap high that way as the exhaust is leaving it helps pull in more intake charge resulting in better cylinder filling and more top end power. Contrary to popular belif backpressure is bad. Backpressure is needed in a two stroke with an expansion chamber to control where the power band is. The reason we don't see many 4" exhausts is because the gains are so minimal that they aren't worth the hassels of routing 4 inch pipe.

I agree.your 100% right.I don't agree on how you initially aproached the people on this thread it was kinda wrong,but cmon guys lets talk cars here,dont take everyones coments so personal,when you guys start to argue you sound like bitches on the rag.

P.S. to the people running 4" exhaust,you guys are absolutly nuts!!!

 

[sweet97]

Local guy is running a 4" pipe on his Talon. If he is at the shop the next time I'm there, I'll grab some decent pictures.

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Wild engine pic! Could youdo another wit white arrows(any color will do) pointing out major components? Looks like you used a sidemount as a radiator. Not sure the purpose for the long pipes except to try to increase lo end torque? What turbo and where is it? It appears the downpipe angles back from the turbine. I originallt said 4" was overkill nut I must admit I like different and wish the Thread starter success as I have seen 4" done before. Heck I have 2 CYCLONE intakes here as I found tem to b interesting but KEDYDIVER said I was moving too much air for tose intaes but his EVO16G spools almost immedialty with one so different can be good. I was thinking of stripping the butterflies from one and trying that, all runners always open, half long and half short.
Vinstalon on the Buschur site has his exhaust exiting in front of his drivers side front wheel! Imagine the noise here! He at least has a muffler! mark

 

[sho_tyme_psi]

Thanks for all the replies still coming, Gastroker if you can get some decent pics of the setup you got with moving the alt. that would be excellent. Boost Lee that pic is great is it your car? I was going to originally run a setup close to that but wanted to keep close to stock location and sandwich in the A/C in it still, also wondering how much that lowered your temps at the turbo its self. I hate to let some of you down but do to recently no work I am going to resort to aluminized pipe from the flexpipe back leaving the DP and flex pipe SS but plan to Finnish out in SS this spring. Thanks for all the replies.

 

[gastroker]

I sure will...I have a video of my car too but its on VHS...I need someone to covert it to digital.... I think I have some old pics of the frame where I notched it I'll try to get those pics up in the next couple of days...