Hi guys im thinking about going with a single hks hi power TI exhaust. I have a full 3 inch dual. I have some questions I would like to ask the guys here. Ive been running the hks custom dual set up for a while but I want something a bit deeper and louder for cruising. Here are my Q's

1) I have heard that a 3 inch dual set up is way to much flow for a stock block VQ is this true?

2)Will I get any gains in hp or torque? In the high rpm's my torque curve drops badly will this help since ill be adding backpressure.

3) My car is tuned for the dual 3 exhaust will I have to retune again when putting a single 3 inch? I have Wg dumps so I don’t really have allot of exhaust flow going through my mufflers allot of it goes by the dumps.

4)My plans are basically to run a 3inch pipe of each AAM 3inch turbo back pipe and the mating them in a y-pipe figure continuing with a 3inch to the exhaust is this the right way. My worries are that their will be allot of backpressure once the gasses get to the single 3 inch pipe or am I wrong here.

Suggestions are welcome thanks in advance.

 

I know squat about turbo'ed cars , but from what Ive read on this forum . You will lose quite a bit of power going back to a smaller exhaust . You want the most free flowing exhaust with a turbo .

 

GReddy EvoTT FTW.

 

yea I have read things like that also but I have also read that you need some backpressure because if you have to much flow then you loose allot of torque which its happening to me. That’s why im trying to get some info here and especially from the shop guys lets see what they say on this.

I have read that on a stock block VQ 3inch dual is to much and on top of that I have 3inch turbo back pipes and also w/g dumps so I don’t think it gets any more free flowing then what I have. I was thinking maybe if I restrict it a bit I might gain some back up top. here is my dyno chart. As you can see my power is solid and I don’t drop power at all but if you look at my torque its not that good in the first one its drops real bad and in the second one iT kinda levels out pretty much the entire way but drops a bit at the end. All I want in to kinda kept the torque going up instead on dropping or leveling out maybe a little back pressure would help. That’s why im trying to get the opinion on the shops guys and people that a know their S*** real well. BTW This is a dyno dynamite never heard of it but they told me it reads around 18 to 20 percent lower then a dynojet I think it reads I bit higher maybe around 14 to 16 or around that area. ANYWAYS PLEASE I NEED SOME INPOUT HERE IT WOULD BE GREAT THANKS.

 

yeah dual 3 inch for just 400whp is not going to benefit you. The dynocharts prove that if it's truely a before/after dyno. That's a 40tq loss for most of the powerband except maybe above 6500 rpms

here's an overlay...

 

No No its the same day but two passes in the dyno i dont know why they came out so different maybe the first one was done at 4th and the second one done at 3rd thats why maybe my torque curve was so much better in the second chart then in the 3rd cause in lower gears you have more torque.

 

anyone

 

I have a Greddy TT kit with AAM 3" open dumps and 3" APS exhaust and my TQ doesn't really drop until 6000 rpms. My TQ peaks at 347 ft/lb @ 3600 rpm and at 6000 rpm is 340 ft/lb.

Of course my car was tuned by Sharif from Forged Performance. I would shoot him a email or PM.

I don't have a .jpg of the Dyno Dynamics graph, but you can view my dyno sheet at the end of this video that Sharif made.

http://www.youtube.com/watch?v=67BCKVwtXaw

 

it also depends what engine management you use helps out a bit. But what im trying to find out is if the single exhaust will hurt or improve.

 

Carv2 is using the JIC single 3". They are making nice power. Pushing well over 6xx. You are talking about a single exit correct?

 

When it comes to turbos, the more flow you have, the more power you can make. A dual 3" will be much better than a single 3".

 

+1. I know ppl switch from single to dual not the opposite. keep what you have!

 

3" single over a TD 3" will hurt performance. You thinking that adding backpressure will increase top end TQ or decrease TQ drop off up top is silly. That is likely timing related as who ever tuned your car went conservartive up top, hence the TQ drop off with pump gas. If you did a race gas map with advanced timing I guarantee your top end TQ would be much better. Id stick with the 3" TD...

 

I was also thinking about the timing but wasn’t sure. Also that’s what I was trying to find out if it would hurt me badly switching exhaust to a single I know it going to sound better (at least in my taste) since it has two flows converting into one at idle my car is low due to the fact that its not built and also the idle is like 650 to 680. I might not end up building it since their is to many things to worry on the VQDE when building it for high power so I might just keep it as a daily driver and buy something else when im done with school. But thanks allot guys and if anyone has any more input post ill gladly accept everyone’s opinion.

BTW how the hell do the supras get to have a 4 to 5 inch pipe with the hks hi power exhaust with the 3inch inlet. I’m guessing they cut the 3 inch inlet barrel all the way to the canister and the open the 3inch whole in the canister bigger correct or im way off.