Is it possible to make around 300-315 whp with a 2.5" exhaust and gt2871r?

[imnotniko]

hey i want to get rid of my 3 " exhaust and put on a 2.5" because its pretty loud.. i'm making with my current setup 334 whp on 19 lbs on a 2871r..

i'm building the motor... (mild buid... cams valves springs retainers pistons rods)

so i'm pretty much curious if i will still make around 300-315whp on 19lbs with a build motor and 3" dp to 2.5" catback exhaust. thanks!

[S14toRPS13]

With some bigger cams I don't see why you won't be able to make close to the same numbers you were putting out with a 3" exhaust. I wish I had some dyno sheets to prove it, but it's just my opinion. What exhaust are you using that is too loud. I'm using an Apexi N1 over 3" and my car's quieter than most other street cars at the track. Only reason why I'd like to get rid of my exhaust is because I don't want to attract the wrong attention on the road. If you do go the 2.5" route. Post up your results though. I'd love to see what difference there might be.

[imnotniko]

i think im gonna try using a 2.5" exhaust and see what happens.

[kentuckyslider]

i think im gonna try using a 2.5" exhaust and see what happens.

I'm sorry but IMO you are crazy if you replace your 3" with 2.5". You will be spending 5 times the money and decreasing power to make it quieter when you could just have a 3" bullet muffler welded in at an exhaust shop. Pleas don't do that. It makes no since at all.

Try this instead. It will make it sound nice and you won't lose so much spool up. What will kill you is tha slower spool!!

http://www.summitracing.com/parts/MPE-14419/

[shift_SRDETuser]

I use a

I'm sorry but IMO you are crazy if you replace your 3" with 2.5". You will be spending 5 times the money and decreasing power to make it quieter when you could just have a 3" bullet muffler welded in at an exhaust shop. Pleas don't do that. It makes no since at all.

Try this instead. It will make it sound nice and you won't lose so much spool up. What will kill you is tha slower spool!!

http://www.summitracing.com/parts/MPE-14419/

I use a high flow cat and a big magnaflow muffler while it is still loud it is nothing like some peps cars and it has a nice powerful rumble at idle. I make mid 300s for power so this should give you an idea that it is possible.

[imnotniko]

i just drove my car today for the first time in about 3 weeks.. and i think im gonna keep the 3 inch and just put a high flow cat on the car and one of those magnaflow mufflers...

also.. all you guys that are running 2871r turbos... do you daily your car? and if so are you always driving around on 19lbs of boost.. or do you have an electronic boost controller and last do you have a stock manifold and wastegate?

[shift_SRDETuser]

i just drove my car today for the first time in about 3 weeks.. and i think im gonna keep the 3 inch and just put a high flow cat on the car and one of those magnaflow mufflers...

also.. all you guys that are running 2871r turbos... do you daily your car? and if so are you always driving around on 19lbs of boost.. or do you have an electronic boost controller and last do you have a stock manifold and wastegate?

I drive it a lot but I love driving my truck as well so I do not daily drive it. Low setting is around 8 to 10 lbs of boost of the waste gate and 18 lbs is what I run on high boost with my profec B. I run a tomei tubular header which I will be selling and going to a CODYACE special extrud honed OEM manifold. So manifold will be modified stock and wastegate is aftermarket. Most of the time I handle most cars with 10 lbs of boost however when I want to kick the crap out of a mustang, 350/370z or maybe even a regular vette. I run the 18lbs.... but not all the time.....

[imnotniko]

ok so if i get an electronic boost controller and keep my waistegate now.. i can lower the boost to 10lbs.. right?

but would i have to re tune? and when i got it tuned.. i wanted it to be on 10lbs.. but they said i had to put it up to 19lbs because it was creeping or something.

edit: doing a mild build with pistons rods cams valves springs and all that.. so throw that into the question with would i have to re tune?

[shift_SRDETuser]

ok so if i get an electronic boost controller and keep my waistegate now.. i can lower the boost to 10lbs.. right?

but would i have to re tune? and when i got it tuned.. i wanted it to be on 10lbs.. but they said i had to put it up to 19lbs because it was creeping or something.

edit: doing a mild build with pistons rods cams valves springs and all that.. so throw that into the question with would i have to re tune?

why would you not. I have made little changes in the exhaust and had to have it fine tuned on the dyno. I am sure I will have to have it rechecked when I change out to the new manifold. Better safe than sorry

[S14toRPS13]

I drive my car 3 to 4 times a week at 14 psi. I want to get it tuned properly at 17 or 18 psi and daily it like that. It's not going to see the the 18 psi unless I push it. BTW, I'm running GT2871R .64 and using a Greddy Profec B boost controller, with a stock manifold.Why would you want an electronic boost controller if you're going to keep it 10 psi? I'm a bit confused here. Just use an adjustable wastegate actuator. It should be able to hold 10 psi perfectly.

[shift_SRDETuser]

the wastegate is to 10 psi or so and the profec holds 18 psi perfectly. I would a lot rather push one button to HIGH than have to screw around with a wastegate -- plus only push it when you have to -- that way the engine lasts longer -- but I run a Power FC too so I know when detonation occurs -- keeps it even safer

[imnotniko]

the wastegate is to 10 psi or so and the profec holds 18 psi perfectly. I would a lot rather push one button to HIGH than have to screw around with a wastegate -- plus only push it when you have to -- that way the engine lasts longer -- but I run a Power FC too so I know when detonation occurs -- keeps it even safer

i guess i should post up my setup so you know what im working with to when i ask all these questions..

ecu:Apexi power fc L-jetro335whp 302torque

engine:garrett 2871r turbo @ 19psiarc oil panapexi 1.1mm headgasketgreddy oil coolerhks grounding kitapexi short ram intakez32 mafwarblo 255lph fuel pumpgreddy intercoolertomei rocker arm stoppersbm fuel pressure reg. and fuel linessards 555cc injectorsarp head studsgreddy tr turbo back exhaust w/ cat deletecusco oil catch canflex lite fans

Drivetrain:nismo 2way diff.exedy single plate clutchnismo slave cylindernismo clutch linesb&m short shifter

in all.. my goal is to do a mild build on the head and block and re build my turbo and set it around 10lb's when im dailying the car.. and getting an electronic boost controller to up the boost every now and then.. i also want to get rid of my diff and get a regular lsd (i don't like the clicking when i go around corners with this diff)

[shift_SRDETuser]

I have not had any trouble with my VLSD -- knock on wood --- Yeah I run around 10 lbs most of the time and I guess that is around 250 to 260 horsepower which is still plenty on the streets. You might should get some 740 injectors since the 555s could get tapped out quickly. Your setup looks fine though and it should be really reliable if done correctly. Without a LSD the high boost power IMO is not safe so you have to be careful.

[S14toRPS13]

Okay I see what you're saying. Daily it at 10 psi and turn on your ebc for 18 psi.

I'm just saying you could just leave it on 18 psi? If you're not driving hard, it won't see 18 psi on a daily basis is what I'm saying. It'll only see it when ever you hammer the throttle down. But I can see where you're coming from. You don't need 18 psi when you're just passing up other cars on the freeway when 10 will do. When I had my HKS GT2530, the ecu was tuned for 18 psi, but I drove it around at 10 psi for a while because I needed a new boost controller. Driving was just a normal at 10 psi as it was at 18 psi. It didn't run any richer, foul my plugs up or turned my bumper black.

I also have a S15 hlsd on my car and I'd recommend that if you want a good lsd for daily driving. Runs just like an open diff under normal driving and spins both tires when you hit the throttle hard. I still have no traction but atleast now the rear end is fighting for traction where as before one wheel would just spin to hell. Okay enough rambling about random stuff for me.

[OM3GA]

I was thinking of going with the Buddy club Spec II however i am afraid that IT might be too loud. Im just getting tired of the giant can look and i dont like the stock look either.

[LayNLow240]

I was thinking of going with the Buddy club Spec II however i am afraid that IT might be too loud. Im just getting tired of the giant can look and i dont like the stock look either.

The spec 2 is nice, my buddy has one and I love it. But I have a resonated Reinhard and I love it too, its a little quiter than the spec 2.

[S14toRPS13]

I was thinking of going with the Buddy club Spec II however i am afraid that IT might be too loud. Im just getting tired of the giant can look and i dont like the stock look either.

I feel the same way. I want something that can still flow like my N1 but less discreet and not louder than my N1.

[kentuckyslider]

I ran 19-21psi on my 2871r for 2 years but I only put about 3000 miles a year on the car since it wasn't my DD. I would do a 14psi WGA and run up around 21-22psi at the track or if racing. The only advantage to the EBC is being able to adjust boost in car. I would buy a $70 turboxs mbc and have it set for 21-22psi and keep it in the glove box. 14psi on WG and 21-22psi with MBC inline.

[PyR0NiAk]

Will an MBC even hold 21-22 psi? I've always heard they have spiking issues...

[shift_SRDETuser]

I run 8 lbs on the wastegate and 18 lbs on high boost with a profec B

works great even in low boost ......

[imnotniko]

thanks for all the replies and help guys.. i actually just got myself a car cover.. and i'm putting my car away for the rest of the winter.. i'm gonna start buying parts and doing work on it in late feb early march.

on the good news side.. my friend is selling me his 02 chevy malibu for 1800.. its got 52,000 miles on it and runs great.. just has a big dent in the front fender..

bad news hes leaving for the army in 3 days.