RWHP question?
04-25-12, 08:01 PM
#1
Mike
Thread Starter
RWHP question?
So I am almost done with my 'build' (for now lol) and I just put in my Rtek 1.8. I was wondering if someone can give me a estimate RWHP with my set up. I am running a S4 13B (TII) extended street port (P/S, OMP, A/C & emissions delete, etc), stock S4 turbo (15 PSI), 720cc injectors (primary and secondary), walbro 255 with adjustable FPR, front mount IC, and full racing beat exhaust. If someone can guess what kind of HP im looking at I would greatly appreciate it! Feel free to give some suggestions and constructive criticism on the car.
04-25-12, 08:18 PM
#3
Mike
Thread Starter
I know the turbo wont last long if I keep beating it but I was planning doing a huge turbo set up soon anyway. Do you really think I would run into a problem with my air being too hot with the front mount? I heard of these problems with the stock mount but I though Id be in the clear if I changed the intercooler set up.
04-25-12, 08:23 PM
#4
Don't push a stock turbo past about 12 psi. You get so far outside the efficiency range of the turbo that all you're doing is superheating the air. There's no more power to be gained, but you'll increase IATs and risk of detonation. A stock turbo won't even hold that kind of boost for more than ~1000 RPM anyway.
04-25-12, 08:35 PM
#5
Mike
Thread Starter
Don't push a stock turbo past about 12 psi. You get so far outside the efficiency range of the turbo that all you're doing is superheating the air. There's no more power to be gained, but you'll increase IATs and risk of detonation. A stock turbo won't even hold that kind of boost for more than ~1000 RPM anyway.
04-25-12, 09:09 PM
#6
No modding is really needed to make it boost high, just the free flowing exhaust and intake. If they guy says he "modded it" perhaps he disabled the wastegate completely and now you're cooking it. Unless you start correctly modifying/fixing things, the only boost control you have is your foot. For now you should pull it off and port the wastegate.
04-25-12, 10:39 PM
#7
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ok ill take you guys advice! but I need help with lowering the boost...Its not being controlled by a boost controller. The previous owner did some kind of mod to the wastegate or something and made it reach these boost levels. Would you guys be able to tell me what could have been to do the turbo so it can be reversed (thats if reversing it is possible)..? thanks for the quick replies!
If the previous owner actually ran the turbo at 15psi then you may want to just send it to BNR for a full rebuild and have them fix the wastegate.
http://gonzaloherrero.com/bnr/index....d=67&Itemid=89
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04-26-12, 12:34 AM
#8
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All this fuss about not running a stock turbo that high..
I ran stock turbo at 14-15psi for 3+ years, later upgraded to a BNR stage4
i still got it on the shelf, there is absolutely nothing wrong with that turbo..
My first BNR turbo has been fried already..
I ran stock turbo at 14-15psi for 3+ years, later upgraded to a BNR stage4
i still got it on the shelf, there is absolutely nothing wrong with that turbo..
My first BNR turbo has been fried already..
04-26-12, 12:52 AM
#9
I ran mines at 14 psi for a year now after rebuilding it.
The thing is, its 14 psi through 2500-5000rpm, after 5krpm it drops to 8psi all the way to 8krpm because the turbo is just too small.
I can see it going badly if it was holding 14psi all the way to redline. But its only 14psi through the midrange. At 14 psi is is pushing the effeciency of the turbo, even at midrange rpm. Rotary engine sucks in a lot of air for such a small turbo.
The thing is, its 14 psi through 2500-5000rpm, after 5krpm it drops to 8psi all the way to 8krpm because the turbo is just too small.
I can see it going badly if it was holding 14psi all the way to redline. But its only 14psi through the midrange. At 14 psi is is pushing the effeciency of the turbo, even at midrange rpm. Rotary engine sucks in a lot of air for such a small turbo.
04-26-12, 01:17 AM
#10
I ran a stock s5 turbo @ 7-9psi (ported wastegate pressure) for 2 years w/o issure, I then upgraded to a v-mount IC but didn't have time to weld on the BOV flange. Within a couple weeks the CHRA started leaking oil. I then swapped out that turbo for another stock S5 unit and ran that @ 15+ psi (ebc) for over a year.
So in my experience compressor surge is far more dangerous than running the stock turbo outside its efficiency range in terms of damage to the turbo itself. HOWEVER intake temps past 12psi are stupid high, and I'm sure contributed to the death of my motor (along w/ agressive stock timing maps and "fuel economy" tune)
So in my experience compressor surge is far more dangerous than running the stock turbo outside its efficiency range in terms of damage to the turbo itself. HOWEVER intake temps past 12psi are stupid high, and I'm sure contributed to the death of my motor (along w/ agressive stock timing maps and "fuel economy" tune)
04-26-12, 06:38 AM
#11
Mike
Thread Starter
It doesnt seem like he disabled the waste gate though...the boost seems controlled and solid and the wastegate is still intact. Its still has spring pressure and the vac hoses connected to it. Now im confused! lol! Do you think ill drop some peak boost with the front mount installed? I get it in the mail today. Right now im running the stock mount...
04-26-12, 09:16 AM
#13
Mike
Thread Starter
Yeah that's were I'm at now...I kind of don't like the idea of that little turd of a turbo pushing that much boost but like i said I didn't think I would run into to much of a problem with a front mount. But I would really appreciate it if someone can help me with my boost problem though. I'd like to be able to control my boost. Lol
04-26-12, 05:59 PM
#17
Mike
Thread Starter
Does anyone one know what could have been done to the turbo to make it boost this way? Id really like to fix this so I can save for my original build (GT45 on E85). Help is much appreciated!
Last edited by 3xBlack Vert-top Mike; 04-26-12 at 06:01 PM. Reason: forgot to put ask...
04-27-12, 11:27 AM
#18
+1, i creeped to 12+ with a 34mm ported wastegate... restrictor plate with 1inch whole. back to 5 psi, and now i have manually raised to boost back to a safe and steady 10 psi, now it hits 10 instantly and stays there until past tq peak. much faster, and much safer.
04-27-12, 02:18 PM
#19
If the actuator is connected properly, you're just boost creeping due to the micro 13mm S4 wastegate.
04-27-12, 05:26 PM
#20
Mike
Thread Starter
Check that the wastegate actuator has a pressure source hooked up to it. If it's disconnected, the gate will not open and boost will go unchecked until the turbo's size/efficiency limitations force it to drop off.
If the actuator is connected properly, you're just boost creeping due to the micro 13mm S4 wastegate.
If the actuator is connected properly, you're just boost creeping due to the micro 13mm S4 wastegate.
04-27-12, 07:46 PM
#21
On a stock S4 turbo you are maybe at 350RWHP? Man... I'd love to drive on THAT planet 
Supposedly some have pushed 280. And that is a stretch, possibly with auxiliary injection and they weren't saying anything.
Long story short, you are not anywhere close to your friends 338RWHP. Then again he could be in la-la land as well.
Supposedly some have pushed 280. And that is a stretch, possibly with auxiliary injection and they weren't saying anything.
Long story short, you are not anywhere close to your friends 338RWHP. Then again he could be in la-la land as well.
04-28-12, 09:16 AM
#22
Mike
Thread Starter
+1, i creeped to 12+ with a 34mm ported wastegate... restrictor plate with 1inch whole. back to 5 psi, and now i have manually raised to boost back to a safe and steady 10 psi, now it hits 10 instantly and stays there until past tq peak. much faster, and much safer.
On a stock S4 turbo you are maybe at 350RWHP? Man... I'd love to drive on THAT planet
Supposedly some have pushed 280. And that is a stretch, possibly with auxiliary injection and they weren't saying anything.
Long story short, you are not anywhere close to your friends 338RWHP. Then again he could be in la-la land as well.
Supposedly some have pushed 280. And that is a stretch, possibly with auxiliary injection and they weren't saying anything.
Long story short, you are not anywhere close to your friends 338RWHP. Then again he could be in la-la land as well.
04-28-12, 11:39 AM
#24
if you pulled on him with a stock turbo, something is wrong with your friend setup there.
If you had 720 injectors all around, no way you are making over 300hp, especially on a rtek 1.8 since you cant adjust timing and fuel.
With the information you posted its making atleast 220-240rwhp depending on the health of the engine.
If you had some 1/4 mile times, it makes it a little bit easier to calculate horsepower. it wont be accurate but it would give a ballpark figure. Or you can go to a dyno.
If you had 720 injectors all around, no way you are making over 300hp, especially on a rtek 1.8 since you cant adjust timing and fuel.
With the information you posted its making atleast 220-240rwhp depending on the health of the engine.
If you had some 1/4 mile times, it makes it a little bit easier to calculate horsepower. it wont be accurate but it would give a ballpark figure. Or you can go to a dyno.
