Hypergear Turbochargers and High flow Services Development thread

[Lithium]

Can someone explain to me what causes too much exhaust back pressure?

Finally got the car tuned today on a build motor

Made 284 rwkw

Specs are a built forged, ported motor. SS2 turbo internal gate. 98 octane. Brae manifold, 3 inch JJR, not car, 3 inch hks cat back exhaust.

Trent said the turbo maybe a restriction. It had too much back pressure, causing the turbo to run hotter, and he couldnt run as much timing as he wanted too.

Stao said I have a 0.82 rear housing so it shouldn't be an issue

Car seamed to stop making power after 5-6k rpm

Does anyone have any ideas?

In saying that he said if I didnt have the restriction and it held boost I would be making ~ 330rwkw

It's not just a/r which can cause it - too small a turbine housing, other blockages down stream of the turbo (collapsed cat/generally too restrictive exhaust) etc can cause that. Is it an "FNT" turbo?

[Manuel Kasko]

Possibly going to this year aim towards getting my SS1PU on E85.

Stao how much did you say that you think it could make on E85?

Also will my HKS 555 injectors be suited for E85?

I know they probably will limit the power I can push but does anyone have an idea of how much power they could flow

[GTScotT]

Has he dropped the exhaust before the cat(decat)? Also, is your dump a 1 or 2 piece item?

[ARTZ]

ItS a bellmouth...Damn that's a

Bit of a bummer Tony . All I can think is maybe with all the head porting and such is you have increased flow so much that it bottlenecking at your IG and exhaust..did you do cams as well?

You have to remember the ss2 has been designed solely around a standard rb25..the only reason stao runs forgies is so his pistons don't fry when he drops 30pis of boost into them for testing...porting the head changes all.its flow charecteristics

I'd be tempted to stock a fat external gate and screamer on it , should yield a good result, bit of messing about tho...but just get a different turbine housing and weld a gate to it could work wonders..

[Lithium]

555cc injectors on E85 will be very power limiting... like <300kw

[GTScotT]

Agree that gating the c*nt will work but think you should look for the restriction first. Rule out all possible faux pas before proceeding to make changes.

I feel it will be a collapsed muffler or similar. When a spot weld breaks down in a muffler the glasspack starts to hang down a touch and causes all world of issues. I've seen cars lose heaps of power like that and have bad detonation issues.

[hypergear]

That is Pump 98 result. He's coming around after the track day, I think its in his return flow cooler.

[ARTZ]

its a blitz isnt it?

[ARTZ]

Possibly going to this year aim towards getting my SS1PU on E85.

Stao how much did you say that you think it could make on E85?

Also will my HKS 555 injectors be suited for E85?

I know they probably will limit the power I can push but does anyone have an idea of how much power they could flow

just push em and see...should go close...

[34GeeTeeTee]

Agree that gating the c*nt will work but think you should look for the restriction first. Rule out all possible faux pas before proceeding to make changes.

I feel it will be a collapsed muffler or similar. When a spot weld breaks down in a muffler the glasspack starts to hang down a touch and causes all world of issues. I've seen cars lose heaps of power like that and have bad detonation issues.

[blah_blah]

exhaust restrictions: Blocked/Collapsed Cat Converter, Blocked/Collapsed Muffler, Exhaust or section size to small

Theres not a whole lot to worry about on a turbo car, If he thinks its an exhaust restriction start at the Cat and work back

Its a 3inch straight through exhaust with a mid muffler between the cat and cannon

It's not just a/r which can cause it - too small a turbine housing, other blockages down stream of the turbo (collapsed cat/generally too restrictive exhaust) etc can cause that. Is it an "FNT" turbo?

Pretty sure it is. Stao can clarrify. I bought it late last year

Has he dropped the exhaust before the cat(decat)? Also, is your dump a 1 or 2 piece item?

Nah Trent didn't drop the exhaust for a run.

The dump pipe is a 1 piece 3inch pipe

ItS a bellmouth...Damn that's a

Bit of a bummer Tony . All I can think is maybe with all the head porting and such is you have increased flow so much that it bottlenecking at your IG and exhaust..did you do cams as well?

You have to remember the ss2 has been designed solely around a standard rb25..the only reason stao runs forgies is so his pistons don't fry when he drops 30pis of boost into them for testing...porting the head changes all.its flow charecteristics

I'd be tempted to stock a fat external gate and screamer on it , should yield a good result, bit of messing about tho...but just get a different turbine housing and weld a gate to it could work wonders..

That's what someone else has said as well:

Seeing the way the car hits boost and how quickly it hits max boost leads me to believe its not an exhaust restriction (it is running a 3" turbo back exhaust)

Being a 3" right through would make me "expect" a higher power figure before the exhaust system came into question...

I have seen the same turbos make higher power figures on stock motors, but this motor has a very highly modified cylinder head, which in my opinion is causing the turbo to over speed too quickly...

What works on a standard configuration will not necessarily work on this one...

As for the boost drop, COULD the standard bov be bleeding out once it spikes to max boost?

Agree that gating the c*nt will work but think you should look for the restriction first. Rule out all possible faux pas before proceeding to make changes.

I feel it will be a collapsed muffler or similar. When a spot weld breaks down in a muffler the glasspack starts to hang down a touch and causes all world of issues. I've seen cars lose heaps of power like that and have bad detonation issues.

Wouldn't a collapsed muffler or exhaust restriction tarnish the turbo coming on to boost? As it seems to hit 24psi pretty quick?

[GTScotT]

OK, ok. I should have said 'will help overall' lol. My bad, was rushing to type on the train.

Blah_blah a collapsed muffler probably wouldn't hurt spool that bad if it wasn't fully collapsed. If it was only partially damaged it would more so create turbulence which will hurt outright flow (power up top).

Get him to do a power run with it dropped at the end of the dump. I am confident it will jump in power.

[Sunkist]

f**k the exhaust off and get Scotty to weld an external gate and 3.5 inch exhaust. If it doesn't work it'll be fun lol

[donmik]

Tonys engine was built with high rpm in mind...

Hence why it is making boost later then most engines with the same set up..

Porting a cylinder head dramatically changes flow characteristics... and whilst I won't disclose what was done, it was major port rework...

I don't doubt the power will jump with an open exhaust, but I still feel it wont unleash the full potential!

Ps. And I do understand there are other aspects that need rectifying for example; heat control, intercooler plumbing... just to name a few

[petero'nell]

It needs external gate.

[scotty nm35]

Tonys engine was built with high rpm in mind...

Hence why it is making boost later then most engines with the same set up..

So it made the engine worse in this instance, bigger isn't always better, especially with head porting. (I am of the belief they are too big already) 1 inch manifold runners are plenty too.

Who wants to rev an RB anyway, it will end in tears every time. Moar boost not revs.

[blah_blah]

OK, ok. I should have said 'will help overall' lol. My bad, was rushing to type on the train.

Blah_blah a collapsed muffler probably wouldn't hurt spool that bad if it wasn't fully collapsed. If it was only partially damaged it would more so create turbulence which will hurt outright flow (power up top).

Get him to do a power run with it dropped at the end of the dump. I am confident it will jump in power.

f**k the exhaust off and get Scotty to weld an external gate and 3.5 inch exhaust. If it doesn't work it'll be fun lol

Waiting on a reply from Trent to see if this could be the issue

If so, Ill try find a dyno to run on this saturday with the cat back exhaust dropped

So it made the engine worse in this instance, bigger isn't always better, especially with head porting. (I am of the belief they are too big already) 1 inch manifold runners are plenty too.

Who wants to rev an RB anyway, it will end in tears every time. Moar boost not revs.

Well it was more so done with the provision of future power, might as well have done the work while the engine was out, head off etc..

One day I might want to go T88 and 800rwkw

[donmik]

Agreed Scotty, in this case it did make it worse, and we knew it would...

But the motor was built with race in mind, although its street driven!

Having said that, in my opinion and to a certain point I believe bigger is more effective for race purposes...

The motor has been done for future modifications pending...

As we would much rather work with changing bolt ons then removing and re working the engine later in life...

Ps. I totally agree about reving an rb, but what the customer wants the customer gets!

[ARTZ]

Lol..just read hybrid return flow...that won't be helping..

[blah_blah]

Lol..just read hybrid return flow...that won't be helping..

Its a normal intercooler just the attached piping is return flow

Sort like this pic I found on google

So if Scotty where to fix up some of the bends it might be better lol?

As im going to assume its the angle of the bends not the length of the pipe that might be the restriction?

Is hybrid intercoolers any good? Dont know much about them