550whp+ with stock internals

[M3 Muscle]

I plan on eventually taking my setup near the max potential of the turbo. I think that will be somewhere between 550-600whp. With that said I plan to use my stock bottom end S52 to hold the power. I know it's only a matter of time until it blows, but what do I need to do to get it to last a while? George posted the below statement and I was hoping to have people elaborate on this.

but.. if someone is looking to make 550whp on Stock Internals it is capable, but.... you will run the risk of bending the connecting rod upon the quicker spool of the 35R.

What is the safe low end and midrange boost limit that I need to watch? When can I throw full boost to the motor (or start increasing it)...after the peak torque of the motor?

[LukeG]

I'm having a hard time figuring out how the rods would be affected differently at 3k rpm at 1 bar than at 6k rpm at 1bar. Is that what George if implying? The actual compression ratio should be the same at any rpm as long as ignition timing/fuel and boost are the same. Or am I completly wrong to think this?

[pbonsalb]

I am interested in this question, too, as I start my conversion from 450+ rwhp Vortech to turbo. Until recently, the T4 GT35R had seemed like the first choice for the approximately 500 rwhp that is safe with stock rods and a 0.140 HG, but from what George and others are writing, a bigger turbo like the GT4088R may be safer for such a motor due to the slower spool (but if slower is better, why not just get a journal bearing T4 GT35R or use a 1.06 housing?).

For the GT4088R, is a PT undivided housing recommended over the standard housing? Is an 0.85 housing recommended over an 0.95 for a stock rod and 0.140 HG engine?

[GG///M3]

I dont know, but I remember Cardcounter's car lasting a good while with a gt35r t3(6xxwhp). Honestly I wouldnt wanna run more then 450whp on stock internals.

[jfdmas]

I made 550whp for quite some time with my sc61 which i would say has the same spool characteristic maybe a little less, however i wouldnt think 2x about reliability until mid 600whp. Id imagine that the rapid change in engine speed is extremely harsh on stock rods.

[milKt]

So throw some Eagles in it (properly sized, of course)
and run the GT35 to your hearts content.

I'd be interested to see JUST how many members here
have bent a stock rod at 500-550 whp.

POLL:

[ICS Performance]

I plan on eventually taking my setup near the max potential of the turbo. I think that will be somewhere between 550-600whp. With that said I plan to use my stock bottom end S52 to hold the power. I know it's only a matter of time until it blows, but what do I need to do to get it to last a while? George posted the below statement and I was hoping to have people elaborate on this.


What is the safe low end and midrange boost limit that I need to watch? When can I throw full boost to the motor (or start increasing it)...after the peak torque of the motor?

The 40R loaded it in 4rth of 5th will will make full boost around 3700 - 3800 RPM, the 40R comes on VERY smooth and pulls like HELL on the Top end. The 35R lights right up and puts enormous strain on the Factory rods.

I built a Turbo M3 last year, Tubular manifold, Built Lower end, OBD 2 Set-up T-3 GT35R 1.06 Housing, 3.5 Turbo Back Exhaust... What a car spooled quick and pulled very hard on the top end! 600+whp on 20 PSI - the torque was flat like a book shelf! 580 RWT insane car, power everywhere.

[gstuning]

I made 550whp for quite some time with my sc61 which i would say has the same spool characteristic maybe a little less, however i wouldnt think 2x about reliability until mid 600whp. Id imagine that the rapid change in engine speed is extremely harsh on stock rods.

the engine speed change has nothing to do with it.

What is happening is that there are two variables

amount of torque produced (cylinder pressure, airflow per cycle)
and
hp (torque over time)

The primary problem being to much torque for a given power output. so by lowering the mid/low end torque you can run alot more power safely.

So by creating a powercurve that keeps a set maximum amount of torque you´ll be fine. Say close to 450lbs@wheels torque@any rpm would be a benchmark of no rod bending or head lifting.

300whp@3500rpm - 600whp@7000rpm

The 450 number I´m just using as a point, not to be taken as possible.

[LukeG]

Ok so what George was reffering to was going from 0psi to full boost happening much quicker on the 35r. I can see that. The rapid change from 180wtq to 500wtq could be quite stressfull.


My suggestion: custom cams to smooth out the tq curve. Take out the massive peak tq that s50/52 cams tend to make.

[black bnr32]

That would be my guess as well - the more rapid change in tourque of the 35r.

Slightly OT: Could one play with the EBC settings to significantly smooth out the torque of a 35r set up? How much adjustablility is there? I never really played with it on my last turbo car.

[ICS Performance]

Ok so what George was reffering to was going from 0psi to full boost happening much quicker on the 35r. I can see that. The rapid change from 180wtq to 500wtq could be quite stressfull.


My suggestion: custom cams to smooth out the tq curve. Take out the massive peak tq that s50/52 cams tend to make.

Exactly..

That would be my guess as well - the more rapid change in tourque of the 35r.

Yup, been there done that, this is why Card Counters 2.8 Lasted so long, 2.8 small displacement, M3 Cams later spool, = Longevity.

[M3 Muscle]

The 40R loaded it in 4rth of 5th will will make full boost around 3700 - 3800 RPM, the 40R comes on VERY smooth and pulls like HELL on the Top end. The 35R lights right up and puts enormous strain on the Factory rods.

I built a Turbo M3 last year, Tubular manifold, Built Lower end, OBD 2 Set-up T-3 GT35R 1.06 Housing, 3.5 Turbo Back Exhaust... What a car spooled quick and pulled very hard on the top end! 600+whp on 20 PSI - the torque was flat like a book shelf! 580 RWT insane car, power everywhere.

When did that T3 1.06 GT35R make the full 20 psi?

[gstuning]

Again, that is not the problem, that is not how materials are effected stress wise. I.e rapid stress, as long as the stress is below it´s yield strength.

It is the amount of stress.

More torque = more stress.

So high boost threshold and maintained max torque limit = longevity.

[NakedBeast]

Judging by the quality of work you've done on your other two projects, I bet you will. BTW: how are they doing?

[m3jasper]

the engine speed change has nothing to do with it.

What is happening is that there are two variables

amount of torque produced (cylinder pressure, airflow per cycle)
and
hp (torque over time)

Again, that is not the problem, that is not how materials are effected stress wise. I.e rapid stress, as long as the stress is below it´s yield strength.

It is the amount of stress.

More torque = more stress.

So high boost threshold and maintained max torque limit = longevity.

[ICS Performance]

When did that T3 1.06 GT35R make the full 20 psi?

3400 -3500 RPM in 4rth Gear, as soon as you rolled into it, she would spike and hold 20 PSI instantly!

[gstuning]

Explain how I´m wrong.

I´m going to enjoy this.

[black bnr32]

Hmmm that's correct too gstuning. But, I'm a little too lazy to crack open the text books to figure out the stress differences between a 35r and 40r setup. I suspect there are actual differences though.

[m3jasper]

Explain how I´m wrong.

I´m going to enjoy this.

I didn't say you were wrong, I'm agree with you hence the "I'm with stupid!". Just figured I'd use the simile instead of just posting "+1"...

[ICS Performance]

Hmmm that's correct too gstuning. But, I'm a little too lazy to crack open the text books to figure out the stress differences between a 35r and 40r setup. I suspect there are actual differences though.

No need, I have done all the research and testing for all of us.

[black bnr32]

No need, I have done all the research and testing for all of us.

And I hope to be and ICS turbo kit owner once the dust settles!

[highboostingm3]

Explain how I´m wrong.

I´m going to enjoy this.

That smiley is a funny way of saying, "I agree with this super smart guy above!"

Don't forget the GT35R is an entire unit! Don't forget wheels and compressor housing as well. Just changing the turbine housing doesn't make it more like a GT4088R. The GT35R 1.06 a/r (t3 not sure of t4 equivalent) would create quite the massive street car but I say the GT4088R would allow the car to be a lot more reliable for a lot longer time and be more friendly when you didn't want to get on it. Tire spin is fun at first...

[gstuning]

Ah.
That has to be the least obvious internet sarcasm I have encountered.

This is misinformation
"The rapid change from 180wtq to 500wtq could be quite stressfull."

And the speed to torque change is not something to consider.
Just the maximum torque at any given time.

[ICS Performance]

That smiley is a funny way of saying, "I agree with this super smart guy above!"

Don't forget the GT35R is an entire unit! Don't forget wheels and compressor housing as well. Just changing the turbine housing doesn't make it more like a GT4088R. The GT35R 1.06 a/r (t3 not sure of t4 equivalent) would create quite the massive street car but I say the GT4088R would allow the car to be a lot more reliable for a lot longer time and be more friendly when you didn't want to get on it. Tire spin is fun at first...

Even a 35R T-3 .82 Hot Housing (with a well prepared tubular manifold) could make 600 WHP and SPOOL.... LIKE Massive Torque! You will Def Need a set of rods to say the least.

[Maciej]

Ah.
That has to be the least obvious internet sarcasm I have encountered.

This is misinformation
"The rapid change from 180wtq to 500wtq could be quite stressfull."

And the speed to torque change is not something to consider.
Just the maximum torque at any given time.

Exactly, revolutions are completely irrelevant in this case.

Cylinder pressure is directly related to torque, therefore if a 35R and a 40R are generating the same rear wheel peak torque (i.e. cylinder pressure), then the rods will both bend.