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Anyone Tried E85 With A Gtrs On Their Rb25 ?

discopotato03
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discopotato03 Grand Master

discopotato03

Posted
Posted

I was just thinking about RB25s and GTRSs getting to around 250 odd RWKWs with supporting mods , and wondering if E85 would push a bit further to say 270 at the treads .

I suppose the limiting factor with a GTRS would be its 0.64 AR GT28 turbine housing , I'm wondering if E85 gives lower combustion temps and EGTs and if so can a bit more exhaust flow for a given turbine housing size .

Anyone using E85 and a GTRS in their Skyline ?

Cheers A .

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I was running a simple stage 1 sierra bushed highflow, 250wkw at best limited by knock to around 18psi. With the e70 I could run much more boost and timing gaining 50wkw at 20psi. The compressor didnt have much more in it though. I assume the GTRS would be similar, possibly able to run more boost than my highflow.

I used to think it was best to max out a smaller turbo but I realized the pressure in the manifold was just too great and not allowing the cylinder to empty of exhaust properly. I guess this is where the extra torque comes from when going to a larger rear housing or turbo?

Lithium Grand Master

Lithium

Posted
Posted

Have thought about that, but it still feels mechanically mean - smallest I'd try that with would be a GT2835. Having said that, have been really interested to see how a stock turbo would go on the generally accepted "safe" boost level on E85 :ninja:

scotty nm35 Grand Master

scotty nm35

Posted
Posted

Im now running the stock M35 turbo, similar to an 0p6 34 wheel on Eflex atm on a temp tune. From 180kw on petrol to 225 on ethanol but it noses over as soon as I hit stall, 4000 rpm. Very responsive, too much so. I would hate to know the pressure in the exhaust manifold, it must be over 60psi.

ARTZ Grand Master

ARTZ

Posted
Posted

I though exactlty the same disco that cooler EGTs would somehow solve the isssue of haivng too much exhaust gas there in the first place..I was going to run my little turbo on e85, but as Scott said, trying to push that much gas through the rear end, although somewhat effective, is also self defeating and probably harmful to your system in general.

In my case I thinks it would be better to simply swap out the turbo and be able to make the same power on PULP, you may gain a little lag but the power would be more effective and better for your engine as a whole. Plus PULP is everywhere :)

joeyjoejoejuniorshabadoo Grand Master

joeyjoejoejuniorshabadoo

Posted
Posted

I would peg 280ish from a gtrs on e85

No one even dreamed 300+ was possible from a 2835 a couple of years back... So much so that when I did 320 some people called BS

Dan chin's old highflow hit 290rwkw on ethanol

You are looking at about 15% above what a given turbo is known to e capable of at th usual boost levels

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I would peg 280ish from a gtrs on e85

No one even dreamed 300+ was possible from a 2835 a couple of years back... So much so that when I did 320 some people called BS

Dan chin's old highflow hit 290rwkw on ethanol

You are looking at about 15% above what a given turbo is known to e capable of at th usual boost levels

15% would be the gain with no extra boost. All depends what the tuner is comfortable with at the end of the day.

The stock turbo only made 1kw extra going from 17 to 18 psi but made another 100nm so even if the power drops off torque can still be improved. Not bad for a tiny ceramic wheel imo.

PM-R33 Grand Master

PM-R33

Posted
Posted

Man I would LOVE to give mine a hit on E85 and I definetely will as soon as we get it here. Would be interesting to see how far it can be pushed.

Would also make things a lot safer for me with the nitrous. Will hopefully have my car back on the dyno soon to see how what she is making these days with the gas.

Harey Veteran

Harey

Posted
Posted

So do we know the pressures in the manifold are dangerous using a 250rwkw turbo on 98 to make 270-280 on E85? I am running a very responsive hypergear turbo that makes ~250rwkw as well. My plan was to keep the responsiveness and add some more mid and top range by adding E85. Surely if I was to keep boost around 18psi it would be ok.

Whats the difference with SimonR32 running 25psi with a much larger turbo with an ethanol blend fuel?? Surely he would have quite high manifold pressures as well??

Is it the EGT's or the manifold pressure that we are mainly concerned with?

gotRICE? Veteran

gotRICE?

Posted
Posted

Having said that, have been really interested to see how a stock turbo would go on the generally accepted "safe" boost level on E85 :ninja:

Anyone you know that might be interested? I know someone that has some 555's "lying around" :)

ARTZ Grand Master

ARTZ

Posted
Posted

So do we know the pressures in the manifold are dangerous using a 250rwkw turbo on 98 to make 270-280 on E85? I am running a very responsive hypergear turbo that makes ~250rwkw as well. My plan was to keep the responsiveness and add some more mid and top range by adding E85. Surely if I was to keep boost around 18psi it would be ok.

Whats the difference with SimonR32 running 25psi with a much larger turbo with an ethanol blend fuel?? Surely he would have quite high manifold pressures as well??

Is it the EGT's or the manifold pressure that we are mainly concerned with?

EGTs and manifold pressure are basically related, responsive turbos usually have small rear housings to help spin your turbine wheel faster..

Problem is it will only flow so much.. More power = more exhaust gas..Try pumping too much exhaust gas through a small housing and it gets red hot.

It also backs up and gets forced back into your combustion chamber which is the last place you want spent exhaust gas when you are trying to pump fresh air in there..

Harey Veteran

Harey

Posted
Posted

EGTs and manifold pressure are basically related, responsive turbos usually have small rear housings to help spin your turbine wheel faster..

Problem is it will only flow so much.. More power = more exhaust gas..Try pumping too much exhaust gas through a small housing and it gets red hot.

It also backs up and gets forced back into your combustion chamber which is the last place you want spent exhaust gas when you are trying to pump fresh air in there..

Yes and then how does this change with E85 or other higher octane fuels? Is it not making more power out of the same amount of air? Or is it just enabling your engine to work the turbo harder without experiencing detonation?

My head is not working too well this afternoon!

scotty nm35 Grand Master

scotty nm35

Posted
Posted

EGTs and manifold pressure are basically related, responsive turbos usually have small rear housings to help spin your turbine wheel faster..

Problem is it will only flow so much.. More power = more exhaust gas..Try pumping too much exhaust gas through a small housing and it gets red hot.

It also backs up and gets forced back into your combustion chamber which is the last place you want spent exhaust gas when you are trying to pump fresh air in there..

Exactly, the gasses actually make their way back into the intake on valve overlap I have been told, thats why they carbon up. Not the best way to make powah, still it works. The ethanol just gives me a false sense of security. :)

scotty nm35 Grand Master

scotty nm35

Posted
Posted

Yes and then how does this change with E85 or other higher octane fuels? Is it not making more power out of the same amount of air? Or is it just enabling your engine to work the turbo harder without experiencing detonation?

My head is not working too well this afternoon!

My opinion, ethanol makes more power due to the lazy way it burns, right through the piston stroke, which in turn makes more torque. That's why you can pump so much timing in without going backwards or detonating. As the exhaust is cooler and less dense (less carbon?) it actually causes more lag than a petrol tune I have noticed.

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