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I've been watching this thread with a lot of interest, great to hear the results you are getting and the lack of problems (your fuel lines haven't melted yet :).

Just wondering, with all the more advanced timing / less knock, does that change your turbo choice at all?

I mean if you had (on a RB26) a Garett 2860 (2560) -9 or -7 and were aiming for 330awkw, would you simply squeeze more power out with the advanced ignition timing?

And would this completely change the power curve or would it remain similar?

Or would you want to go for a larger turbo like a -5 to take advantage of the more power?

I'm planning to run -7 or -9 on an unknown rebuilt motor (don't think its forged) but not for 6-9months, and E85 should be possible by then ;)

i think you will still have the about the same lag that you would have with pulp 98... the smaller turbo would be the way to go IMHO.

there is only so much timing can do for lag

I tend to agree with the latter line of thinking. Smaller exhaust housing size to keep the response right up there, but push the maximum out of the compressor with E85 and ignition timing to help.

I downsized my exhaust housing because I didn't like the lag and was content to aim for low 300's vs. the mid 300 potential of the larger housing - and it looks likely that E85 will give me mid 300's anyway :D

I tend to agree with the latter line of thinking. Smaller exhaust housing size to keep the response right up there, but push the maximum out of the compressor with E85 and ignition timing to help.

I downsized my exhaust housing because I didn't like the lag and was content to aim for low 300's vs. the mid 300 potential of the larger housing - and it looks likely that E85 will give me mid 300's anyway :D

What about the fact that, as mentioned here many times, you need to use more E85 compared to 98, this would create more exhaust gas's and then the smaller exhaust housing would create a restriction?

What about the fact that, as mentioned here many times, you need to use more E85 compared to 98, this would create more exhaust gas's and then the smaller exhaust housing would create a restriction?

I disagree. why.. I don't know.

What about the fact that, as mentioned here many times, you need to use more E85 compared to 98, this would create more exhaust gas's and then the smaller exhaust housing would create a restriction?

I tuned a BF F6 with the usual mods, was making 347rwkw on BP98 on 15Psi of boost, changed over to E85 and we ended up with 398rwkw on 17psi. The car actually ran 412rwkw at summernats.

From what I've seen it requires %28 more fuel to get to the same AFR as BP98. Its obviously a much slower burning fuel(as most alcohols are) so in only applying the fuel changes to the tune the boost crept up about 3psi over the pump tune. The XR6T's run about 12deg total advance on 15psi on pump with the right mods and I was able to advance the timing another 4degrees and add 2psi of boost. More timing netted no reward so I left it at that. I could have leaned it out but the customer was happy at that.

My thinking is that with good fuels you can choke the exhuast side up (put on a smaller housing) without loosing any power. Remember your still flowing the same amount of air on the cold side to get to the required horsepower you just need more fuel as the specific density is less and so is the rate of vapourization. The other thing to note is that exhuast backpressure reduces with greater ignition timing so choking up the exhuast side on good fuel may yeild exhuast backpressure equivalent to a larger housing on pump fuel with less advance.

Overall it took me about 10min of tuning on E85 to realised this stuff is good. If the fuel system is large enough it will get results similar to that of VP109 - which is about $200 per 20 liters.

I tend to agree with the latter line of thinking. Smaller exhaust housing size to keep the response right up there, but push the maximum out of the compressor with E85 and ignition timing to help.

I downsized my exhaust housing because I didn't like the lag and was content to aim for low 300's vs. the mid 300 potential of the larger housing - and it looks likely that E85 will give me mid 300's anyway ;)

I agree that having good response is all good, but traction becomes a real issue if its too snappy, RB25det (Lee's) car is a good example, try getting him to lower the boost, yeh right, no chance!!

I tuned a BF F6 with the usual mods, was making 347rwkw on BP98 on 15Psi of boost, changed over to E85 and we ended up with 398rwkw on 17psi. The car actually ran 412rwkw at summernats.

From what I've seen it requires %28 more fuel to get to the same AFR as BP98. Its obviously a much slower burning fuel(as most alcohols are) so in only applying the fuel changes to the tune the boost crept up about 3psi over the pump tune. The XR6T's run about 12deg total advance on 15psi on pump with the right mods and I was able to advance the timing another 4degrees and add 2psi of boost. More timing netted no reward so I left it at that. I could have leaned it out but the customer was happy at that.

My thinking is that with good fuels you can choke the exhuast side up (put on a smaller housing) without loosing any power. Remember your still flowing the same amount of air on the cold side to get to the required horsepower you just need more fuel as the specific density is less and so is the rate of vapourization. The other thing to note is that exhuast backpressure reduces with greater ignition timing so choking up the exhuast side on good fuel may yeild exhuast backpressure equivalent to a larger housing on pump fuel with less advance.

Overall it took me about 10min of tuning on E85 to realised this stuff is good. If the fuel system is large enough it will get results similar to that of VP109 - which is about $200 per 20 liters.

Hi Rob82, which side of the fence are you sitting on, do you think smaller or larger turbo than whats been tuned for 98 is better! lets say for the road anyway?

I agree that having good response is all good, but traction becomes a real issue if its too snappy, RB25det (Lee's) car is a good example, try getting him to lower the boost, yeh right, no chance!!

Hi Rob82, which side of the fence are you sitting on, do you think smaller or larger turbo than whats been tuned for 98 is better! lets say for the road anyway?

smaller

I agree that having good response is all good, but traction becomes a real issue if its too snappy, RB25det (Lee's) car is a good example, try getting him to lower the boost, yeh right, no chance!!

Hi Rob82, which side of the fence are you sitting on, do you think smaller or larger turbo than whats been tuned for 98 is better! lets say for the road anyway?

Damn straight boost stays where it is......In saying all that i reckon the larger rear housing would be nice with E85 a touch more linear (theres no way i would consider it on 98).

I agree that having good response is all good, but traction becomes a real issue if its too snappy, RB25det (Lee's) car is a good example, try getting him to lower the boost, yeh right, no chance!!

Hi Rob82, which side of the fence are you sitting on, do you think smaller or larger turbo than whats been tuned for 98 is better! lets say for the road anyway?

For street use - I would always go with more response/torque than top end horsepower so smaller turbo or smaller hot side or both.

My thoughts are that you should select a compressor that will flow enough for the desired horsepower. The selection of the exhuast housing has alot to do with the fuel being used as you can generally make the same horsepower on a better fuel with a smaller hot side than on pump pump fuel with a larger hot side, this way your maximising torque/average power. Turbo selection has alot to do with exhuast back pressure. The more the backpressure the more the stress on the engine but if your fuel is good enough to put up with it than its not a problem.

Bigger turbo's genreally mean more horsepower at a higher rpm which means redesigning the engine package. Are the cams big enough, will the head flow enough, will I need more cubes for the power to be usable etc etc.

Interesting debate so far, it will be interesting to see if some of these results are fed into something like the turbo thread...although I guess there's not many people using E85 so not many results yet...

Personally I'm thinking what would be the difference on a RB26 between Garett 2860-7 and -9 or would a smaller turbo be more appropriate for the E85?

In regard to the more fuel argument, even if you do get more fuel in there, the cylinder's the same size so the exhaust gases would be the same volume (unless more volume of air was in there) or would it be less because you know have more fuel and less air?

I never was that good at understanding engines ;)

I posted this a few pages back, have a read. The only thing i will say is that E85 will clean all the rust and gunk out of your fuel tank and system so you will need to replace the fuel filter a few times in the first thousand kms or so.

http://www.tamparacing.com/forums/green-mo...anol-myths.html

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