T04Z On Rb26

[Piggaz]

What's "full boost"? 10 psi or 45?

[Mick_o]

Should go around 20+psi by 4000rpm mate depending how well ya car is setup?

[Lithium]

On a 6262? I would have expected mid 4000rpm at best?

[cul8er]

I just don't want to sit there waiting for it to kick in like my old T78

[rondofj]

Mick probably meant full boost on E85 not petrol @4000rpm

[Lithium]

Yeah I figured that - any earlier than say 4300rpm on E85 with an RB26 would really impress the hell out of me!

[cul8er]

Earlier the better

[JH32]

I just don't want to sit there waiting for it to kick in like my old T78

or like the T04Z

[Mick_o]

I maybe wrong but I thought Jez's car went 21psi around 4100-4200rpm? In my experience E85 doesn't increase turbo response.

[rondofj]

hey MIck, how does your EVO compare to the R33 you had? I know very diff cars, but...your 33 was mental

Edited July 1, 2014 by rondofj

[Blackkers]

yeah E85 improves response but won't spool the turbo any quicker OR earlier in the rev range. ie, the turbo response characteristics are same same e85 vs ULP

It just means you can run stupid amounts of ignition timing

If I was looking to your power range I'd look at highmounting a FP HTA3582; although I think you just mentioned you've already got a twin scroll manifold and FP don't offer a TS rear housing.

[cul8er]

yeah E85 improves response but won't spool the turbo any quicker OR earlier in the rev range. ie, the turbo response characteristics are same same e85 vs ULP

It just means you can run stupid amounts of ignition timing

If I was looking to your power range I'd look at highmounting a FP HTA3582; although I think you just mentioned you've already got a twin scroll manifold and FP don't offer a TS rear housing.

Thanks mate yeah I have a Greddy twin scroll high mount manifold already

[JH32]

yeah E85 improves response but won't spool the turbo any quicker OR earlier in the rev range. ie, the turbo response characteristics are same same e85 vs ULP

It just means you can run stupid amounts of ignition timing

So ignition timing has no effect on spool?

[Lithium]

Turbo knows nothing about the ignition timing, it just knows how much exhaust energy there is - while I haven't measured it admittedly, I'd wager a cheeseburger than in terms of exhaust energy a car running 20degrees of timing on petrol will have a different amount of exhaust energy available to drive a turbo to one running E85 and 20degrees of timing at the rpm/load point. Can't overly simplify the comparison, too many variables to say too much but at the end of the day on E85 you certainly don't suddenly get a huge amount better (or worse) spool - though to drive the car it can seem that way.

[JH32]

in terms of exhaust energy a car running 20degrees of timing on petrol will have a different amount of exhaust energy available to drive a turbo to one running E85 and 20degrees of timing at the rpm/load point.

Agreed, and exhaust energy has an effect on spool. Then on E85 you have so much more headroom to adjust timing as against PULP, which has additional effect on spool due to a further change in exhaust energy. There are so many threads on the interwebz about timing versus spool, they can't all be wrong!

[Lithium]

You seem to have read what I said but not fully taken it in. I am saying the picture is way bigger than just timing versus spool, they are two variables in a much bigger equation - comparing a turbo's performance between different setups makes the results less and less comparable, whether it be cams/fuel/displacement/you name it so imho you just have to take it as a general indicator against other like setups.

E85 is awesome though, regardless of if the boost curve is (or isn't) favourable with E85 the power delivery tends to be nicer - boost threshold is not the most important thing imho... that is just one part of the puzzle that provides performance.