Got Over 400kw Atw?

[R31Nismoid]

^ eggsacary

[The Dan]

The LINK ECU plugin has had problems with factory ignitors due to the wasted spark and insufficient earth track inside the PTU to carry twice the load. Not sure if this is your problem but it would definitely be worth checking the ignition with a scope on the dyno.

We've fixed a couple of GTR PTU's now but now we just wire in a replacement like a Microtech X6 or similar

[Piggaz]

The LINK ECU plugin has had problems with factory ignitors due to the wasted spark and insufficient earth track inside the PTU to carry twice the load. Not sure if this is your problem but it would definitely be worth checking the ignition with a scope on the dyno.

We've fixed a couple of GTR PTU's now but now we just wire in a replacement like a Microtech X6 or similar

That makes sense. Unigroup got rid of my ignitor and replaced it with some box that lives in my passenger footwell. They did that went I jumped across to the Link.

[TiTAN]

But it's the E85 which allows you to dial in more timing. Which came first, the chicken or the egg? .

or as it supports it, turn on the antilag, cyclic idle, and remove the brake booster or get an electionic vaccume pump.

lag is now a non issue

[rob82]

You'll pick-up usually 200rpm at least from most results I've seen? And 200rpm is better than nothing.

But... My entire point is based around the fact that once the issues are sorted, he will have 20psi a lot sooner than 5000rpm like it does now, it'll be at least 500rpm if not more.

Hmmm I've seen the opposite - you will generally pickup power everywhere under substantial load but the boost will come on at a slightly higher rpm due to the higher effective load on the piston from running greater ignition advance. To a point the more ignition advance you run the lesser the exhaust energy you create.

[scotty nm35]

^ This man knows. I saw less energy off boost so the turbo took a little longer to spool. With a good tune it might pull up even with 98, with more compression it would blow it away though.

Not many tuners are keen to tune a high compression engine on e85, most I ask say i'm mad. lol.

[Piggaz]

^.

Can't say I've had the same results. EVERY tune on my own car the E85 has made more grunt everywhere AND boost is higher earlier.

Same car, tuner, dyno, turbos/setup/cam timing and in some cases same day!

That's on more than one turbo setup too!

[Hadouken]

Thats because your tuner is a guru

[rob82]

^.

Can't say I've had the same results. EVERY tune on my own car the E85 has made more grunt everywhere AND boost is higher earlier.

Same car, tuner, dyno, turbos/setup, tuner and in some cases same day!

That's on more than one turbo setup too!

Try retarding ignition timing by say 6-8 degrees from mbt on a STD gtr on pump and see how the boost threshold increase and the boost rises - obviously you will lose hp everywhere though.

Your doing the opposite by advancing the timing on e85. The one thing to consider is the ramp rate and the time on load before the ramp is started. Obviously with higher octane fuel you can safely run it at higher low rpm loads with less chance of knock for a longer period before ramping which may make the figures look better.

[The Dan]

Hmmm I've seen the opposite - you will generally pickup power everywhere under substantial load but the boost will come on at a slightly higher rpm due to the higher effective load on the piston from running greater ignition advance. To a point the more ignition advance you run the lesser the exhaust energy you create.

How is there a higher effective load on the piston from running greater ignition advance? The fuel is higher octane so it burns slower. The ignition is advanced because the engine needs to start the burn earlier to get the best complete burn in the cylinder. The cylinder pressure should be pretty much identical at equal hp outputs.

Shouldn't the load increase only once you get past the efficient timing range only?

[rob82]

How is there a higher effective load on the piston from running greater ignition advance? The fuel is higher octane so it burns slower. The ignition is advanced because the engine needs to start the burn earlier to get the best complete burn in the cylinder. The cylinder pressure should be pretty much identical at equal hp outputs.

Shouldn't the load increase only once you get past the efficient timing range only?

Yeah load was bad terminology - it should read higher effective work. Also just because the fuel burns slower doesn't mean it's flame propagation speed is slower. Not sure what your on about cylinder pressures but they are not directly related to hp.

[The Dan]

Yeah load was bad terminology - it should read higher effective work. Also just because the fuel burns slower doesn't mean it's flame propagation speed is slower. Not sure what your on about cylinder pressures but they are not directly related to hp.

I might be wording it incorrectly also

However, can you better explain how cylinder pressure is not directly related to HP?

[Lithium]

^ I am also very interested to know where he's coming from, or going with that....

[bigmikespec]

Peak engine torque will occur at max. cylinder pressure.

[mico]

how do u know that ?

[Mark-32]

The LINK ECU plugin has had problems with factory ignitors due to the wasted spark and insufficient earth track inside the PTU to carry twice the load. Not sure if this is your problem but it would definitely be worth checking the ignition with a scope on the dyno.

We've fixed a couple of GTR PTU's now but now we just wire in a replacement like a Microtech X6 or similar

Does the problem with the link sound like the problem I'm having and start at a similar rpm area to me? I'v just done a firmware upgrade on the vipec I'm hoping this may solve it but I'm doubtful

[rob82]

Peak engine torque will occur at max. cylinder pressure.

Not necessarily but close - there are too many variables to assume that peak torque occurs at max cylinder pressure. Most in cylinder pressure monitoring systems will look at average pressure across the cylinder pressure curve. But trying to derive an output for torque based on this isn't that easy you still need to consider the effecting moment on the crank.

So if you have the in cylinder pressure curve plotted against crank angle, you know the effective moment at each crank angle and the rpm you could derive a hp value.

So back to my initial point by retarding ignition timing you are moving the cylinder pressure curve further from the ideal point and also reducing the peak values - hence you are allowing more energy to escape into the exhaust system putting more work into the turbocharger.

[Mark-32]

Here's a couple of bids of the misfire

[The Dan]

Not necessarily but close - there are too many variables to assume that peak torque occurs at max cylinder pressure. Most in cylinder pressure monitoring systems will look at average pressure across the cylinder pressure curve. But trying to derive an output for torque based on this isn't that easy you still need to consider the effecting moment on the crank.

So if you have the in cylinder pressure curve plotted against crank angle, you know the effective moment at each crank angle and the rpm you could derive a hp value.

So back to my initial point by retarding ignition timing you are moving the cylinder pressure curve further from the ideal point and also reducing the peak values - hence you are allowing more energy to escape into the exhaust system putting more work into the turbocharger.

You're both wrong. Peak cylinder pressure happens at peak detonation

End story

[The Dan]

Does the problem with the link sound like the problem I'm having and start at a similar rpm area to me? I'v just done a firmware upgrade on the vipec I'm hoping this may solve it but I'm doubtful

No, it's usually a hard missfire but it is something worth checking regardless.

I would also check the coil charge time in the ECU as this is a very common mistake/problem