Jump to content
SAU Community

Recommended Posts

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

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.

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

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 :P

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. :thumbsup:

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.

^ 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.

^.

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!

^.

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.

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?

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.

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?

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

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.

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

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

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • You won't need to do that if your happy to learn to tune it yourself. You 100% do not need to do that. It is not part of the learning process. It's not like driving on track and 'finding the limit by stepping over the limit'. You should not ever accidently blow up an engine and you should have setup the ECU's engine protection to save you from yourself while you are learning anyway. Plenty of us have tuned their own cars, myself included. We still come here for advice/guidance/new ideas etc.  What have you been doing so far to learn how to tune?
    • Put the ECU's MAP line in your mouth. Blow as hard as you can. You should be able to see about 10 kPa, maybe 15 kPa positive pressure. Suck on it. You should be able to generate a decent vacuum to about the same level also. Note that this is only ~2 psi either way. If the MAP is reading -5 psi all the time, ignition on, engine running or not, driving around or not, then it is severely f**ked. Also, you SHOULD NOT BE DRIVING IT WITHOUT A LOAD REFERENCE. You will break the engine. Badly.
    • Could be correct. Meter might be that far out. Compare against a known 5 ohm 1% resistor.
    • @Murray_Calavera  If I were an expert I wouldn't be in here looking for assistance.  I am extremely computer literate, have above average understanding on how things should be working and how they should tie together.  If I need to go to a professional tuner so be it, but I'd much rather learn and do things myself even if it means looking for some guidance along the way and blowing up a few engines. @GTSBoy  I was hoping it would be as simple as a large vacuum leak somewhere but I'm unable to find anything, all lines seem to be well capped or going where they need to be, and when removed there is vacuum felt on the tube.  It would be odd for the Haltech built in MAP to be faulty, the GTT tune I imported had it enabled from the start, I incorrectly assumed it was reading a signal from the stock MAP, but that doesn't exist.  After running a vacuum hose to the ECU the signal doesn't change more than 0.2 in either direction.   I'll probably upload a video of my settings tomorrow, as it stands I'm able to daily drive, but getting stuttering when giving it gas from idle, so pulling away from lights is a slow process of revving it up and feathering the clutch until its moving, then it will accelerate fine.  It sounds like I need to get to the bottom of the manifold pressure issue, but the ignition timing section is most intimidating to me and will probably let a pro do that part.  Tomorrow I'll try a different vacuum line to T off of, with any luck I selected one that was already bypassed during the DBW swap.  (edit: I went out and did it right now, the line I had chosen did appear to have no vacuum on it, it used to go to the front of the intake, I've now completely blocked that one off at the bracket that holds several vacuum lines by the firewall.  I T'd into the vacuum line that goes from that bracket to the vacuum pump at the front of the car, but no change in the MAP readings).  Using the new vacuum line that has obvious vacuum on the hose, im still only getting readings between -6.0 and -5.2.  I'm wondering why the ECU was detecting -5.3 when nothing was connected to the MAP nipple and ECU MAP selected as the source. @feartherb26  I do have +T in the works but wanted to wait until Spring to start with that swap since this is my good winter AWD vehicle.  When removing the butterfly, did it leave a bunch of holes in the manifold that you needed to plug?  I thought about removing it but assumed it would be a mess.   I notice no difference when capping the vacuum line to it or letting it do its thing.  This whole thing has convinced me to just get a forward facing manifold when the time comes though.
    • Update: tested my spark plugs that are supposed to be 5ohms with a 10% deviation and one gave me a 0 ohms reading and the rest were 3.9ohm<, so one bad and the others on their way out.
×
×
  • Create New...