So I've finally gotten around to tuning my car in for real now that I've gotten the car to stop breaking up on E85 (Lean it out. Who knew?) I've begun bringing ignition timing up gradually but I'm starting to wonder how far I can take this stuff. I'm at like 9-11 degrees at peak torque, hitting 18-20 by redline. I keep seeing trap speeds go up and have not seen knock.
So I'm wondering how far people have been taking their VIII's for a race only tune. I'm not worrying about street driven conservativeness. This is RACE only. AFR's are 11.7-12.0
Thanks for any input.

 

keep going as long as u dont lose power and ur not knocking im close to around where ur at on my tune lol how much boost are u running

 

You can keep adding timing until you reach MBT. That when its unsafe to add timing to an E85 powered car. Ive seen several highly respected tuners on here say that they have reached MBT before knock on E85.

I will say that your timing isnt much different then my car on pump gas at 30 psi

 

I'm boosting around 27 PSI, tapering to 22 ish. Past about 4K RPM it's what the stock 9.8cm VIII turbo will hold using a GM 3 port at 100% WGDC. I guess I'll see how far I can push it.
Also, whitey, what setup are you on that allows those numbers on pump? that sounds fun.

 

I'd say you are most likely pretty close to MBT up top and possibly past it at peak torque. Of course every car/mods/boost curve is different.

- Bryan

 

On the dyno, and I am sure GST will verify this, Evos dont make power past 19* in my experience. The most I have run (relative to load of course) at peak torque was 2-3* and still was making good torque per degree of timing. On some 35R cars it will be more I have noticed but generally its low till 6k, then jumps up significantly and is all in by 8k.

 

9-11 deg at peak torque seems high even for an Evo 8, but if you're seeing improved trap times after changing timing only in this rpm range and there is no knock, then you should be ok. I'd probably do some dynog testing to verify though.

 

I do peak in torque really high because I'm running GSC 280's (too much cam. I know) so according to evoscan's HP/TQ estimator, peak TQ is at 5800 or so RPM. I guess I'll be spending some time in a cornfield tonight and seeing what happens. Thanks for your opinions, maybe I was headed is the wrong direction. Any more input is definitely still welcome.

 

Use the excel spreadsheet dyno graph thing on here. Evoscan's RPM is off by 800-1000.

 

Ya thats a ton of timing for peak tq but if power isn't falling off then you might be ok.

Def check things over with DLL or JOT's dyno graph.

 

What type of turbo are you running and at what RPM does the turbo sing its song?

 

I couldn't figure out the excel dyno for the life of me, but DLL has a free 30 day trial so I got graphs. I'm on a VIII turbo 9.8CM hot side, TBE, BCS spiking 25 PSI, tapering to whatever the turbo will hold, GSC 280 cams, O2 housing, I think that's it for mods.




I tuned until my laptop was flashing warnings at me, it's basically roughed in but you can see a hole around 6000 RPM that I'll need to fill, which judging by adjacent cells, I need to add 2-3 dgrees of timing. Is it possible that my base timing is WAY off? Are there usable timing marks anywhere to check with a timing light?

 

bump up the smoothing factor to like 19 and it will take out those rough edges

 

wow.

 

The number you put in the ign table after all is just a number. The best way to find what spark your engine likes is spending a day on a dyno. The target peak psi CA˚ is around 13 - 14˚ ATDC irregardless to load, boost, and rpm, but is dependant on rod-length/stroke/bore.
You can find how close it is on a dyno, or on the road but you will need an accurate rpm log. But usually excessive demand for ignition advance (like 10˚ or more near peak VE) means other things are out of tune i.e., AFR, atomization, swirl, valve timing, bla, bla.. Usually at peak VE on VIII is about 3-7˚

One important thing to consider, never use knock as an indication of sufficient timing. If the octane is good and there's no knock, an overadvanced engine can easily melt the head or vaporize a crown with extreem CHTs without one count of knock