On 87 or 91 octane all cars will knock with minimal alcohol injection going

The amount of alcohol we are using is a #7 jet which makes a very modest knock threshold improvement

Again the reason why we use the smaller jet now is before when we started with the original huge #15 jet we (David Buschur, SMC and I) relalized that a pump failure or system failure on the alcohol would result in engine failure

It was calculated that a #7 jet would give us 90% of the power benefits while assuring that in most cases IF the alcohol system failed the car would still be rich enough in the tune to survive long enough for the driver to relalize that a problem existed

The tunes on the #7 jet are intentionally left on the rich side so that if the alcohol kit fails you are still in the mid 12/1 a/f ratio area and the car wil survive. In fact many tuners I have seen tune evos at mid 12/1 a/f and the cars seem to hold together. Probably beuase the ecu pulls so much timing there is hardly any cyl pressure left.

In tuning with the # 7 jet you can approach a C16 race gas tuning parameter with ignition timing but the car still will knock if the timing is adavnced too far - particularly on 91 octane

In fact even on 121 octane VP Import and alcohol injection my own Evo can and will knock if timing is pushed too far

On a car on 91 octane with a #7 jet you can pick up pre-ignition knock as well with high boost on the stock turbo as there is plenty of heat in the turbo discharge air and these high inlet temps and significant exhuast back pressure create a knock prone situation

The alcohol only goes so far at reducing charge temps which an become very high on the stock turbo when you push the boost

Experiencing knock while doing an initial tuning run is normal and part of what I look for to create a saftey margin

While maximizing power delivery with a given set of mods is always satisfying that path leads to the enevitable conclucion that more motors will fail - particularly with the stock pistons. The fact remains that the stock pistons are very weak and will not take seious knocking. My discussions with most of my customers have shown that the vast majority want MOST of the available power with a very good and cautious margin of saftey left on the tuning table.

Even on my race Evo I follow the same approach as I do with my customers - conservative, safe tuning - reliable.

My experience has shown that agressive tuning methods make little of no apperaciable power gains when tuning with a stock ecu which will retard ignition timing if the tuning is set too agreesive. In dozens and dozens of case study examples i have retuned the agrssive lean tunes of other tuners and unlocked additional power and TQ by running the car richer and with less timing advance.

My personal recomendation is that the last 10 whp you can get by pushing your tune is not worth it if it takes years of life off your engine.

Is that extra 1/10th at the track worth having the car blow up and needing to have it towed home ?

 

Al and Abner,

I am happy with the tunning, I have absolutely no complaints there, the car is faster.
Before I did the retuning with the Alcohol I ran a best of 12.483 but that was one night with 3 or 4 gallons of VP99oct(race gas).

My best 1/4 time before on just straight 91OCT was a 12.610, I also ran a few other 12.6s on 91OCT in the past.

The summary here is that I definately dropped a couple of tenths on the 1/4 mile after the alcohol, I did a 12.5, 12.4 and a 12.5 the issue here is strictly the trap MPH, I honestly thought I was going to pick up an extra 2MPH at least but I didn't.

The interesting part is that I trapped at least 15 times higher trap speeds on 91OCT and 91 plus 99 than with the alcohol install.

I am sure this is just a illusion, I could only ran at the track 4 times that day, wind was blowing slighty in the opposite direction.

Me and Slowcar are going to the track on the 13th(Firebird), I am switching to Methanol but I hope to increase my trap speed.
Running in Tucson 12.4 on 91 is very difficult, trapping 109 at this altitude on 91 is also difficult.

I say don't worry guys, I hold on until Buschur releases the Evo 9 20G, I will run my car at Firebird Phoenix and I will switch to methanol and if needed I'd drop some 99OCT and we will see

 

Which boost gauge do you use now?

Also - I would suggest that you get a boost pressurized leak test done of the turbo and fmic pipes to dignose and parasitic leaks. I am confident that your car is capable of a very low 12 if not high 11's if the boost is set at the right level and with god traction.

BTW - did you find any sucess with the two step launch?

 

AL,


I got the Defi Imperial gauge(PSI reading). As far is the step launche control, No it was not connected,so i did not use it.

The more I think of this issue the more I understand it was more like bad luck and far from ideal conditions. Slighty windy day,track wasn't prep'd(as usual here at SIR),
I only ran 4 times. I am almost positive I could improve in the near future.

 

That particular boost gauge seems to consistantly read very high which means your boost can be lower than you think.

What was the indicated boost level when you went to the track ?