Some of it is of course relative to fuel, but I use as an example my car when it was equipped with a Green, S1s, header, stock intake, 780s and 3" TBE. I ran it at 30psi on 92 octane with no additives, timing was 1* at peak torque and 9-10* at redline (8k). I sold literally the entire setup to one my friends here (Ryon) and he changed one part, the intake manifold. When I retuned the car he was able to run exactly the same boost, timing at peak torque but it would now suddenly accept 13* out the top.

When the parts were on my car the EGT would get to about 1550, his is 1450. The header would glow by redline in good light and his doesnt even start to change color when in the dark.

VE plays more to do with how much timing you can or cannot run and have "safe" EGTs. Fuels such as E85 burn cooler and the EGTs directly reflect it even in non boost situations like cruise (300*F less). My current setup on the 3586 at 29.8psi (2bar) runs 2* at peak torque and 11-12* at 8k and the header doesnt change color at all. I purposely keep the timing low at peak boost to keep the bottom end together and it still is very happy both EGT and overall stresswise (no knock, no head lifting, etc.).

One thing to keep in mind about timing is as you approach MBT (about 19* in an Evo) and cylinder pressure increases vs rpm vs timing you hit whatever peak power you are (i.e. peak cylinder pressure) going to make. Lets say for this example its 500whp. Back the timing up 2* from MBT and you'll lose 2% (I recall, possibly incorrectly) but HALVE the cylinder pressure. So for 10whp in our example engine we have reduced stress by 50%. I'll take 490whp if it lasts longer

Hope some of that was in english

 

This is on the right path.

I think some people think that boost numbers are like dynosheets and it makes you cool to say you run XX boost.

I remember one idiot that posted that they run 45psi holding 30psi to redline on an Evo X turbo. (which is smaller than the stock 8-9 turbo) Let alone impossible...

Its an epeen thing.

Reduce the boost level, add back in the timing and watch the car get faster.

 

I agree on a smaller turbo, with larger turbos I dont think its quite as clearcut. On a stock IX turbo it seems that best power is really probably about 24psi tapering to whatever. There is more to be had above that even on pumpgas, but the difference between 23 and 26 on a hot day in the dyno can be as little as 14whp as I discovered last night in a 90* dyno cell .

 

You're lucky then. Our dyno weather station read 101*F today and it sure as hell felt like it too.

With current turbocharger technology, yes larger cutting edge turbos are able to more efficiently supply higher boost levels at lower intake air temps which help deter detonation and knock at boost levels unheard of for pumpgas just a few years ago.

 

If any of the comments are for me about running more boost just cause it looks better, I understand all that fully. My car DOES make more power on pump by upping the boost, for some reason it just will not take timing but it will let me up the boost without really getting anymore knock. Im just doing it to bring the power to where I think it should be...

 

Haha this is funny.

You think the reason people run 30 psi on 93 these days is because of turbocharger technology advances? Uhhhmm... no. About 3 years ago nobody on this board would ever in a million years consider running over 22-23 psi on 93. Now it is common on a 35r / Red type all out build.

The turbos haven't changed... tuners just finally took their skirts off.

Boost increases yield more gains in cylinder pressure than timing. But obviously if your adding boost and not going faster you need to run a lower boost level.

 

I've melted a turbo. I've tuned dozens of lancers so it wasn't a rookie mistake. It was caused by high prolonged EGTs from going down to zero and negative timing with cams. This is on a track where I'm in boost 19 out of 20 minutes. For track driving 0 degrees at peak is definitely not adviseable, whether its normal or not. As a matter of a fact, I even melted the inconel. Google inconel... that's hard to do. Despite the settings for "max power" you should not run ANY LESS than 3 degrees at peak torque IF YOU ARE TRACKING YOUR CAR. Again I say, if you are just streeting it the car will handle -4 degrees with no problem. The car can handle bursts of high EGTs but prolonged power (at the track) WILL melt components.

 

Yes, I mean at peak torque. Even on a great tune the car is going to see a little knock whether real or not, and it will pull a little timing so if you're at 5 minimum at peak torque then you won't get into a negative situation. Since following this golden rule I've had no more problems. Before this I've melted every exhaust part.

 

i know you are used to bigger HP but 14 *FREE* hp sounds good to me.

 

You said you were running negative timing on track? How negative? Have any pics of what you burnt up? How did the pistons look?

 

Umm, yes. Why isn't the Greddy T67 turbo kit the best seller?

Its because it's old technology.

Where was the HTA compressor wheel 5 years ago?

How about the Billet HP6262?

They didn't exist.

Advances in technology has allowed some serious boost and performance with today's turbochargers.

 

Ya but take the 35r... 3 or 4 years ago nobody was running a 35r at 30 psi on 93. Now they are. No technology change. I don't think anyone thinks an HTA wheel is a big difference from a normal Garrett wheel. Very modest diff.

Yes the efficiency (heat of charge air) of a turbo at a given boost plays a role in tuning... but obviously it is the increase in cylinder pressure from more boost that is the real limitation in terms of what you can do on a low octane fuel.

I just think it is disengenuous to say it is turbo charger tech that allows the typical 30 psi on 93 type Evo these days. When in fact it is because tuners have gotten bolder.

 

I mean TTP... imagine you are back in time to 2002 or 2003 when Evo's first hit the USA. Don't you think you could build a 35R car running 30 psi on 93 making almost 600 hp (engine power) given the technology available at that time?

But instead this type of pump gas power did not really "hit" the boards until Buschur did it a year or two ago. I think it is because tuners finally decided low timing / high boost works and can be reliable.

 

No we still do not believe that Turbokits and turbochargers were as efficient as they are today. With banned vendors such as RNR and crappy turbine housings such as ATP "proprietary units, lack of many twin scroll designs, vband inlets and outlets, much has changed.

I still do not run over 25-26psi on standard 35R turbokits.

These HTA units however surprise the crap out of me in terms of pumpgas power.

 

That is odd because I tested going from a normal 35R to HTA 35R and the difference was extremely marginal.

Why do you choose to stop at 25 psi on a 35R? Don't you think many of Buschur's 30 psi / 93 octane builds are running around 0-1 degree at peak torque?