EvoIII 16g'ed

[JoeWagon]

Originally Posted by Whathits14

Stock fuel system will run poorly on a 16g...Knock will be a problem. The stock fuel system was made for a turbo that flows 290 cfm's versus the EVO III's 550. Almost a double in airflow there....The stock pump doesn't flow enough to run a 16g on 91 octane safely. It will run, but you can hit fuel cut pretty easy...Speaking form experiance here.

Most of what you said is good, which is not to do too much on an upgraded turbo boost wise until you can log the kind of things that destroy the engine. As said earlier, the stock 2g pump is good to 40lbs/min, which is well above 20psi on even the largest 16gs. When you can log IDC%, my turbo ran a 13.5 at high elevation on stock fuel, with 105% IDC. There are people challenging conceptual theories like the impossibility of going over 100% IDC at the track, the same way people ran 1gs to 10's on 550cc injectors.

Just busting your balls... if you can't log and can't afford to fix broken parts, it's good to stay below 15psi on the 16g. For the record, 2g stock boost is supposed to be 14psi.

Originally Posted by Nayr747

My boost is 15-16 so I'm guessing from what your saying that I should be getting a boost controller. I haven't taken out the BCS or anthing like that so why is my boost so high?

If you have mods on a T25 this is possible. That's the desirable boost so I wouldn't worry about it, even though boost controllers are pretty cheap.

Originally Posted by dsmodder

i hate the chinese

Hold your tongue next time, this is the only warning for racism.

[kjewer1]

Originally Posted by Whathits14

Stock fuel system will run poorly on a 16g...Knock will be a problem. The stock fuel system was made for a turbo that flows 290 cfm's versus the EVO III's 550. Almost a double in airflow there....The stock pump doesn't flow enough to run a 16g on 91 octane safely.

I know I sound like a broken record, but I highly recomend dropping the CFM arguement. It is a piss poor measurement of airflow. All turbos are not rated the same when it comes to volume flow. For mass flow, there is no room for error. Please stick to mass flow rates, like lbs/min, kg/sec, etc.

Also note that I said that a stock 2g pump IS good for 40 lbs/min, which is more than 99.99% of poeple ever actually hitting that. Me being in the .01 that has of course

Stock boost is nowhere near 14psi for a 2g!!! The acuator on the t-25 is set around 10-11, with a possible 13 with the BCS mod.

Actuator is 7-8 psi, BCS sets it to 14 psi. At elast 13 psi, on every stock 2g I have seen with a real guage. With the BCS mod I was spiking to 17 psi, and holding 16, on the stock boost control. With the stock BOV, it was 15 psi.

The flow difference is HUGE!! the stock t-25 will support like maybe 250 hp with a huge amount of supporting mods, which would have been better spent on a turbo upgrade. At 14psi, the t-25 actually starts to lose efficency and makes LESS power than at stock levels. The gases coming out of the t-25 will be very hot at these boost levels, and the "gains" are actually detrimental! The hot gas will expand and will actually take up more space than the air coming out of the turbo at ~11psi.

You are certainly not speaking from experience here. The t25 will do 250 whp with minimal mods. It doesnt take many supporting mods to max out such a small turbo. With a UICP, BOV, and boost controller, I ran 100 mph in the quarter on the T25. Stock pump. Stock injectors. Stock IC. No fuel control. Also note that I did this at 20 psi dropping to 15 by redline. On pump gas 16 psi is the most effective boost level to run. Less boost made less power, more boost didnt add any power, but it certainly did not drop power. This doesnt jive with what you said above Also note that any time boost is dropping with rpm (over 5500 rpm on the t25 at any boost level over 14 psi), you have either maxed out the compressor, or maxed out the turbine side (WG is blowing open frome excessive exhaust manifold pressure due to the restrictive turbo), the jury is still out. I should also mention that your last statement defies the laws of physics, since the gasses coming out of the turbo, regardless of pressure or temperature, will take up the same amoutn of space, since it is in a confined location and gasses completely fill thier container. The exception is in dynamic situations, but it still applies, just not linearly.

You don't want to run your injectors at 104%, mums the word on 80% for most injectors. The 16g can chew enough gas to take FULL use of a 190LPH fuel pump, which is rated for 400 Hp, which is the max a EVO III flows.

I do agree that 100% IDC is the max you want to go. Any more than that and you are leaning out. But, if you are tuned too rich, say 10:1, and IDC goes to 110% and leans you out to 11:1, odds are you are still not going to knock. So it depends on the state of tune. You can max out 950s on a T25 if you run it rich enough For the record though, I ran into the 12s on stock injectors over 100% IDC, low 12s on 660s at ~110%, and into the 11s with 850s over 100%. I've had the 950s as high as 90%, but I am upgrading to 1600s to get back down to ~60%.

16g will def creep, so get out that die grinder and go about 1-2 inches into the o2 housing. Works wonders.

Porting the O2 housing actually does very little unless you enlarge the flapper, which I recomend avoiding if you plan to run ~25 psi on the turbo. See my site for more info, and past posts for info about the 34mm flappers blowing open limiting boost to ~19 psi at high rpm.

Also, another problem with the EVO is going to be HEATSOAK. at 16psi, you will heatsoak very quickly, so plan on getting a upgraded intercooler (supra smic is good, front mount is usualyl better...either is waaayy better than a stock one)

What gains did you see on the supra sidemount? I didnt see any with a 16g. Picked up a couple mph on pump gas though.

Not picking on you specifically, just posting on these points because I feel I have some decent personal experience with them over the last 5 years.

[TsiTalon9587]

Originally Posted by 95 GSXracer

I do agree that 100% IDC is the max you want to go. Any more than that and you are leaning out. But, if you are tuned too rich, say 10:1, and IDC goes to 110% and leans you out to 11:1, odds are you are still not going to knock. So it depends on the state of tune. You can max out 950s on a T25 if you run it rich enough For the record though, I ran into the 12s on stock injectors over 100% IDC, low 12s on 660s at ~110%, and into the 11s with 850s over 100%. I've had the 950s as high as 90%, but I am upgrading to 1600s to get back down to ~60%.

Which is exactly why my tune is safe. Yes I did make it to 104 IDC%, butr with regard to what Kevin said, this is why I am ok as far my air/fuel ratio. I was in the low ten's (estimated A/F as per DSMlink). Thus, when it did lean out, and only for a small while at higher rpm's, My margin of safety was still there.


PS: You beat me to the airflow arguement. I knew that was going to be coming as soon as I saw CFM.

[milton666]

lol, wow this thread has got way confusing, it's interesting to read all this stuff though, maybe ill learn something. but still im a little confused, give it to me in dumbass terms please (yes/no/or do this dumbass) with my mod list, what psi should i set my boost at???

[96spyderman]

Originally Posted by dsmodder

i hate the chinese

DUDE...not cool!!!!


I agree.. this topic is very informative but yet above my comprehension as for tuning!!! Kinda worries me for when I want to start boosting high... like 18psi and over...