Stock boost I have no knock

 

once again on pump 91-92oct dont run over 21 21.5psi (safely)with addition of race gas having octane rating above 96OCT you can up to 24-25PSI.
MAKE SURE YOU TUNE IT/ FLASH IT FIRST

 

I’d have to say that’s not true. I just did some datalogging on my friends ’04 Evo. On his particular car we could’ve just cranked the boost to 24 or 25psi on the stock maps. They are so rich and conservative with timing that it’s no big deal. I ended up leaning out the maps more than 2 air/fuel points in the upper RPM regions from the stock map. I kept the stock timing map the same because I liked it. It keeps a bunch of the burn energy in the exhaust manifold which is ideal on volatile pump gas. We then started raising the boost until we could get just a little bit of knock. For some reason you guys worry a lot about the boost spike. Unless it causes knock ignore it. He posted above that it spikes to 25 and holds to 23. His knock count is between 1-3 at 6500 rpm’s or so. This is an insignificant amount. We could run 25psi on the car for drag racing no problemo. If your not knocking your not trying. His only mods are a Joe P MBC and a Buschur catback.

Also whats the deal with boost anyways? 24psi on stock cams vs 24psi on a set of cams is not the same thing. The fact that you are using boost levels as a criteria is showing me that you don’t have a grasp on what causes problems.

Now if your modding your car and aren’t watching your knock sensor your asking for it regardless of boost levels. I’ve seen stock DSM’s blow up on stock turbos and 14psi boost in nearly stock cars. I’ve also personally ran 26psi on pump gas in my very modded stock motored 1990 eclipse w/161K on the clock.

Furthermore ARP’s aren’t as necessary as everybody thinks. First putting them in one by one is a hack job. You can do more damage than good. Pull the head and do it right.


Have a good day....

danl
11.80 at 126 stock bottom end stock head stock cams

 

Please feel free to run 24-25psi on pump gas then - be my guest.

 

Well here's a log of the data. As you can see knock is not their and timing is climbing to redline. Tell me whats wrong with this tune?

 

all i have to say is, get a custom tune by a vendor such as AL. for example, when he tuned my car 3 weeks ago, he turned the boost up to 1.6 bar on pump gas and the a/f ratios are 11's. so all i can say is, keep it safe, stay at 21.

 

 

nothing. but all it takes is one bad tank of gas. dave buschur noted that you could run up to 25psi and not blow your motor on a conservative tune, but it wasn't recommended. there really is no benefit to it because you had to pull the timing back to do so. with a good tune on 21psi you'll find equal to or better benefits than running just the higher boost. just throw some alky in when running 25psi and you'll get the full advantage of running that type of boost.

 

agreed

 

double post..

 

Ok, sure. Go ahead and talk to me about saftey then educate me about alky injection. You are aware of how dangerous alky is aren't you? Skip through the detonation and go straight to preignition. Hello, are those my rods laying on the ground . Nothing like good ole' leaded race gas to coat the valves and to control burn rate.

 

MBC you can peak at 24psi and it tapers off to about 19psi. I'm tuned for it, but 24psi is a LOT of boost, the car doesn't like it on cold days (but it's the shop car haha). We can make the same power on 20-22psi properly tuned with the EBC. This gives you more control and a broader torque curve. Our Gruppe-S Stage 2 flash will make about 280whp at about 20-22psi if you have cams, fuel pump. Give us a call we can set you up

Cheers,

Gary
Gruppe-S

 

Why not Turbo Trix flash thats what i'm trying next time after a few more mods.

 

What everyone is speaking to is a "rule of thumb", not the gospel. You can run whatever boost is deemed safe in your logs (I am guessing that the OP is not logging at all). The problem will be "is your car safe for all conditions".

The answer is no. When you get the, random, really cold day in Sept. will you knock? When it's crazy hot outside will you run into a problem with detonation? I have played with my tunes quite a bit and also checked my logs and I can get away with a lot of timing and boost but the car is running on the ragged edge of very expensive problems. This isn't shown in my logs but obvious from experience (not much, mind you).

All I have to say is good luck and happy boosting.

 

+1

The bottom line is that if you're going to start messing with your tune (yes, turning up your boost qualifies), then it would be silly not to invest the ~$110 to get the Tactrix cable and Evoscan to monitor your Evo.

As you begin to push the outside of the envelope on the tune, you'll find that some Evos will respond better to more boost and less timing, others will respond better to less boost and more timing. LOTS of variables...

l8r)