dyno tuning comment caught me off guard

steviek · #1 07-11-2007, 04:41 PM

Well I decided today to get my car professionally dyno tuned. I have been trying to street tune it but whenever I change something I get another thing wrong etc and haven't had much help or success. So I called the place today and they asked the usual stuff like does it have engine management wideband o2 etc which It does and its all being logged with dsmlink. But then he said something weird he asked me if my boost controller was manual and I said yes and he said well its no good because you want to be able to spike boost and then taper it off? I was like well thats weird I thought you wanted to peak and hold boost pressure. He said that his is the way to make peak power??? I was caught off guard because I know lots of people who are running very fast cars with mbc's and I didn't think it would have any impact on tuning whether you turn the knob inside the car with a program or outside with a mbc. Seemed a bit off to me. Any input?

Blackcrow64 · #2 07-11-2007, 04:55 PM

I never heard of that being a better way. I always thought peak and hold was the best way to make peak power... ?

SilvrEclipse · #3 07-11-2007, 10:36 PM

I have been wondering the same thing. Me and a friend of mine dynoed our cars the other day. He drives an Audi TT and his boost curve peaked at 21psi at 3k but by the time he got to red line he was down to about 12psi. This confused me bc I thought that a flat boost curve would be better. I think we need Kevins imput on this one...

scottsee · #4 07-12-2007, 01:53 AM

I wouldn't pay or take your car to somone like that.... Gave up on dsmlink hu... Let us help you, whats going on??

steviek · #5 07-12-2007, 02:53 AM

Well I didn't give up on dsmlink its just that I don't seem to be making any progress on my own. I can't understand why I am getting knock at my "default" settings which should be a rich (approx 9.5:1) fuel curve. And when I add fuel it doesn't seem to help. And I'm using 94 octane here too. and you saw my logs it does look like the knock follows the A/F ratio perfectly which implies that it is because of the leaness but I'll be damned when I add fuel I have even gotten MORE knock.>????

scottsee · #6 07-12-2007, 11:46 AM

I remember that you were on stock enrichment and you were jumping down to 12.1 A/F after 4000rpm. There is a mechanical fuel issue, Injectors set incorrectly, BPF off, clogged fuel filter, pinched line, bad fuel pump, or a combination of any of those things.

A high hp guy around town is having the same issue on his fp3052, he sent off his injectors, replaced his afpr, changed his fuel rail, replaces his filter and still has to be in the + fuel enrichment just to get 11:1 A/F's. Just add fuel untill your knock goes away..

kjewer1 · #7 07-15-2007, 01:50 AM

Everything on his logs points to the WBO2 reading too lean. There is no easy way to know for sure though. The WBO2 should be trusted, but when you have 3-4 other pieces of data pointing at a single different AFR, it's hard to argue with them. But back on topic, the boost spiking thing is crap. Many stock cars do that, but it's only so the car feels fast (torque) but stays in one piece at high rpm for warranty reasons. Not performance reasons. In many cases the stock turbo can't even hold the boost the factory runs in the midrange, so you don't have much choice anyway.

Bottom line is more boost at high RPM equals more power, provided you are set up for it.

Not to mention that MBCs spike, not EBCs. So his statement doesn't even make sense in the first place. Either the guy is a tool or there is some miscommunication going on.

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