here is my thread i started about low comp..i need to do a leak down test soon.. with poll
https://www.evolutionm.net/forums/sh...d.php?t=127709

 

He said that because sometimes, when you don't know what you are talking about, it's best not to "try to help." Bad information is worse than no information.

 

Check your boost gauge for accuracy. I have a Defi that reads 3 psi high. Also the engine compression can vary due to the temp of the engine or the gauge. The key is to have a consistant number. If it is 150 all across then you are fine.

 

Having been tuned by the same person on that same dyno, I would also say that is low... do a pressure test and see if you are leaking boost any where.

 

as stated the mustang dyno reads considerably lower

 

That is weird, I was at FIS about 3 weeks ago. I have 272's, XEDE, cam gears and TB exhaust and I got 340whp/302tq on the same dyno. Something has to be wrong!

 

Exactly... I made 333whp and 317 ft lbs with a slipping clutch on that dyno.

 

Find out your A/F Ratio!! Check your compression again (make sure the car is cold otherwise it could vary result wise) only this time do it once with oil and once dry then post the compression!! Also who installed your boost gauge/what kind is it, I've heard of many people installing gauges and getting false readouts b/c the gauge is only as good as the install....lastly, as many already said check for leaks!!

 

Who's boost gauge is the tuner referencing? Boost is where power is going to be had or lost. Are you sure your running what you think?

I would look into your knock sensor output or just verify your ignition map values... you'll suffer a large loss in power with something wrong in this area.

Then verify your a/f's.....

If a similar car with different mods are run on the same dyno, what does it matter? your using the same measuring device? His car is still making less power than another vehicle with less mods, if I read the original post right....

 

... you said you have no boost leaks - how do you know this? Have you tested or are just assuming???

 

Are you still running the stock diverter valve? I just did a leak test on my car, and my stock diverter valve was leaking significantly at anything over 14 or 15 psi. That may be a place to look. I'll be replacing mine quite soon.

-Paul

 

I have the bigger injectors because my idc was 99.9% with a 4th gear pull. Plus I plan on changing turbos.

It reads exactly 150 on each piston. I did the test with the car warm. Never heard of doing it while the car is cold.

My boost gauge is an autometer and I put it in myself. I know I did it right. I dont know if it is accurate though.

He was readng it off of my boost gauge. He said when he would try to add timing it would knock.

Im running a 1g crushed dv. It should be able to hold the boost.

Thanks for all the help guys. Im going to do a leak down test like lots of yall suggested. Because I am just assumning I dont have a leak because my boost hit and stays steady. No spiking or tapering down.

I will let yall know when I find something out.

--Josh

 

Is your car laggy when off and during boost? I'm in a similar situation. It could be a vacuum leak. I'm doing a compression test this weekend and will see what the numbers will be. You might want want to try a different bov along with the leak test and see if that helps.

 

I dunno if it helps, but I made 272 whp on the Mustang dyno here with my mods on my sig, I did 207 stock.

 

This is a mostly related question:

If your boost gauge is reading where you set your boost, say 20psi, and holds it perfectly to redline, can you assume you don't have a boost leak?