Has anyone ever installed a new engine, dynoed it & seen a drop in HP with no changes? I previously had a Mazda reman in my FD which made a high of 310rwhp at 11.5psi. Engine mods were:

Stock engine & turbos
GReddy FMIC
Unorthodox main pulley
K&N cones
No cats with GReddy SP
PFS PMC computer @11.5psi

The o-rings went south on that engine & was rebuilt by my local rotary mechanic here in Jamaica, using new rotor housings as the old ones were in questionable shape (lots of corrosion in the water passages). Anyway, the engine drives good with no sign of anything being a shitty job (idles good, good oil press, cool running). However, when dynoed, only put out 270rwhp . Can anybody shed any light on my missing 40hp? Yeh, yeh, I know about temps, etc, but the running conditions were practically the same, weather doesn't change that much here.

BTW, for those of you that haven't checked them in a while, have a look at your radiator hoses. I blew my lower on the dyno! It just exploded like an over inflated balloon. Make sure it doesn't feel soft & spongy, but stiff & hard to squeeze.

Thanks, Chris.

 

How Many miles since the rebuild?
I noticed that it my rebuilt keeps getting stronger even after 10k miles - it is noticably quicker now than after the 3k mi breakin period.

Also it is possible that the previous side housing were ported and the new ones aren't or that they used T-II housings insted of rew's the rew housings have larger ports.

 

This is probally insignificant but ill pos anyway.

I remember that car and driver had a porshce. That was for a long term test and it had more horsepower when it was time to turn it in than when they got it. only problem is i dont think it had like 20 hp more..it was like 4-6 cant remember for sure.
later

 

Thanks guys. I forgot to mention that I had 10k miles on the engine on the last dyno run (270hp).

Anyone else like to add your .02?

 

For you listed mods, the first dyno HP was way too high and most likely was in error. The current one reads more realistically.

 

Hmmmm....Jay (RecKleSs) is making 302rwhp at the same boost press. & he's even using the stock IC!

 

HMMM..Yeah, I agree with Chuck, that previous dyno has got to be too high... wait until it breaks in some more to get another look at it. I don't think you'll see 40 but you'll see a gain. Maybe 10?

 

Ok guys, thanks a lot, I'll monitor it & see how it goes.

Another thing I could use some advise on. Despite that I posted 11.5psi, I'm actually boosting more on the street. Using an Apexi AVCR, I hold a solid 13.5psi to redline. After turbo transition on the dyno, the boost slowly bleeds off to about 11-11.5psi at redline, so actually I'm not seeing what the engine is supposed to be putting out. Can anyone suggest a way to maintain the boost on the dyno? Increasing the AVCR duty cycle doesn't help.

 

bump

 

bump, bump

 

If the dyno run was made in 3rd gear use 4th instead. The dyno does not load the engine up as much as running on the street. The same affect as 1st or 2nd gear runs do not pull as much boost as 4th or 5th.
The lower gears and the dyno allow the engine to rev faster and thus the engine outruns the tubo's ability to keep up.

I do not know of anything that will help the turbos spool more on the dyno than on the street.

 

Yeah, I did realize it was a matter of loading on the engine. The run was made in 4th. Oh well, I'll probably never find out how much power my car is really making