felixblack1

I recently installed a TO4B with 45mm wastegate onto my series 5 rx7. I got it tuned at 14psi and it produced 248hp at wheels on a Dyno Dynamics. The turbo was from a friend who got 278hp on the same dyno out of his 13b.

I had porting, bigger pump/injectors but a top mount intercooler. Where as he had standard injectors, bigger fuel pump, and front mount intercooler (2 joined fc3 intercoolers). My question is why the larger then expected difference in power? I know the Top mount intercooler absorbs a lot of heat (especially when on a dyno), but the FMIC wouldn't be doing much better (when on dyno and adjacent to the radiator with a pissy dyno fan).

zyounker

The 20RWHP difference could be from alot of different places...


Here are a couple:
1. Different Ambiant Temp
2. The intercooler
3. The fuel map (how are you controlling fuel?)
4. The timming map (Again how are you controlling this?)
5. Porting (No engine is the same)
6. Exhaust (Are they the same?)


-Zach

felixblack1

-Both our cars are running aftermarket ECU running spark and fuel.

-I have an EMS and his is the Microtech

-The dyno room would you believe is climate controlled.

-Exhausts are similar (both 3 inch all the way, however mine has a resonator and empty cat). His turbo manifold had larger diameter steam pipe but I swear his boost up faster then mine???

-Tuned by same guy (he did mention better results could of been seen with a microtech, however i never got a straight answer as to why)

-Virtually the rest of the 2 engines are the same,

I know I shouldn’t whinge over 20 hp, but...
Thanks
Felix

zyounker

Well the differences you listed are enough to make a big difference..

If you are using an EMS then you are still probably using the stock MAF which is not the best.. an EMS also does not have nearly the resolution as the microtech.. A microtech can more finely tune an engine. Plus it sounds like your exhaust is more restrictive..


I would make sure you watch your A/F.. With only a 20RWHP difference you might be running close to lean.. Or possibly he is running rich...



--Zach

felixblack1

correct me if i'm wrong, but the EMS has a higher resolution then the Microtech. The EMS is using its internal MAP sensor (and TPS). Maybe you are thinking of a different ECU. The EMS Dual Sport is an Australian design and I don't think it has reached the US as of yet.
Both our A/FR are running fine.

zyounker

Sorry, my mistake.. When i think EMS it usually refers to a piggy back computer.. So it is a full ECU replacement?

Cool...


In that case i would look at some of the other areas & the tuning..


OR maybe that is ECM???

-Zach