1991 Turbo 306 coupe MS3/PiMPxs tuning adventure

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wiseguyk

Active Member
Sep 23, 2016
299
75
48
Florida
I got 4 shorter datalogs today driving to/from work running 11.1.8 with no changes. With the new tune and timing/fuel changes the bucking was pretty much gone! :banana:

If the rain isn't too bad the next few days I'll do some more driving and really try to replicate the bucking scenario in different gears.
 

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wiseguyk

Active Member
Sep 23, 2016
299
75
48
Florida
Wow, I can't believe I've been driving the car almost daily for over two months since I last posted on here! Time flies when you're having fun I guess huh? :p

The car has been running really well and is a freaking blast to drive. Man, there's nothing like the feel of the boost kicking in and the radical pull the car has now. It brings a huge smile to my face every time I get on it!

Since my last update, I've done a few things. One was while trying to test and tune my boost control solenoid, I figured out that it wasn't hooked up correctly. I did all that wiring before I had the car running and driving and could have sworn I did it right but I sure didn't lol :p It ended up that I didn't have the right pin connected at the ECU for the BOOST output, so it was an easy fix thankfully, just had to pull the ECU back out and swap to the correct one.

The same day I fixed the solenoid, I swapped out my On3 wastegate for a Tial MV-R unit. You can tell just looking at the two of them side by side that the Tial is much better quality, and it also came with a bunch of springs to allow pressures of anywhere between 4.35 and 21.75 PSI. Since I'm working with a stock block and only likely to be pushing 10-12 PSI max anyway, I went with the lightest 4.35 PSI spring.

What's really cool about running the lighter spring is that with a (now working!) BCS, is that I have a lower minimum boost PSI and bump it up from there in whatever conditions I want. The MS3 has boost by speed and gear options in addition to TPS/RPM so I can tell it to keep boost at spring pressure at lower speeds and/or lower gears to help me get more traction than before. By comparison, the On3 unit comes with a 7 psi spring (which would vary between 7-8 psi) so it was even harder to get traction with 7psi minimum.

@a91what Steve played around with it when he was down my way a few weeks ago and the car was notably more well behaved when we tested keeping it at spring pressure until > 40mph (or maybe it was 60?). I really want to play with these settings some more to see what I like best and what yields the best traction, because right now it's really hard for me to keep from spinning as soon as I go WOT. Sure is a blast to roast the tires in 3rd gear just by putting my food down though mwaahahaha :D