Anyone had a MP computer without overboost protection?

[1FastCSX289]

In my old 87 Omni turdbox, I ran 16-17 PSI all day long with that MP computer....never had an overboost (yes, stock injectors and MAP, just leaning the heck out of it). I thought that computer was a fluke. Well, today I was out playing with the boost on the charger and I saw 19 PSI for a split second on my boost gauge. I thought I was dreaming so I cranked it up again and it shot right past 15 heading to 20......no overboost. This is a different computer, different gauge, different car.....no overboost on it. Anyone else run into this with an 87 MP stage 2 CSX cal?

[BadAssPerformance]

Yep. '87 MP Stage II LM FTW!!!

It will overboost if you let it sit above 18psi for a while tho...

[GLHNSLHT2]

the 85 MP computer I ran didn't have an over boost. Ran down the freeway for miles at 15-16psi on 803's.

[turbo84voyager]

I built a 87 SC for a friend and ran a MP computer. No overboost on that one. The strange one is my 91 shadow which is running 90 electronics (sbec) As far as i know the computer is stock and it does not appear to have overboost protection. I found this out when I hit 18 PSI when my wastegate froze.

[1FastCSX289]

Thats funny......I thought I was just lucky and got glitchy computers. So.....if I cranked up the fuel pressure on this thing, you think I could get 18-20 PSI out of a stock 88 T1 engine, with stock injectors?

[BadAssPerformance]

T2 injectors? might not fry it on 93 octane... might

[roachjuice]

i ran 18 psi with a 5th injector. the max i would run without the 5th was 16. i wouldn't dance too long like that though lol. like short bursts.

[86Shelby]

The MP Calibration in my GLHS would allow overboost for a while as well. I always seemed to run into it at the end of a nice long 4th gear pull on the highway.

[boost geek]

The MP Calibration in my GLHS would allow overboost for a while as well. I always seemed to run into it at the end of a nice long 4th gear pull on the highway.

I would hit overboost before I crossed the 1/4 mile line in 4th gear.

[Big_P]

You guys are making me wonder. I have an 89 LeBaron GTS and I couldn't get it to cut out via overboost either. Almost killed my motor a few times because of it!

I'm still not sure because the car has a host of other electrical issues.

[mo' parts]

i though i read somewhere that the MP cal's had a 3-5? second delay for overboost while the factory cals were instant.
my old csx stg2 would do the same thing, so would the glhs stage 2 i had in my old glh.

[BadAssPerformance]

Yeah its still there but a delay, and more than 2-3 seconds?

[Aries_Turbo]

just get some JY dsm 450's, do a cal and solder up one of those freescale 3-bar map sensors that i have sitting here in my drawer. almost as cobblejob as what you would normally do but alot safer.

Brian

[Aries_Turbo]

btw, does the new motor have the mitsu or the garrett?

Brian

[1FastCSX289]

just get some JY dsm 450's, do a cal and solder up one of those freescale 3-bar map sensors that i have sitting here in my drawer. almost as cobblejob as what you would normally do but alot safer.

Brian

Well, id like to get ahold of a set. Maybe ill hit up a j-yard sometime soon and go look. What did those injectors come in? Early 90's Talon and Eclipse turbos only?

btw, does the new motor have the mitsu or the garrett?

Brian

It has the garret......and I just got it working so now I have boost. The car feels awesome.

[Aries_Turbo]

i bet it feels awesome compared to the pop and fart blowby machine that it used to be lol.

90-94 talon/eclipse turbo. the blue ones are the ones you want.

i can give you a hand with setting up the cal. there is a new version for the 87 stuff based on the MP cal so it will have good idle.

did you use the turbo from the original motor or was this one a real T2? LW or big rod?

brian

[1FastCSX289]

I used the old turbo. Same thing. I had a hard time getting boost.....ive got about 6 hrs in diagnosing the no boost problem. Turns out to be the air filter getting sucked onto the air inlet pipe and the inside of the filter blocking off the air flow. DOH! Ive got boost now and ive only had it up to about 8 PSI, but it feels faster than the other motor at 14 PSI.

Its an 88 T1 motor from a CSX-T. So, thats a LW rod motor. I think im gonna start building the motor I took out with T2 rods and pistons......have it as a spare.