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Discussion Starter · #1 ·
how would i go about increasing the rev limit? it seems to be a 4500rpm rev limit.. so it pulls hard for like 2 seconds then i have to shift my plans arent super extensive 14lbs of boost 20% over injectors and i want the rev limit to be like 5500. is it just a matter of of getting a tuned ecu?
 

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Discussion Starter · #3 ·
its not overboosting i know what that is.. it just pulls really hard till 4500 then its just goes limp like a fatchick just walked in or somethin.. and i havent been able to get it to rev past 4500..
 

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Discussion Starter · #4 ·
ok so i should prolly give you some more info on the car. its a 89 daytona shelby t2. i had to swap the turbo to a mitsu cuz the garret was toast. i just took it for a drive it wont rev past 4000 itll hold 7psi of boost while its hittin that limit. the only thing i can think that it could be is the o2 sensor. because its not hooked up. the mitsu i put in has a 3 wire o2 and the car is setup for a 4 wire o2 . could that be causing this?.. the timing and everything else is kosher so its gotta be the o2... although it wouldnt rev past 4k before i did the so idk.. help plz..

also its shows 21 and 55 but im pretty sure that means no codes
 

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I used to hit the stripe at 6100 rpm's in 3rd gear and the car was still pulling so if you are losing power @ 4500 you definatly have an issue.
O2 sensor is not even a player @ WOT.
WOT is a fixed parameter "open loop" mode.
Start by verifing all basics.
Cam/Ignition Timing
Fuel Pressure especially under boost
Vacuum/Boost leaks
TPS voltage is above 3.50 volts @ WOT.
Ignition system is up to par, a weak coil or excessive resistance cannot produce enough voltage with high cylinder pressure.
 

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Discussion Starter · #14 ·
well it had the whole top end regasketed by a shop so i dont think the timing is off.. and i dont think the exhaust is restricted because the turbo spools up really quick. it feels like something computer controlled.. it pulls super hard then it bogs out when i shift it pulls really hard till i get to 4k then bogs again... the first thing im gunna try is the o2 sensor i think its causing like a limp home mode or something stupid like that the only other thing i can think it is is maybe the hallaffect pick up?.. the car came with an extra one so i swaped it out didnt seem to make a difference. but it might at high rpms... it could also be the coil cuz it looks pretty old..
 

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just because a shop did the top end doesnt mean that the cam timing couldnt be wrong. i did a tbelt job on a honda the other day and the cam timing was off on that by 1 tooth( done by the dealer before) just goes to show you that just because you paid for the job, doesnt mean that accidents cant and dont happen, check and be sure dont ASSUME it right.
 

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Discussion Starter · #17 ·
well i should prolly check the timing but thats a whole lotta work im not prepared to do, im still recovering from the turbo swap i did.

but ill prolly do it tomorrow. any tips for making it ez to check?..
 

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Real easy to check.
First remove the upper timing cover and measure the cover circumference from bolt tab to bolt tab and then divide by 2 and mark that spot on the timing cover.
That will be the centerline which is also the centerline of the head.
Reinstall the cover and remove the spark plugs.
Rotate the crankshaft by hand until you are at TDC on a compression stroke with #1 cylinder.
Verify TDC by being sure the timing mark on the flywheel/converter is aligned with 0 on the timing marker.
At TDC the slot in the cam sprocket should be aligned with the mark you made on the timing cover.

Disregard the smaller line, the larger line is center of the timing cover and you can see where it aligns on the valve cover, that is centerline of the head.





 
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