Finished NA-T, Bogging down at 6-8psi boost.

suprabones

New Member
Sep 12, 2007
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Hello everyone,

I just finished my "build" of a NA-T setup, let me 1st go over everything that is installed and then the problem.

Car: 88 Turbo supra
Engine: JDM 7mge (Did not have the money at the time for a new 7mgte) Ajusa HG, ARP Headstuds, 304SS 2.5" IC pipes, HKS SSQV, HKS Super mega flow intake, 440cc injectors, coilpack, CPS, stock turbo exhaust mani, rebuilt Ct-26 (no upgrade), 2.5" exhaust, Apexi N1 muffler, Basically all the stuff from a turbo engine are on the NA motor, with exceptions to the fuel pressure regulator.

That said, the car was a turbo model, so all electronics are turbo.

I am having a strange "bogging" issue at higher RPMS on stock boost, would the 7mge fuel pressure reg. cause this? Do I need to install the 7mgte fuel pressure reg. I dont think I have a boost leak, its boosting fine to stock boost, I am getting 6psi at 2700RPM.

Thanks everyone.

-Matt.
 

89supra7mgte

New Member
Sep 20, 2009
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colorado
the fuel regs are different start with putting that on. ou should have two knock sensors as well, one by alt and one by starter, n/a/ block only had one in center of other two locations. I also believe from looking at tsrm that the gte had a few other sensors on the water neck housing that the n/a did not. Do you have the correct pcv system set up as well? might not cause the bogging if not but might cause future problems.
 

suprabones

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Sep 12, 2007
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dumbo;1451123 said:
Tell me you have a wideband.

Also check our codes. How did you do you knock sensors?

I do not have a wideband yet, I am shopping for one as we speak. have only put the car in to boost 2 times, I am gonna stay out of it until the wideband arrives.

I have no codes being thrown. I have wired both signal wires in to 1 sensor. It is not a knock sensor problem I dont think, I can take it all the way up to redline in lower gear no problems and no codes.

89supra7mgte;1451319 said:
the fuel regs are different start with putting that on. ou should have two knock sensors as well, one by alt and one by starter, n/a/ block only had one in center of other two locations. I also believe from looking at tsrm that the gte had a few other sensors on the water neck housing that the n/a did not. Do you have the correct pcv system set up as well? might not cause the bogging if not but might cause future problems.

I am looking for a fuel reg to put on it. I dont have the correct PCV setup either. I actually just read some posts last night about routing the PCV back to Pre-turbo and post AFM.
 

suprabones

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Sep 12, 2007
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Ok so here is what I did today.. Did the KS re-wire, put a new KS in, re-calibrated my TPS, set timing to 10 BTDC... Still have strange bogging issue.. it bogs down right at 3k RPM, doesnt really want to go above it unless I go WOT and let the auto kickdown..

Perhaps its a AFM issue?? I am gonna take my car to work tommorow and drill / tap the block for a 2nd KS. Maybe that could make a difference.. Still no codes either..

Any suggestions?

-Matt.
 

dumbo

Supramania Contributor
Jul 16, 2008
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Do you mean no CEL, or did you actually check for codes. 2 knock sensors wont make a difference if your one is wired (correctly, NA-T, correctly)
 

suprabones

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Sep 12, 2007
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hottscennessey;1451913 said:
Wait. Breaking up or bogging? Which is it?

Well, Kind of both :aigo: The car seems to bog at 3000 RPM and drop down to about 2500 RPM and will make like a machine gun breaking up sound as I go higher.. Unless I go WOT and the auto tranny kicks down..

I know its strange.. :1zhelp:

-Matt.
 

suprabones

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Sep 12, 2007
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dumbo;1451922 said:
Do you mean no CEL, or did you actually check for codes. 2 knock sensors wont make a difference if your one is wired (correctly, NA-T, correctly)

I have checked for codes.. No codes and no CEL.. just steady blinking.

I think I am gonna pick up some Autolite coppers tommorow and gap them as per TSRM and see if that will help.

-Matt.
 

CRE

7M-GE + MAFT Pro + T = :D
Oct 24, 2005
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Denver, CO
suprabones;1451348 said:
I do not have a wideband yet, I am shopping for one as we speak. have only put the car in to boost 2 times, I am gonna stay out of it until the wideband arrives.

Once or twenty times... boosting without sufficient fueling can slaughter an engine in seconds. And you're doing all this without the correct FPR and no idea how much fuel is actually getting to the engine? :3d_frown:

suprabones;1451886 said:
Also maybe the plugs are causing the break up? They are about 1yr 2months old.

Wait... You're running the N/A plugs? Well, that could be the whole problem right there... the gap is WAY too big.
 

89supra7mgte

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Sep 20, 2009
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Is it a turbo tranny? i might be wrong but do believe the two are different? I have ran into "running problems" that were actually "trans problems" dont rule that out either. Specially if it is acting weird until it kicks down? I dont know the auto trans on these, but have come across an issue before where the car actually felt like it was missing at certain speeds because the trans was slipping and wanted rapidily go back and forth between gears up or down.
 

suprabones

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Sep 12, 2007
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New plugs in, gapped to specs in TSRM, NGK coppers. Throttle response feels a lot more responsive. Old plugs looked like I was running really fat.

Found a issue on why I am probably feeling a breakup, my #1 plug wire is worn down to the thread insulation.. I am sure it is arcing over and losing power.

On the note of the tranny, it is was the original turbo tranny that came in the car. 112k miles on it.. However it does sound really bad.. sounds like the bearings are going out in it.

Still no codes, and with the new plugs it seems to pull fine.. now its just not wanting to go past 3k RPM fast. Perhaps new wires will fix it..

suggestions?

-Matt.
 

BOOSTEDSUPRA

THE DRIVELINE GUY
Jan 4, 2007
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turlock, calif
sounds like a fuel froblem. unless... this "bearing" noise your tranny is making, is it only when your moving? or will it "whine" while in neutral. that doesnt sound like bearings, sounds like it is starving for fluid, wich will result in less pressure, which will cause the tranny to bog, and the car not to wanna move very good. been here done this.

pull the pan on your tranny, change the fluid. and check your kick down cable. if i remember right there is a diaphram that gets ripped, and the kick down doesnt work correctly, resulting in lots of power loss. my n/a did this, checked everything you are, and it was a pluged filter and the kickdown not working right.
 

ValgeKotkas

Supramania Contributor
Apr 14, 2006
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The FPR from turbo car was needed, at least that's what I've read from other threads.
Wonder what's the difference between a N/A and turbo one?
 

dumbo

Supramania Contributor
Jul 16, 2008
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Albera, Too Far North
I hope that bearing noise isn't (ball bearings in a coffe can). Get a wide band man before something breaks. Plus a GTE regulator, the epc does show that there different. Keep us updated, I'm curious my NA-T went last time at the track. Had GTE everthing.
 

suprabones

New Member
Sep 12, 2007
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Cleveland Ohio
BOOSTEDSUPRA;1453203 said:
sounds like a fuel froblem. unless... this "bearing" noise your tranny is making, is it only when your moving? or will it "whine" while in neutral. that doesnt sound like bearings, sounds like it is starving for fluid, wich will result in less pressure, which will cause the tranny to bog, and the car not to wanna move very good. been here done this.

pull the pan on your tranny, change the fluid. and check your kick down cable. if i remember right there is a diaphram that gets ripped, and the kick down doesnt work correctly, resulting in lots of power loss. my n/a did this, checked everything you are, and it was a pluged filter and the kickdown not working right.

The tranny makes a "whine" sound in park, neutral, or drive.. However the sound gets quite after the car warms up.. Think its a fluid starved tranny? I will drop the pan. and change filter / fluid.

Also I was gonna adjust the kickdown last night after reading this, the kickdown cable it stuck.. So I def. need to do some work on the tranny.

-Matt.