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need help with 4age 20v st not making power

Posted: Thu Oct 31, 2013 11:26 am
by dennisarodriguez1386
I jusy installed a 4age 20v st in my ae86 my prob is it feels like it has no power the motor is running blacktop itbs ecu and wireing it has a 10pound fly wheel and stage 3 act clutch and toda cam gears the vvt is not running and it feels like its n9t pulling at all now I seen people run vvt cam gears and toda cam gear mixed and wated to know if maybe my timing or something is off because am not making power is there any benefit to gain by not running vvt or should I just reinstall my stock cams pls help

Re: need help with 4age 20v st not making power

Posted: Thu Oct 31, 2013 12:13 pm
by yoshimitsuspeed
You would have to get your cam gears on a dyno for them to do any good.
Any way you cut it the VVT will give you more power across the range.
For troubleshooting you should put the stock gears on to eliminate variables. If you are running stock cams then I would just leave the stock gears on. Even if you run big cams I would hang on to the VVT as long as possible.
While you are at it double check your cam/crank timing. Once it's back together check your ignition timing.

Re: need help with 4age 20v st not making power

Posted: Thu Oct 31, 2013 3:13 pm
by burdickjp
Still have your AE101 ITBs? Throw them back on. AE111 ITBs are large even for AE111s. You're losing throttle modulation for likely no gain in power.
If you'd like, A Graham Bell talks about throttle sizing in "Four Stroke Performance Tuning"
You can also do CSA analysis and look into fluid flow with multiple restrictions. What comes out the other end of this would be that throttle openings over a certain ratio of WOT will not contribute to mass flow, which means you've reduced your throttle modulation, which means everything over a certain throttle position is worthless. I prefer erring on the small size with throttles. I'm running AE101 throttles on my AE111.

DO get functioning VVT back. Check timing.

Is your ECU throwing any codes?

Re: need help with 4age 20v st not making power

Posted: Thu Oct 31, 2013 8:39 pm
by dennisarodriguez1386
I am going to run stock cams gear and I dont know about codes because am running black top ecu what would be a good mild cam to go with so I can gain a little more low end power because my 16v pulled way faster and thanks for the help

Re: need help with 4age 20v st not making power

Posted: Thu Oct 31, 2013 9:31 pm
by yoshimitsuspeed
dennisarodriguez1386 wrote:I am going to run stock cams gear and I dont know about codes because am running black top ecu what would be a good mild cam to go with so I can gain a little more low end power because my 16v pulled way faster and thanks for the help


The BT ECU will output codes too. If it's not hooked up then that should be your first priority.

If your 20v is not pulling harder than the 16v across the range then something is definitely wrong.

Any aftermarket cam will help more in the upper RPM and quite possibly sacrifice at least a little low end.
If you want low end then stick with the stock cams.

Re: need help with 4age 20v st not making power

Posted: Fri Nov 01, 2013 5:21 am
by dennisarodriguez1386
The bt ecu is connected I just dont know how to test it it runs smoothly its just a st motor with bt itbs wires and ecu its got a 10lb flywheel and act stage 3 clutch but when I got it instead of stock cam gears it has toda racingd cam gears that delete vvt but he gave me the vvt cams now for some reason my 16v pulled alot harder then this motor for 1500rpm to red line for some reason this motor feels like all noise and no go

Re: need help with 4age 20v st not making power

Posted: Fri Nov 01, 2013 6:05 am
by onnaj
If it has stock camshafts then i'd definitely would try the stock cam gears. Vvt is giving you power across the band and when you feel something is wrong then going to stock is the best point to start imo.

Re: need help with 4age 20v st not making power

Posted: Fri Nov 01, 2013 6:27 am
by burdickjp
The factory service manual for the blacktop lists codes and provides instructions in how to get them.

Get it running right before worrying about changing to bigger cams.

Re: need help with 4age 20v st not making power

Posted: Fri Nov 01, 2013 8:26 am
by morgan
burdickjp wrote:Still have your AE101 ITBs? Throw them back on.

^and the ports are shaped differently, its not an even flow