Question about my dyno graph (4AGTE)

[Bazda]

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[turbo4agte]

On BP 98 Pump Fuel at 20psi.. no timing advance

One problem could be you actually need to tune your ignition curve.

It needs some aggressive ignition before boost, and a gradual retard to redline. Your probably cheating yourself out of 20kw right there. I had a friend running 20 psi in a 20v 4AGTE AE92 with Megasquirt tuned at 10 degrees constant throughout, and it felt really slow in comparison to people running a tuned ignition and much less boost.

[Bazda]

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[turbo4agte]

I've always ran BCPR7ES which are copper. But you get the idea... the stock 5 heat range platinum plugs need to come out if thats what you have, and you need to tune your ignition better.

[GUN METAL]

all this talk of boosted 7A.s is getting me excited, can you guys post your dyno curves and engine specs in the Dyno results thread please

[Bazda]

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[turbo4agte]

When its done (probably sometime around December) I will...
Until then you can only watch my build up progress in my AE86 log.

[abently]

264 Cams of similar spec on a 2L DOHC Engine is holding back power from a 450Hp Turbo @ 6500rpm. So you see why I'm very sceptical that a ported 4AGTE can actually max that Turbo out.

Boost is just intake back-pressure, not MAF.. lol.

Btw, an easy way to skimp on going a bigger wastegate or better in/out piping transition, is to run more Boost.

Anyhow, you should start with the simple/easy things first. Get a proper tune, it will pay itself back within the year with the amount of fuel you save. Sort the clutch and ignition if you need to and then if your still not happy with how late boost comes on, upgrade to TRD 264 or 272 High-Lift cams and matching valve springs. You will have to play with the cam timing so it will be the most expensive upgrade, in terms of parts and tuning...

[oldcorollas]

but it is not about maxing out the turbo??

do you think going to 272's will bring on boost earlier than the current cams? by "high lift" do you mean the 7.9, 8.1, 8.35, 10, or 11mm lift?

so why does he need bigger cams again? what if he doesn't want his rpm range higher?
it sounds like you are (half)waffling again

[abently]

Okay firstly its TODA Cams your after not TRD... sorry... its been a while.

Running TODA 264 10.3mm cams will bring Boost on earlier, more top-end power and won't change the powerband. C'mon, that's about as much cake you can have whilst eating it too.

You'll be surprised how quickly you become accustomed to your new found power and start looking more.....lol

Anyhow, suffice to say it will be a while before you get to this stage anyway.

Good luck with it though. You've got a good base to work from so you shouldn't have to too many headaches.

[turbo4agte]

For the most part a lower duration high lift cam will help spool the turbo quicker, but with only 264 duration and as much as 10.3mm lift, the abrupt opening and closing of the valve is more likely to actually have little to no effect on spooling the turbo earlier.

Either way... it doesn't seem he has any type of proper tuning, nor that he really even knows alot about what he's working with so far since he recently bought the car. So I wouldnt be worrying about cams, or running more boost for a long time. I personally would start with the basic troubleshooting, then retune, then think about upgrades.

[mic*]

Since youve only just bought the thing and it hasn been mentioned, have you done a service on it? Fuel filter...air filter, plugs. Your ignition setup sounds mint so i wouldnt gap down the plugs, just up the heat range one from factory spec.

Im in agree-ance that there is a fuel or ignition prob of sorts. PWR v AFR dyno & review ignition data logging if poss.

Bit cheaper than cams to start off with...

[Pure-SX]

Why is everyone mentioning cams? I havnt spoken of getting new ones?

[mic*]

I was having a dig with that bit... Neg rep anyone who brings it up again...

[oldcorollas]

edit: ahh shit.. here comes the neg rep

turbo4agte: agreed..

pure-SX: abently has a habit of making profound statements like "you need bigger cams" and then never backing it up with a reason... kind of like what another famous "member" does


abently, you know that the 10.3mm lift 264's have a larger duration at 50 thou than the 7.9/8.1mm ones? the powerband will change, unless you spread the centres. as well as what turbo said abotu it having little effect on the spool (free tip for you, if the engine is already pulling in as much air as it can with smaller cam, befor eboost, then larger cams, esp in 4A, don7t have a large effect.... like if you put a 6" exhaust instead of a 5" exhaust )

you forgot to mention the springs, possible buckets and possible head relief work need to fit the larger cams......

and forgot to mention why his power graph indicates that he needs larger cams....