weber,header,cams - Toyota Nation Forum : Toyota Car and Truck Forums

drozy88d · 01-20-2005, 05:33 AM

I've got an ae92 with a 4af. I had been running a weber 32/36 dgv, header, 2.25 inch exhuast all the way back for a while and the car ran fine. I recently installed a set of 244 degree cams (a mild cam). The car runs good except it has a really rough idle. I know that this is the effect of being "lobed". I was wondering though if I advanced my timing if it could help it to idle a little smoother. I already have the timing advanced 12 degrees, but I heard if you go to high, you will burn a head gasket. How high is too high?

Flashmn · 01-20-2005, 10:08 AM

Yes thats because of the lumpy cams, 12degrees without or with vaccuum advance, if its base timing its too high. if its with vacuum advance its not too high. It wont necessarily burn a headgasket if its too high, it might break pistons, pistonrings, as its knocking.

Pineapple · 01-20-2005, 10:49 AM

Its detonation you have to worry when advancing timing.
Increase idle a bit?

automatic · 01-20-2005, 06:23 PM

The pulsing created by the cams may be messing with the advance, if you're using a vacume advance.
Try it w/out the vacum advance, I've had to raise the idle also on some of my cars, just under 1,000 rpm wouldn't be too bad if it helps to make the idle liveable.
Have you made any adjustments to the mixture screw?

gasman · 01-21-2005, 03:55 AM

just a quick question about you car. i was just wondering how much difference the carb and the exhuast did to you car over stock.

drozy88d · 01-21-2005, 04:19 AM

I do have a air/fuel mixture screw and I have adjusted it to where it is supposed to be. Last week I increased jet sizes and that helped a little. I increased my primary and secondary mains along with my primary and secondary idle jets, I have not jetted up the air jets yet would that help maybe? My timing is set with the vacuum advance disconnected. The only reason I ask is that I've heard people talking about how they can smooth their idle out by advancing the timing to say 18 degrees with performance cams installed. I was just curious to see if this will infact help, but I don't want to risk malfunction.

On a side note, the exhaust and weber did help, but the cams really helped a lot. I was very impressed with them even though they are a mild cam. When you put the weber on, you basically do away with all of your emissions crap. I've heard that just by getting rid of the emissions crap you gain around 5 horses just with that. Then you add in the exhaust and carb and your not doing to bad.

So flashman, basically I will have to live with the rough idle? I have adjusted my idle up to around 900, but the car wants to diesel when I turn it off so I have it around 650 which is what the recommended idle is. Also I was thinking of investing in an msd ignition. I don't know if you have any experience with these, but if you do maybe you can recommend a specific model to me. Thanks guys

Flashmn · 01-21-2005, 08:30 AM

Quote:

Try it w/out the vacum advance,

That would make it alot more shittier to drive.You'd have to advance it alot and at top end you'd detonate.

Flashmn · 01-21-2005, 08:34 AM

Quote:

So flashman, basically I will have to live with the rough idle?

yeah thats what you have to live with when you have rough cams. You'd have to have about 1000rpm idle to get it "smoother". You're dieseling because you're running too rich, lean it out and you'd have a better running engine. You're masking the problem with an overly rich mixture.
MSD ignition wouldnt help at all. You wont get any advantages over the stock ignition, you'd be running a 2D ignition map (RPM advance only). With the stock system using the vacuum advance, you'd be running a 3D ignition map (RPM and Vacuum advance). Infact I'd advise you to forget about MSD and use the stock ignition, it would be better all around performance.