Blacktop 4AGTE pistons?

[matt dunn]

Apart from your choice of fuel.

Steve

No.

Can run a high comp turbo on 91.
just have to tune the timing accordingly.
But you do need consistant fuel.
can't tune it on 98 and then run 91.

[KinLoud]

Thicker head gasket can reduce/eliminate the squish areas between the head and piston. Squish is one important factor in reducing tendency to detonate.
To quote corky bell "do not turn your turbo charged motor into a low compression slug"
To reduce/stop detonation you can retard ignition timing and/or change cam timing - do your homework on this.
Also make sure you have good efficient intercooling as the charge air temp has a big effect on likelihood of detonation.

[Mr Revhead]

Hell we ran a 3SFE Turbo motor with reasonable boost on near 12:1 comp ratio as an endurance car years ago. Mr Revhead would remember that.

endurance race car, and his mums daily driver!!

[Rookie]

When i said if detonation was a problem then I would fit a thicker head gasket, I was talking after I got it running and I couldn't get it to run right nomatter what timing or AFR were used. As for eliminating squish area, thats not really a problem seeings as a black top has next to none anyway., not to mention that when people put ZE pistons in them it makes it null and void because the pistons don't get near close enough to utilise it.


I hear what you are saying about making sure its tuned right.
Dave

[sergei]

When i said if detonation was a problem then I would fit a thicker head gasket

Thicker head gasket increases detonation due to reducing squish effect (by reducing swirl and creating hot areas).
Best way to lower CR is changing the pistons. If you don't plan to change the pistons do not fit thicker head gasket but reduce the ignition timing, if you have problems with detonation.

[Rookie]

did you not look at the pic, or read what I said? not to mention that multi valve engines don't have swirl anyway. So while squish would help prevent detonation by creating a more uniform air fuel mixture it wouldn't increase swirl, and besides blacktops have SFA squish area.

Dave

[shihad]

endurance race car, and his mums daily driver!!

thats signature worthy material made my day.


my mates silvertop turbo running ze pistons exhaust valve use to just nick the piston when warm (so im told) just be wary of the valve cuttouts.

[KinLoud]

Rookie - we are all trying to help you. It's more polite to says thanks and then ignore whatever info you feel doesn't apply to you.

If you do fit silvertop pistons with a blacktop head, be sure to check valve clearances... I have a blacktop head that was damaged when it was fitted to a silvertop block ( several valves broke off!)

Ken

[Flannelman]

Basic Full Throttle Timing RULES.

1. Advanced timing will lift power and economy and reduce exhaust gas temperature by making better use of the burning fuel.

2. Too far advanced timing will reduce power, promote pink/detonation.

3. Retarded timing decreses power, economy. Exhaust gas temp, CO and HC emissions increase causing havoc with exhaust valves and catalitic converters.

What Effects Timing? (My thoughts on most to least)

1. Load
2. Combustion chamber design
3. Boost/Compression
4. Type of fuel
5. Amount of fuel
6. Type of engine material


Rookie, Nice port work.

[Rookie]

Hey guys cheers for the info, I wasn't being rude, its just that that topic had been covered already.
Ken, do you think the extra lift of the black top cams caused the damage? was it the intake of exhaust valves ? I would have thought that the fly cuts in the silvertop pistons would have been in the right place, going by this pic they are.


Dave

[sergei]

Hey guys cheers for the info, I wasn't being rude, its just that that topic had been covered already.
Ken, do you think the extra lift of the black top cams caused the damage? was it the intake of exhaust valves ? I would have thought that the fly cuts in the silvertop pistons would have been in the right place, going by this pic they are.


Dave

Extra lift is not a problem, as I used Black top cams in silver top, and silver top remained non-interference.