[Mk2] [Turbo] ats knock censor problem

[jjduffgts]

thought id let ye al know about my fooked engine because of the knock censor from ats racing.i popped a knock censor ages ago from bad fuel (95 octane)anyway i ordered a gm ats knock censor and fitted it.happy days ful power again but not for long she blew up a few days later.stripped her down and found piston rings broken,cylinders scored big ends gone.went and spent 10k on a forged rebuild fitted the knock censor again not knowing what was going to happen and 3weeks later i knew that somthing was wrong.stripped the engine again and found all the same problems again and more including pitting on the new forged piston tops.i knew after this that the timing was advanced too much and had caused too much heat in the engine.after alot of head scratching i found out that the rev 3 turbo never made it to the american market and the censor i fitted could not be read by the ecu thus advancing the timing too far and the rest is history.NOW ats racing advertise the upgrade censor for all revisions of mr2 turbo which is misleading for people who dont know this.detonation is severe after fitting this part and id like to advise anybody thats using this knock censor to make the correct ignition timing adjustments and use octane boosters.if anybody thinks im wrong in my analisis of this i would love to hear what they think might have caused the problem.good look and happy motorin

[paul_h]

I think you have more problems than the ATS knock sensor

The rev 1 which the american market got has the same bore and stroke as the later revisions, 86mm dia x 86mm stroke therefore the knock frequency that the sensor detects will be the same on both engines. People have fitted rev3 knock sensors to earlier cars with no problems proving that if the ATS sensor can detect knock on one engine it will also detect it on the other.

There has been a debate on the american forums of how sensitive the ATS sensor is to the knock frequency of the 3SGTE but from personal experience when running a standard engine on one it did pull the timing and the VSV lower the boost when i got a bit greedy with boost one day and the engine knocked.

It sounds like you have some serious issues with your setup and without knowing anything about it people will just be guessing, if you can post up a more detailied engine spec then we might be able to help you out

Detonation is ususally caused by bad timing or too much boost or too high temperatures so

1. if your running a standard ECU check the base timing and lower the boost or get better intercooling

2. if your running aftermarket ECU check the map itself and base timing etc.

paul

[jjduffgts]

thanks for your reply paul,you make sense in what you say but i cant think of any other reason why may engine did not detect the detonation in the cylinders ill give you all my details and mabey youll see something i dont.
1.bottom end
perfect crank balanced with forged crowler rods,forged pistons 86mil bore act 11lbs flywheel all assembled with arp studs ,full race big end bearings.
high flow oil pump and water pump.

2.
top end
hks head gasket,head ported and polished,standard cams,re shimmed.greddy timing belt.standard fuel system,standard boost.recon ct26(couldnt find a ct20)hks adj cam pulleys ,honed trottle pot.hks cone filter.

there is more but just iridium plugs and stuff like that.well hope you see somtin wrong here cause i cant figure it out.just seeing the pitting on the top of the pistons sent alarm bells ringing i only ever seen this in engines with automatic ignition timing.

thanks again
john

[Hellboy]

Did you ever get it on a DYNO to check the WOT fueling and the AFR across the revrange?

[jjduffgts]

helo again paul sadly i never made it to the dyno with the mr2 to check this because i was still running in the engine and didnt want to rev her too hard until there was 1k or so ran in.oh and forgot to say that i got the correct torque settings from ats at the time of fitting,this can be an issue.anyway ill build her again and see how it goes,can you tell me how
much to retard the timing by when running on 95 octane unleaded.have

read that 10 degrees before tdc works well and illiminates detonation.


regards
john

[bobhatton]

I think 10 degrees is the standard setting, thats what you should be at. What did you have your set to?

Bob