Can some one host a graph for me, we todd can't support it.

I need help analyzing a (big) dip in power on a turbo motor, looks like knock response to me but just want other opinions.

aaron

 

sure, email it to me, I'll host it for ya..

joe@locashracing.com

 

YGM

 

Here ya go..

 

THANKS!

looks like serious knock to me what do you guys think....

 

whats the setup? how much boost? Give us some info

 

dayum that **** is serious.

 

built h22 w/dtr stage V head. PT61 .70 comp & turbine housings 69trim P-wheel @18psi, PUMP GAS, AEM, ect...

the tuner is saying the dip is him letting off the gas, I disagree....
the car is now stricken w/ a blown head gasket I think this is why.

 

ttt

 

dood a 200 horsepower dip in a dyno graph isnt knock...... its him letting off the gas because you can see the red line run doesnt have the dip.

and i dont know who tuned your car but the a/f is all over the place.

 

The A/F ratio went over 13 in some places, even though it just a little but that could cause the end of the motor. Tuning doesnt look so great on the a/f, should tell him to smoothing the a/f ratio out and lower it a little bit...

 

A/F close to 13 at redline, no thanks

 

I think he's talking about the wave in the power band wright before he let off mid way through.

Also the 13A/f ratio especially at the redline

 

jdm,
I thought the same thing but look at the a/f ratio, usually the ecu cuts all power to the injectors when you let off the gas and the a/f disappears. In this case it just dips up to 13:1

Honestly I don't think it is a lift, and that is definitely knock response right before and after the dip. Besides why the hell would you get on it then get off totally then on again using a dyno jet it is not a load dyno...

edit : i am and have been unhappy with the overall a/f

 

*edit: My conclusions were wrong.


Modified by Muckman at 3:15 PM 12/6/2004

 

13:1 is pretty lean on a pump gas engine running 18psi

 

 

Why are you not reving it out any higher especilly with head work?

My stock head pulls solid up into mid 7's no problem...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by locash &raquo;</TD></TR><TR><TD CLASS="quote">Here ya go..

</TD></TR></TABLE>

dumb question but how are your plugs?

also another problem may be (and the reason why your headgasket blew) if the dyno.
In my experences, and i am sure people have different views, the dynojet dynos have to be tuned a little richer than other dynos like a mustang dyno. this is because the dynojet doesnt give an accurate "road condition" load. So when you are on the dyno with those pretty high afr's (as high as a little over 13 under full boost) the knock may be low or not present (also did you watch while the car was being tuned? As i tune a customers car i show them different points on the laptop so they can see what is going on and so they can learn how to tune there own car) but when you put the car on the street the load is or may be completely different so your afr may be .5 a point leaner. so now you may be sitting at 13.5 or 14.0 afr which is very high for a boosted application.
this could have caused detonation and blew your headgasket, but it is hard to tell with out seeing the motor.
Let us know what you find out

 

Im gonna say misfire, or your ecu through an itermittant code like o2, or map voltage, I had a problem with my car doing this if I got on it in third gear the engine light popped on and the car fell on its face, but then it disapeared and ran fine imediately.

 

that might be possable, I'll have to check the logs...

was not present for the tune.

the engine runs stock cams so that explains the early let off and remember it's an h22 not a b series. Plus it is graphed (on x) for time, not rpm.
by run 9 the torque was totally flat all the way out but the HG was done.


Modified by sw20T at 7:21 AM 12/8/2004

 

The blown head gasket could also be from the head lifting up. Turbo h22's putting down a good amount of power are known for it. My friend has blown 3 head gaskets within the past year on a turbo h22 that had a good tune.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sw20T &raquo;</TD></TR><TR><TD CLASS="quote">that might be possable, I'll have to check the logs...

was not present for the tune.

the engine runs stock cams so that explains the early let off and remember it's an h22 not a b series. Plus it is graphed (on x) for time, not rpm.
by run 9 the torque was totally flat all the way out but the HG was done.


Modified by sw20T at 7:21 AM 12/8/2004</TD></TR></TABLE>

I'm running stock cams and head aswell, it still makes power into the mid 7's atleast, and I have my WOT shift set at 8k. Haven't had any probelms after 3 years of running it liek that.

 

Since you are running the aem im going to guess that huge dip is caused by the Knock control is turned on. The ecu yanked timing due to a knock event that happened because of the lean A/F and possibly aggressive timing... just a idea.

 

The extra fuel right after that event would also support the idea of maybe the aem activating knock control...