Dyno# Twin Turbo GN running 16 lbs --pinging???

[daverr]

Dyno Numbers

hello,
recently i took my GN to a local dyno to get some base line runs. I made two runs on 93 octane ,which i think was a big mistake.I should of been on the safe side and run race gas. Well anyways i thought for sure the engine could easily run up to 6500 rpms.Power peaked at 5700 rpms than it Maybe missed or pinged causing dips in the hp curve(see above pics).Fuel pressure never dropped and peaked at 60 psi with boost.

1.So my question is what could cause this dip ,detonation, could it be tune, octane,plugs?????
2. Could the turbo cause this car to peak alot earlier than i expected (5700rpms instead of 6500)???surely there is more power to be gained at higher rpms, or no??
3. If i raise boost will it peak even earlier???
4. Dyno operator said AF was alot higher than he would feel safe with at 93 octane, whats your take??

Orginally i thought the turbos were 60-1 ,i was told the turbos look alot bigger than 60-1.here`s a pic of the engine bay

Engine bay pics

 

[John Wilde]

Dyno Numbers

hello,
recently i took my GN to a local dyno to get some base line runs. I made two runs on 93 octane ,which i think was a big mistake.I should of been on the safe side and run race gas. Well anyways i thought for sure the engine could easily run up to 6500 rpms.Power peaked at 5700 rpms than it Maybe missed or pinged causing dips in the hp curve(see above pics).Fuel pressure never dropped and peaked at 60 psi with boost.

1.So my question is what could cause this dip ,detonation, could it be tune, octane,plugs?????
2. Could the turbo cause this car to peak alot earlier than i expected (5700rpms instead of 6500)???surely there is more power to be gained at higher rpms, or no??
3. If i raise boost will it peak even earlier???
4. Dyno operator said AF was alot higher than he would feel safe with at 93 octane, whats your take??

Orginally i thought the turbos were 60-1 ,i was told the turbos look alot bigger than 60-1.here`s a pic of the engine bay

Engine bay pics

You need to fatten up the AF and what is your WOT timing???

 

[daverr]

You need to fatten up the AF and what is your WOT timing???

we were going to do that by increasing the fuel pressure but called it quits.I dont know what The WOT timing is set at.

 

[DCVING 6]

I see you are in Chicago. Our Chicagoland Buick Club is having a dyno day in Joliet on the 14th. I'm sure there will be some people there than can give you a hand. www.chicagolandbuick.org

Dyno Session with Meeting
Saturday; October 14, 2006; @ 8:00 am
ATR Motorsports
550 N. Chicago St.
Joliet, IL 60432
Al's number: 815-726-7866

 

[daverr]

Joliet is pretty far from me unless i trailer the car.

 

[HighPSI]

we were going to do that by increasing the fuel pressure but called it quits.I dont know what The WOT timing is set at.

What are you using for engine managment?

 

[daverr]

What are you using for engine managment?

Motec

 

[XXQUICK6XX]

Dyno Day

Bring it down but put some c-16 vp fuel in it. Be nice to see it. Pry have mine and my sons car there.

Steve

http://www.chicagolandbuick.org/pdf/october/technical_session.pdf

 

[John Wilde]

Talk to Shane T, he can help you with tune.

http://www.fastmotorsports.com/consulting/eficonsulting.htm

 

[daverr]

Talk to Shane T, he can help you with tune.

http://www.fastmotorsports.com/consulting/eficonsulting.htm

So u think it might be in the tune??
I`ll talk to Shane to see what his take on it.
also do u think my peak power rpm is kinda low?? i thought for sure with the cam this car has it should go to 6500 rpms.Maybe the back pressure is building up??

 

[John Wilde]

So u think it might be in the tune??
I`ll talk to Shane to see what his take on it.
also do u think my peak power rpm is kinda low?? i thought for sure with the cam this car has it should go to 6500 rpms.Maybe the back pressure is building up??

Since we have no idea what the timing is and the AF is to lean I think the tune is a great place to start. If you just put in c16 in it and try it again that could give you a good idea. I would leave the timing low in the 16-18* range so that you will not have to worry when you nail it. Since you have a Motec please don't tune with the fuel pressure regulator. You can how ever turn it up 10psi and see
if it helps the issue. This is more a trouble shooting tool and not a fix.
For AF ratio at WOT on pump I would look for something in the mid to lower 11s.

Please let me know how things go!!!

 

[daverr]

I have a spare old computer not a laptop, im going to use to see what the timing is set at. This motec (old motec 95-96) uses a serial connection, todays laptop do not have serial ports.

 

[daverr]

Ok i hooked up the pc to the car . I have an error message for the Ambient temperature sensor. Also the rev limiter is set for 7600 Rpms. Looks like at 15 psi the ign timing is set for 24* check out the pic(sorry pic is a bit blurry) . If your familiar with motec and want to see something else let me know.Looks like im going to have to put C16 in it and try it again.

Ignition table

 

[John Wilde]

Ok i hooked up the pc to the car . I have an error message for the Ambient temperature sensor. Also the rev limiter is set for 7600 Rpms. Looks like at 15 psi the ign timing is set for 24* check out the pic(sorry pic is a bit blurry) . If your familiar with motec and want to see something else let me know.Looks like im going to have to put C16 in it and try it again.

Ignition table

Dave drop the timing map to about 18* at 15psi and that should do the trick.
I would not run that kind of timing (24*) with out at least 110 octane.

 

[daverr]

Dave drop the timing map to about 18* at 15psi and that should do the trick.
I would not run that kind of timing (24*) with out at least 110 octane.

I would have to drop timing all around right not just 15 psi but below too right? I need to try one thing at a time, so next time i go to the dyno i`ll put c16 in it and see if it does anything.

 

[daverr]

I took out a sparkplug , it`s a Autolite AR3924 Racing. Is this plug in the right heat range??

 

[daverr]

I took my car to the Buick club dyno meet. This time i put C16 in it and a set of colder plugs. The car is doing the same thing (backfiring). This time i was in the driver`s seat so i could see whats going on. Here whats happening.The boost would go up to 16 psi and drop (3-5 psi) after about 6000 rpm.Then it would start backfiring from the exhaust. Raising the boost did the same thing.Also raising fuel pressure did not help either.

I couldnt find a vacuum leak on the car , it idles 7-9" vacuum. My passenger side header has a small leak.I should of open the exhaust cutout to see if it would of helped any.

 

[BlownV6]

I dont claim to know anything about EFI management !! but a question that comes to my mind , is the motec you have set up for a v6 ?? if it is set up for a v8 the rev limiter set at 7600 for a v8 would be 5700 on your v6. dropping cylinders puts raw fuel in the exh which will ignite creating a backfire. also what plug gap are you using? to much gap can cause a misfire at high rpm or cylinder pressure.... just some thoughts mike

 

[daverr]

interesting i never thought of that. I`ll hook my computer to the car and change the rev limiter setting or turn it off.See if that changes anything. i also have a MSD box on it i think it`s a 7 al (gold color box).

 

[BlownV6]

If the 7al box is not set up for a v6 then the rev limit chip will hold the engine at 75% of its rate. remember a rev limiter counts ignition pulses, a v8 has 4 per rev , a v6 has 3. Now that I think about that--my previous statement was wrong!! if your rev system is set up for a v8 and you have the limit set at 7600 then it would actually be at 10200. sorry to get you off track on that , Ill be quiet now . good luck mike