MY DYNO EXPERIENCE WAS VERY USEFUL

Tom Kelly

Active Member
Well, after feeling everything is done on the 86 GN before it goes into paint this winter I took it down to DeCordre Automotive in Spring City PA so Brandon DeCordre could finish things up before racing begins next Spring. This past April, my son and I took it to Lebanon Valley to “check things out” while it was still on street tires. We did several ¼ mile passes there getting as expected terrible 60 foot times on the street tires (around 2.5-2.6) but nevertheless turned in times of around 13.6-13.7 at around 103-104 mph. Not bad for an exploratory day. However the turbo inexplicably jumped up past 27-28 pounds of boost and the head gasket let go in the final run. We were able to drive it home although we used five quarts of oil to get there. That led to the removal of the engine and complete rebuild using comp cams roller cam, forged pistons, new valve springs, etc. as well as a rebuild of the turbo which had bad bearings and seals after the adventure in Lebanon Valley. Thanks to John Csordas and all the gang at the Auto Center in Chappaqua, N.Y.

And so now we went on to the DYNO to see how to get the most out of this wonderful car. I learned so much on this trip:

1. First the final results so you don’t have to remain in suspense. Best run on the Mustang DYNO yielded 337.8 hp and 388.0 lb ft of torque (both at 4,579 rpm) at the rear wheels. This translates roughly to about 397 hp and 456 lb ft of torque at the crank (assuming 15% loss through the drive train. Much more than I expected.

2. Using the air fuel sensor Brandon installed we were able to increase power by flattening out a richness using the turbo tweak adjustment procedure.

3. We were nly able to go to 21 lbs of boost (at #7 on my alky controller) because after tha the installed boost controller let go and boost would go uunabated (Now we know what happened at Lebanon) Brandon recommended I install a Walman controller for more precise control. He expects that the car would be happy up to around 25-26. I would probably limit it to 23.

4. At the end of the day we opened up the exhaust (car has the qtip electric cutout) to see if that helped or hurt. We’ll never know because the knock sensor would interpret the noise as knock and it retarded the timing 5-6 degrees cutting power. Solution is to leave them closed or remove knock sensor. I’ll leave the cutouts closed except at cruise nights LOL.

5. During the process Brandon noted small amounts of oil smoke at idle and part throttle and by looking at the plugs suggested we might still have a partially leaking seal in the turbo as no oil was going through the engine. We’ll check that out.

6. Speaking of plugs he pointed out that colder plugs (NGK #6) would reduce chance of detonation. Good tip.

7. We identified a mysterious lean spot in the early part of each run. It lasted for almost exactly one second. Eric at turbo tweak will discuss this with Brandon when the two of them connect but Eric suggested it’s a common showing on DYNO’s that may not apply to real life runs. We’ll see.

8. Discovered for sure that my lockup converter isn’t locking up. On the dyno at 2050 rpm’s it dropped to 1800 when he jumped the wires. Looks like just a loose wire/bad connection somewhere under the dash. Should be fixable.

9. Brandon demonstrated that if I want best performance in the ¼ mile I should do the runs in Drive and not overdrive. I hadn’t been sure of which is better until he showed me. Also he showed me how ¼ mile times ( though not fuel economy) would improve with 3.72 gears. He showed me that with the 3.41’s I would have to reach 126 mph to get to 5,600 rpm’s. His opinion is that the car would be good up to around 6,000 if I wanted to push it that hard.

So all in all a wonderful day and so educational. I recommend it to all who can’t do it for themselves. I am thinking of all the testing and tuning this one day saved. Total cost $750. Well worth it.

IMG_2298.JPG
 

flbuick

Active Member
Yes, the dyno is an eye opener. I had similar results at 18# boost, 341hp and 373tq. I'm running a little bigger turbo but you have the roller cam... We tested mine at KDK in Orlando and I kept it conservative on the boost because as you noted, a blown head gasket is a slippery slope.
 

hensleyt

Well-Known Member
Its not a HONDA so leave the 3.42 gears in her
Max HP and torque was at 4500, no need to go over that. Maybe 5200 ,but why?
Is this with stock heads? And a 206 cam?
It might be real retard with the cutout open,I can see it going lean.
 

Buick Mark

Active Member
I concur, leave the 3.42 gears in it, it loads the engine, thus the turbo spools quicker.
Its like trying to build boost in park:arghh:
 

Pronto

Believe nothing you hear and half of what you see.
Good till 6k, hahaha. So many things wrong here it's entertaining.
 

Mr.Spool

Well-Known Member
Well, after feeling everything is done on the 86 GN before it goes into paint this winter I took it down to DeCordre Automotive in Spring City PA so Brandon DeCordre could finish things up before racing begins next Spring. This past April, my son and I took it to Lebanon Valley to “check things out” while it was still on street tires. We did several ¼ mile passes there getting as expected terrible 60 foot times on the street tires (around 2.5-2.6) but nevertheless turned in times of around 13.6-13.7 at around 103-104 mph. Not bad for an exploratory day. However the turbo inexplicably jumped up past 27-28 pounds of boost and the head gasket let go in the final run. We were able to drive it home although we used five quarts of oil to get there. That led to the removal of the engine and complete rebuild using comp cams roller cam, forged pistons, new valve springs, etc. as well as a rebuild of the turbo which had bad bearings and seals after the adventure in Lebanon Valley. Thanks to John Csordas and all the gang at the Auto Center in Chappaqua, N.Y.

And so now we went on to the DYNO to see how to get the most out of this wonderful car. I learned so much on this trip:

1. First the final results so you don’t have to remain in suspense. Best run on the Mustang DYNO yielded 337.8 hp and 388.0 lb ft of torque (both at 4,579 rpm) at the rear wheels. This translates roughly to about 397 hp and 456 lb ft of torque at the crank (assuming 15% loss through the drive train. Much more than I expected.

2. Using the air fuel sensor Brandon installed we were able to increase power by flattening out a richness using the turbo tweak adjustment procedure.

3. We were nly able to go to 21 lbs of boost (at #7 on my alky controller) because after tha the installed boost controller let go and boost would go uunabated (Now we know what happened at Lebanon) Brandon recommended I install a Walman controller for more precise control. He expects that the car would be happy up to around 25-26. I would probably limit it to 23.

4. At the end of the day we opened up the exhaust (car has the qtip electric cutout) to see if that helped or hurt. We’ll never know because the knock sensor would interpret the noise as knock and it retarded the timing 5-6 degrees cutting power. Solution is to leave them closed or remove knock sensor. I’ll leave the cutouts closed except at cruise nights LOL.

5. During the process Brandon noted small amounts of oil smoke at idle and part throttle and by looking at the plugs suggested we might still have a partially leaking seal in the turbo as no oil was going through the engine. We’ll check that out.

6. Speaking of plugs he pointed out that colder plugs (NGK #6) would reduce chance of detonation. Good tip.

7. We identified a mysterious lean spot in the early part of each run. It lasted for almost exactly one second. Eric at turbo tweak will discuss this with Brandon when the two of them connect but Eric suggested it’s a common showing on DYNO’s that may not apply to real life runs. We’ll see.

8. Discovered for sure that my lockup converter isn’t locking up. On the dyno at 2050 rpm’s it dropped to 1800 when he jumped the wires. Looks like just a loose wire/bad connection somewhere under the dash. Should be fixable.

9. Brandon demonstrated that if I want best performance in the ¼ mile I should do the runs in Drive and not overdrive. I hadn’t been sure of which is better until he showed me. Also he showed me how ¼ mile times ( though not fuel economy) would improve with 3.72 gears. He showed me that with the 3.41’s I would have to reach 126 mph to get to 5,600 rpm’s. His opinion is that the car would be good up to around 6,000 if I wanted to push it that hard.

So all in all a wonderful day and so educational. I recommend it to all who can’t do it for themselves. I am thinking of all the testing and tuning this one day saved. Total cost $750. Well worth it.

View attachment 313365
Boost doesn't break the motors.having not enough fuel, too much timing,not enough octane does.I have run 30psi on a stock turbo and a 49turbo.i would suggest a perfect goal with a shift rpm below 6000 with your mild combo that 49 on a heads cam no comp motor will still run out of breath before you ever reach that rpm.
 

Tom Kelly

Active Member
Its not a HONDA so leave the 3.42 gears in her
Max HP and torque was at 4500, no need to go over that. Maybe 5200 ,but why?
Is this with stock heads? And a 206 cam?
It might be real retard with the cutout open,I can see it going lean.
Maybe but the a/f sensor did not show lean. The only change in the run was the retard and resulting power los. This is why he suspected the knock was false.
 

Tom Kelly

Active Member
Maybe but the a/f sensor did not show lean. The only change in the run was the retard and resulting power los. This is why he suspected the knock was false.
I think his point was that I should leave it in drive as opposed to overdrive and not be afraid of overrevving. He didn't suggest going to 5,600 or 6,000 but was trying to reassure me that the engine could handle going well over 5,000. As to the steeper gears he was saying that they could enable quicker launches if the driver (my son) could learn to handle them. His calculation of rpm's with the steeper gears was again just meant to tell me that the car would not overrev with them.
 

SCOOBY DOO

I'M NOT A MONSTER, I'M JUST AHEAD OF THE CURVE!!!
Leave the 3.42's in it. Get yourself Powerlogger...so you can verify exactly what's going on. Guessing is never a good idea.
 

Pronto

Believe nothing you hear and half of what you see.
I know guys running 10s that aren't revving to 6000 rpm. No mention of head work. No reason even with no head porting, you should have to rev more than 5200. 3.42s with a 28" tire will put you right there. With some real boost put to the 49 you should easily be able to run a 11.5. Tires, tune and seat time. Going to colder plugs is common knowledge here. A wideband and powerlogger are your friend. You could have bought those for $750.
 
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