Added Boost & Lost Power... Help!

[Daryl B]

I month or so back I decided to install a larger radiator to help with my engine cooling problems. I figured, since I was going to have the radiator out of the engine compartment it might be a good time to do the lower pulley. Anyway, I put on the 6lb lower and chnged my top to a 4lb. Went to the dyno and A/F was way off and power down. I expected this might happen so I borrowed a chip from a buddy who is running the same set up. The A/F was much improved but the power was still down (with 4 lbs more boost). I decided to run with a 2lb upper and a 6lb lower and figured I would have my chip burned for that setup. Today I got the Predator in and couldn't wait to try it, so I took my car to the Dyno.

I will attach 2 dyno sheets. The first is my dyno with the Predator (Run 31) base pullied program and (run 24) my last pull before the lower pulley install. Max power is down 33 and torque stayed about the same (with 2lbs more boost). The A/F reading is from a bung located just before the passanger side Cat. Some might say I lost power because the car is running richer....but look at the next dyno. This dyno was with some adjustments from the predator to lean it out. I tried a bunch of diferent combos and the A/f was anywhere between 11.2 & 11.8 but power never improved.

There are 2 guys running uppers and lowers that I am friends with. They both saw a significant increase in Tourqe and neither of them went backwards in power. Any ideas on what is going wrong?????

Thanks in advance for your help.

 

[Daryl B]

2nd Dyno

 

[Shadowgray03]

There is more to power than just A/F, timing also plays a big role and if you add a lot of boost air charge is hotter and EEC can pull timing.

 

[Daryl B]

I did play with the timing on the Predator and tried several things but I could see how that might not work. But I am baffled how I can use the chip out of a car with the exact same mods, get the same A/F and make considerably less power than they did?

 

[03Sssnake]

Hmm..You say you advanced timing, by how much? They AF looks alittle lean early on, but fattens up on the big end. So you may be too dry down low. You might wanna get it tuned for more fuel down low. Was there any evidence of belt slip? That or you may have a slipping clutch, any catpiss smell on the runs :shrug: My dyno runs were real inconsistent @ the same dyno. The operator thought the clutch was slipping. On back to back runs, the car was down 20 hp 20 tq, then in the next run it was backup. I have since replaced the factory clutch with a RAM clutch, but have yet to go back to test.

 

[94SVT Coupe]

Clogged cats?

 

[Daryl B]

No belt slip. The cats are fine. I didn't smell anything unusal.

 

[carstocks]

I'm guessing clogged cats as well.

 

[UltimateSVT]

Check your spark plug gap. I run mine at .034" and that seems to work great. It looks like you have a lot of spark blow-out in the upper RPMs.

 

[sambandit]

Yeah, mine are at .035. Can't imagine that would be worth 30 hp but I'm running outta ideas. Maybe close that gap a little while your contimplating a 12 second pass tonite!

 

[venomousSonic03]

Sambandit really has no clue what he is saying Daryl and we all know that!!!

 

[sambandit]

I got your clue in my pants. Bend over and I'll show it to ya!

 

[94SVT Coupe]

Could be your belt too. Tim had a Gatorback cost him around 40-50 RWHP. The "teeth" ends were starting to roll up. A new belt fixed it. He thought it was the plugs or sprak blowout at first too. Ther weren't really any obvious signs of slippage either.

 

[KiLLaBytE]

if you changed out both pulles, 4lb lower and added 4lb w/ the upper, that means you're running at least 16lbs on the eaton. If i recall correctly, the eaton is only efficient up to about 14,000 RPMs, which is around 12-13psi. Overspinning the eaton could be causing the air to be too hot, and heat-soaking the intercooler causing you to actually lose performace. i'd say try replacing one of the pullies with stock (upper would be easier) and see what happens. I left the lower stock, and added a 2.93 upper. Had it dynotuned by Willie @ Diablosport and put 452 to the wheels on my 4th dyno pull on a Mustang Dyno (#s are higher on a Dynojet).

If it's not belt slip, and you're 100% sure it's not, it's most likely the above. The best way to check for belt slip is take a bottle of white-out, and draw a line starting on the top edge of the upper pulley onto the belt. Run the car for a bit, give it some throttle. If the line is no longer lined up, it's slipping.

Hope this helps!

 

[Fang]

Daryl, how did the radiator swap go? Did you at least see some results on that? Hope the install was smooth. Sucks to be loosing power though.

 

[onerichrunner]

You shouldn't have had a power drop and there should have been a power increase from 11.2 to 11.8. Try putting it at 12.00 Nothing bad will happen and were you able to log timing? If so where was it?

 

[Daryl B]

"UltimateSVT Check your spark plug gap. I run mine at .034" and that seems to work great. It looks like you have a lot of spark blow-out in the upper RPMs. "

----I will check my gap. I have some new plugs to put in anyways.

Originally posted by 94SVT Coupe
Could be your belt too. Tim had a Gatorback cost him around 40-50 RWHP. The "teeth" ends were starting to roll up. A new belt fixed it. He thought it was the plugs or sprak blowout at first too. Ther weren't really any obvious signs of slippage either.

-----The belt is brand new. One of the pullies I tried was a new anti-slip and even lost power with it.

"KiLLaBytE if you changed out both pulles, 4lb lower and added 4lb w/ the upper, that means you're running at least 16lbs on the eaton. If i recall correctly, the eaton is only efficient up to about 14,000 RPMs, which is around 12-13psi. Overspinning the eaton could be causing the air to be too hot, and heat-soaking the intercooler causing you to actually lose performace. i'd say try replacing one of the pullies with stock (upper would be easier) and see what happens. I left the lower stock, and added a 2.93 upper. Had it dynotuned by Willie @ Diablosport and put 452 to the wheels on my 4th dyno pull on a Mustang Dyno (#s are higher on a Dynojet).

If it's not belt slip, and you're 100% sure it's not, it's most likely the above. The best way to check for belt slip is take a bottle of white-out, and draw a line starting on the top edge of the upper pulley onto the belt. Run the car for a bit, give it some throttle. If the line is no longer lined up, it's slipping.

Hope this helps! "

----I agree there is a point of dimishing returns with the Eaton but 2 03 Cobras have done this here sucessfully. I had the highest HP/TQ out of eveyone without a lower so I thought I would put down higher numbers than the other when I did the lower as well. I could have some slippage but my boost is not falling off like it was before the lower. I am definately getting more boost or my old tune wouldn't be screwed.

 

[Daryl B]

Originally posted by Fang
Daryl, how did the radiator swap go? Did you at least see some results on that? Hope the install was smooth. Sucks to be loosing power though.

Dan,

The install was much easier than I thought it would be. I did not have to drill, bend brakes lines, or relocate anything. I still need to find some foam to put between the radiator and the front. If you decide to do yours, let me know and I would be happy to help. As for the temp, I honestly do not know because the hot days are gone. What is the story with your car?

 

[Daryl B]

Originally posted by onerichrunner
You shouldn't have had a power drop and there should have been a power increase from 11.2 to 11.8. Try putting it at 12.00 Nothing bad will happen and were you able to log timing? If so where was it?

It was my first time with the Predator, so I was trying to log the timing but I don't think I got it to work. I adjusted the A/F as lean as I could get it. I might need to have Diablo send me a custom tune but, like I said earlier, I tried a chip with the right custom tune on it.

 

[onerichrunner]

Originally posted by Daryl B
It was my first time with the Predator, so I was trying to log the timing but I don't think I got it to work. I adjusted the A/F as lean as I could get it. I might need to have Diablo send me a custom tune but, like I said earlier, I tried a chip with the right custom tune on it.

If you can't get anywhere where you bought it from let me know and I will load something in there that will run like a scalded cat AND be safe.

Good luck!

Shawn