Massive Power Loss Whipple Gt

[gtkurt]

Today in sunny Arizona I experienced a massive power loss in my GT. It has been around 100 degrees here today. I was racing around with a friend with a modded GT2 and after some hard driving it was total obvious something was wrong. When I floored it it was almost like the car was bogging or the clutch or the supercharger belt were slipping. Does any one know what was happening? Does the GT's computer pull timing when it senses hot air?

My GT has the following mods.
Whipple with 23lb pulley all though I only make 21lb (no exhaust restriction)
Accufab Throttle Body
Stainless Works Headers No cats No muffler
Spec clutch
Trans axle cooler
Twin Kenne Bell boost a pumps
109 unleaded fuel
SCT custom tune
Kitchen sink:lol

I would appreciate any help. This is a very embarrassing situation.
Thanks Kurt

 

[BlackICE]

I am not an expert by any means, but if it was running fine for some time then the engine got hot (lets say 220-240 F) range and the power was way down. It could be the tune yanking out a lot of timing due to the heat. If the power came back after the car when cooled down this is probably it. Ask the person that tuned the car at what temperature does the timing get dialed back and to what extent.

100 in AZ is hot!

You may get better overall performance at a lower boost with the same high octane gas. That would allow the tuner to leave more timing in due to the safety factor of the lower boost with 108. Maybe go two size down to the 19 psi pulley. If will still leave a GT2 behind if the timing doesn't get reduced.

 

[everetto]

Did it return to "normal" later? Or have you driven it again since?

 

[barondw]

Kurt

Do you still have the stock muffler? What you describe sounds a lot like heat sink. Meaning that the engine or certain components absorb heat and the heat causes a loss of power. Very, very common with stock vehicles ont he street and track.

Even if the stock muffler has been removed if there is not sufficient air flow through the engine comparment heat soak will be created. You must have nothing in front of the exit grill at the rear of the engine compartment and the "improvements" must not add additional heat.

A before session and after session pyrometer would tell a more complete story. Would take readings of the blower, headers, exhaust, and engine block.

Dave

 

[californiacuda]

Don't get bummed out, just takes some time to get all the bugs worked out. Sounds like a great ride, enjoy the whole experience.

 

[BlackICE]

The 2 parameters that matter most for the ecm to back off the timing is the IAT (inlet air temp) and coolant temp. Both these number can be monitored while driving by devices that connect to the OBDII port on the car. Tuning devices such as the Predator and SCT Xcalibrator 2 can do this. Other temps don't matter directly, but may contribute to raising the other numbers that matter.

 

[gtkurt]

The coolant temp was only 200 to 205 the car never was any where close to the red.(240)
The power does come back when it it cools down. Such as driving at normal speeds or letting it sit.
I have no muffler or cats I would think that would help.

And if all of that was not bad enough my factory Ford trans axle cooler line blew. It must have happened just before I got home. There is a blood trail going through my neighborhood and a giant pool on my garage floor. I was lucky it did not get to my headers. I lost a Viper to fire already.

 

[BlackICE]

It is good that the car runs fine after it is cooled down. I think the air temperature post supercharger compression is causing your problem. At 21/23 psi boost the supercharger heats the air quite a bit. This is not a problem when the intercooler's coolant is relatively cold. After driving for a while the intercooler's coolant temps rise and can no longer cool the air enough, so to prevent detonation the car's ecu backs off the timing and you lose power.

To verify this condition, check the intercooler's coolant using an IR meter on the coolants tank. Check the temp under easy driving conditions and then after you have lost power.

If confirmed you can live with is or,

1. Run lower boost to reduce the temp rise.
2. Add an additional heat exchanger for the intercooler's coolant.
3. Add more intercooler coolant capacity. This will long forestall the problem. Double the capacity and you will go about twice as far before losing power.

Another though, at what temps does your radiator fans turn on? If it was not modified and you were below 220f then only the cars motion through the air was cooling the heat exhanger. This won't be an issue at 80mph or more. The car's motion is such that the fans don't matter much. Also turn off the A/C since its heat exhanger is in front of the intercoolers, thus pre-heats the air that is suppose to cool the intercooler's coolant.

Good luck and you have an awesome setup, but is seems that without beefing up the intercooler system the 23 psi pulley is not good for extended high power use.

 

[Fubar]

If it got really hot, the computer will shut things down. It will feel like your towing a boat.

I did that last year with mine. It was 110 here and I was drafting the instructor on a track. All of the sudden I had no power and the temp needle was int he red. As sson as it cooled down everything was fine.

 

[californiacuda]

How about a secondary coolant tank plumbed into the ic system that can be filled with ice water?

 

[gtkurt]

How about a secondary coolant tank plumbed into the ic system that can be filled with ice water?

californiacuda what are you going to use for ic on your turbo set up. have you got to start it up yet? I keep thinking about turbos as well. Soon there might be a slightly used Whipple on the market.

Thanks every one for there thoughts on my problem.:thumbsup

 

[BlackICE]

How about a secondary coolant tank plumbed into the ic system that can be filled with ice water?

From the heat neccessary for a phase change from ice to liquid and then heating water from 0C to 100C you need about 0.71 btu/grams. According to the SAE papers on the GT the intercooler needs to dump 2100 btu/min at 200 mph.

That means with the stock motor you need about 3kg of ice per minute of running time. After that it is not going to help you. Ice/water is about 8 pounds or 3.6 kg per gallon. So each gallon of ice will buy you one minute of maximum output. This assumes that you don't have the heat exchanger, but gives you some indication of the amount of heat that is generated.


http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase.html

 

[Fubar]

From the heat neccessary for a phase change from ice to liquid and then heating water from 0C to 100C you need about 0.71 btu/grams. According to the SAE papers on the GT the intercooler needs to dump 2100 btu/min at 200 mph.

That means with the stock motor you need about 3kg of ice per minute of running time. After that it is not going to help you. Ice/water is about 8 pounds or 3.6 kg per gallon. So each gallon of ice will buy you one minute of maximum output. This assumes that you don't have the heat exchanger, but gives you some indication of the amount of heat that is generated.


http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase.html

I don't know about you guys but when I hear this kinda stuff... I just get a blank look on my face and say "whats it gona cost?"

 

[californiacuda]

Wow, thanks for the analysis. Might still be a good idea for 1/4 mile, or 1 mile runs.

So, I guess some solutions to the problem might be, change ic coolant to water only, additional heat exchanger, lower boost(less heat), fluid inter cooling-either nitrous or water/alcohol, cooler running fuel-e85, fan in the engine compartment, etc.

Out of all of the ideas, I like water injection the most. Usually used for detonation suppression, but in this case its primary purpose would be, to cool the charge air. Water has a very high specific heat and would draw mucho heat out of the charge air and engine. No need to use alcohol and be concerned about it's reaction with aluminum. There are many kits available that read boost and only begin to spray at a certain boost pressure. Could also be temperature and boost activated. What do you think?

 

[BlackICE]

Water injection in theory is a good idea, but some things to think about.

Even without alcohol I have concerns about aluiminium corrosion.

The best place to inject the water would be in the 8 intake tracks of the cylinders, but that would be major surgery. The only easy place would be the intake of the supercharger.

As with anything adding more things in the path of must work increase failure rates if something goes wrong. You most have a sensor and controller that limits boost and or timing if the water runs out. Limiting boost to some extent can be easily done with the supercharger bypass solinoid.

CA cuda what are you using on your GT? I thought is was a Whipple, but someone mentioned a TT.

I think for the mile, pre-cooling the IC coolant to below 0C and adding a ice cooler inline would work great provided you have a tune that takes into account the colder IAT.

 

[californiacuda]

With all the stuff that TRBOKLR has on his car, a simple water injection system is not very complicated. My car is a TT and I'm about to get the engine back. So far, the intercooling is stock.

 

[BlackICE]

With all the stuff that TRBOKLR has on his car, a simple water injection system is not very complicated. My car is a TT and I'm about to get the engine back. So far, the intercooling is stock.

From others post the TT setup has less of a heat soak problem. If I ever get the Racelogic traction control worked out, its launch control would be real useful for a TT.

Do you have the Heffners or Stage 6 TT systems, or another?

 

[californiacuda]

Accufab built it, and I am definitely interested in Racelogic

 

[04mach1]

I think meth injection would help you.

 

[californiacuda]

There have been some posts in the Cobra Lightning forums about water/meth injection. Their results haven't been what they were looking for. They wanted more hp using low octane fuel.

With the supercharger closed system, the oxygen amount per volume of air could not be increased as the temperatures were decreased. I still think it would be very successful at dropping temps, which is the main issue being discussed here.