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Discussion Starter #1
Just came back from the dyno shop to get a baseline reading on my new gran sport before I start the mods. It showed peak hp at 308hp @6000 then a flat curve until 7500 with some dips in the numbers on the way. I was expecting to see 330-335 at the wheel. Torque was @279 ft-lbs @ 5000 rpm. The car started running really rich at about 5500 rpm. Could that be the problem, I thought these engines peaked output at 7000 rpm.

- one confused gransport owner, ps I still love the car
 

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Sounds like something was not configured right. I've never seen a completely flat HP curve or even torque unless it was being controlled by a computer wastegate on a turbo car. Maybe the ECU was protecting the motor because it wasn't moving and retarding spark. That's my guess.
 

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Definitely something amiss. My 2002 CC showed about 335RWHP on a Dynojet dyno - I thought the GranSports were rated at 10 HP more.

Some questions:
1. What brand of dyno equipment?
2. Did the operator use a fan to keep air moving through the radiator?
3. If two-wheel dyno, was Traction Control turned off?
........That's given me some problems in past dyno runs
........Best to start the car, turn off Traction Control, then shift into gear
4. Does your GS feel sluggish in mid-range, reflecting accurate dyno results?

The fuel ratio sounds like the key - see my dyno results (bone stock, original ECU software), below. The ratio steadily declines; just what you would expect.

 

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What type of Dyno was used? Most guys dyno'ing 330-335 are using a Dynojet. Dyno Dynamics or Mustang Dyno will read lower.
 

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Discussion Starter #6
used a dyno jet, traction control was turned off, the problem is definitely from 6000 rpm and above. Don't know, I am dropping off the car at my dealership to run a diagnostic, and if it doesn't improve, they better fix it, because I dodn't pay that price for 300 rwhp.Maybe the fan wasn't big enough to create the needed air flow for the enigne at that speed.
 

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gransport13 said:
used a dyno jet, traction control was turned off, the problem is definitely from 6000 rpm and above. Don't know, I am dropping off the car at my dealership to run a diagnostic, and if it doesn't improve, they better fix it, because I dodn't pay that price for 300 rwhp.Maybe the fan wasn't big enough to create the needed air flow for the enigne at that speed.
May not be the car, may be the dyno, may be the setup of the fan. You should see the dynos of companies like RUF, makes what we use in the states look like a joke.


If I were in your position, I would do the following; if it is reasonable and your car feels fine to you, I would find another GS or at the least a Coupe/Spyder owner to run next to you. If their really is a 30rwhp difference, it will show.
 

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Discussion Starter #8
Finally went to a dyno with proper setup. Big fan capable of 100mph winds and more. The car did 348.6 hp and 312.4 ft-lbs. I am a little happier, but I can know start to get this car over the 400hp mark at the wheels. I will keep everybody informed as i make my progess. I am having a company do a mock supercharger system for me. But that won't be ready for another 6 months or so. I am just going to do ecu tuning and open up the exhaust a little bit.
 

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gransport13 said:
Finally went to a dyno with proper setup. Big fan capable of 100mph winds and more. The car did 348.6 hp and 312.4 ft-lbs. I am a little happier, but I can know start to get this car over the 400hp mark at the wheels. I will keep everybody informed as i make my progess. I am having a company do a mock supercharger system for me. But that won't be ready for another 6 months or so. I am just going to do ecu tuning and open up the exhaust a little bit.
Modena-Tec broke over 550 at the wheels with a supercharger. With the right clutch on stock internals this car is fine for 700hp and possibly even further.
 

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Hey Gransport13
Glad you got the dyno situation figured out. Those #s sound more like it.

I may be missing something here, but what is a "mock" supercharger? Do you mean they are going to see if it is feasible to build one? Are you talking to VF engineering? The have full cad capabilities and plastic moulding machines for one off construction. I would be interested if you are going to move foward with it. I am sure to bring down the cost if you have someone making one, we could have a few made and get some interest from this site.
let me know how it goes. I am investigating some porting and polishing now, but a blower would be even better.

Keep us posted
Robb
 
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