Interesting trip to the Dyno today

[randall]

Redgts,

" WORSE THAN A CREAMPUFF"

you have a creampuff

BTW my creampuff ran 430 rwhp/477tq
creampuff means you have a smoother engine that produces more low end torque do to the state-of-the-art lighter weight pistons and re-configured cam profile

 

[RedGTS]

Believe it or not, I actually have Ron Hickey's old Snake Oyl exhaust, so maybe that's what it is.

 

[ronviper]

Try the Sean Roe air fuel computer, it gives approx 20-25% fuel + or - . It also will give or take away timing depending on the settings. I love mine when the car seems slow i play with the settings depending on the wheather. My car seems to respond very well to this little controller.

 

[Jerry Dobson]

RedGTS, How did you get a Air/Fuel ratio? Normally you want to read it in front of the CATS. Do you have CATS installed? A O2 tube up the rear will give missleading ratings. Most of the headers will have an O2 **** to screw into but you did not list headers.

Your HP is not too far off. It will actually continue to increase up to 15k miles.

Are your air filters dirty or do they have too much filter oil on them?

Viperzzilla, Your saying 495HP with Filters/Tubes/CatBack ???? I would be impressed. Not saying impossible....but pretty close to it.

 

[RedGTS]

The A/F ratio was taken from the tailpipes, and yes, I do have factory cats. Obviously I don't know if the readings were accurate or not. My filters are Roe/SB's that I just put in maybe a month or two ago so I would think they're fine. It could well be that the readings were off, but the readings were leaner on the two later runs that made more power.

 

[RedGTS]

Well I finally took my '01 GTS to the dyno today to see what she has. Some of you may remember my "non-tireburning" post asking whether my failure to burn rubber from a roll was normal (the responses were mixed), so I was looking forward to getting some feedback on the power level. By way of background, my car has 7,700 miles, tubes, filters, and Snake Oyl rear muffler delete.

We had the engine running on the dyno for several minutes trying to get everything hooked up right, and I was somewhat concerned about heat soak. In any event, the first pull was very disappointing--378 rwhp and 414 rwtq. Worse than a creampuff, but the air/fuel ratio was off the charts rich at less than 10:1.

For the second run, we wondered whether the lack of air was the major problem and decided to direct a leaf blower toward the NACA duct from ~4 feet away. After waiting 5-10 minutes for cool down, we ran it again and out popped 414 rwhp and 448 rwtq! A bystander told me a puff of black smoke came out when I floored it. Air/fuel was around 11:1, and the run went by noticeably quicker.

After waiting another 5-10 minutes, we did a third run with no leaf blower and got 415 rwhp and 459 rwtq! Air/fuel was about the same ~11 or 11.5:1. This was a big relief, because while a permanent electric leaf blower mod might have been relatively inexpensive (even with twin blowers

), it wouldn't have added a lot to the Viper's mystique.

My layman's conclusion: It's the computer, stupid! I don't think it was ready for the first run because all my putt-putting around town with very few short blasts at WOT had not prepared it for an extended dyno run. It did learn quickly and well, however! In short, these beasts need to be blown out regularly to keep the computer from bogging everything down.

All in all, I left a happy camper and feel I have a good baseline to mod from. Any thoughts and comments are welcome, of course.

Ronnie

 

[ruckdr]

Ronnie,
Sounds Rich to me, at 11.5 air/fuel. Mine a gen1, ran very flat during the entire runs at 13.5 - 14.5 air/fuel. Understand the cams are significantly different, and thus the engine demands, but still sounds quite rich.
Later,

 

[RedGTS]

What would cause it to run too rich? Do I need to go get a tuneup?

After the last two runs, I figured I had all the power I could hope for with the limited mods I have and that the tune must be pretty good. But if there is more there to be had, I'm all for that.

 

[toddt]

Your experience is not strange. If the computer hadn't learned yet, your car can and will run extreemly weird.

When I bought my viper, the battery had been dead. We jumped it, and got on the road.

It would not even IDLE. I had to keep my foot on the accelerator just to drive!

Well, I called it a ******, and lowballed the offer. He took it, and to make a long story short, in one week the car was running as silky as a three-day-old kitten! Didn't have to do a thing to it!


Another thing--BAD GAS will ruin your day, and your performance.

When I put a tank of the cheapest gas around in my car, I kid you not, the car would nearly die when you floored it from a stop. I could not beat a Toyota Corolla. Ran the tank dry, refilled with Chevron, and had the monster come back.

 

[CAP]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by RedGTS:
After waiting another 5-10 minutes, we did a third run with no leaf blower and got 415 rwhp and 459 rwtq!<HR></BLOCKQUOTE>

Good deal.

I think a factor contributing to the "creampuff mystique" is the fact that the engines are tighter when new and take time to loosen up.

Going from the '96 to the '01, I felt creampuffy. After about 2500 miles, creampuffiness was all gone.