I'm taking my xjr to the dyno this saturday. I thought it would be fun to have a friendly competition and guess what I'll put down. Mods are in my signature. My guess...338whp and 394 ft lbs...I like to mix it up, lol

What's your guess?

 

GOOD DEAL ! make sure u get fresh gas before you go. im predicting 345hp and 410 lbs torque

 

I hope so cinci...I better add my torque guess

 

Mustang dyno - 313rwhp, 327ft lbs
Dynojet - 328rwhp, 342ft lbs

When will you be taking your car there??

 

Tomorrow!

 

Probably stock numbers, maybe 10hp more.
However, your 1/4 mile numbers say much less than stock, about 320 bhp.

 

depends on what dyno you use, Dyno Dynamics, and Mustang dynos are always lower that Dyno Jet, But they are much more realistic to actual numbers. So what are you gonna dyno on, real world, or overly optimistic?
And then what are the correction factors used for altitude, humidity temps etc..

 

well, it was also my first time running a car at the track, and had a bit of wheel spin. That number will improve. I don't expect big gains from the mina exhaust and intake

 

Looking forward to hearing the results!

 

Well, today is the big day ! Im also curious what will be the airfuel ratio will be with the hp that will be made today.

 

Results are in...

304whp & 310ft lbs
I was a bit disappointed. I did find out that the xjr suffers from heat soak like a mother...That seems to be a big problem right now. I will upload the graph soon

 

 

What were the ambient temperatures during this run? And do you know the elevation of the shop where these numbers were taken?

There can be a number of different factors that could result in a lower reading...

Assuming a 20% drivetrain loss from the automatic gearbox, you are sitting at exactly 380bhp to the crank and 387.5ft. lbs to the crank. These numbers are lower than stock which is why I think the weather and conditions may have had a huge influence on your numbers....

 

Wow ! I dont like the HUGE dip between 3200 rpm's and 3600 rpm's thats some missed hp. right there.

 

I wonder whats can be done to lessen the "engine heat soak" issue with these XJR's .

 

I'm pretty sure that's just from him feathering the throttle. He said he was having trouble with it, too much throttle and it would downshift

a bigger better heat exchanger...I'm going to be looking into having one made

It was a chilly day, I would say ambient temps were only in the high 60's...elevation was around 600 ft above sea level

 

Well I took a closer look at the dyno chart and noticed that the dyno your car was run on is manufactured by Dyno Dynamics...which is widely known as the "Heartbreak Dyno".

The reason for this is that the Dyno Dynamics dyno reads significantly lower than a dynojet and even a mustang dyno.

Somebody correct me if I am wrong but the Dyno Dynamics dyno usually reads 10%-15% lower than a dynojet. If we take the average of these two, at 12.5%, your wheel horsepower on a dynojet may be around 342rwhp and 349ft. lbs.

These numbers sound about right for the modifications you have done to the car. That intake, when the hood is open, should give you a healthy gain...the exhaust may have helped as well.

My car, with just a 1.5lb upper pulley and oil that was run for 7500 miles made 340rwhp and 346ft. lbs on a dynojet.

Hopefully this makes you feel better about that 304rwhp reading!

 

man-o-man, I hope you are right. That does make me feel alot better

 

whats a heat exchanger ? I never heard of this before .

 

I think he was referring to the front mount intercooler.