Dyno update
 

Have been to the dyno yesterday for a run, and the results where 506 and 512 rwhp.

Originally my car made about 315 rwhp (about 379 bhp), and now about 510 rwhp (about 614 bhp), so that is in total 234 more hp than I originally started with (all using a 17% drivetrain loss).

Here is the Dyno slip.
https://www.jaguarforums.com/forum/p...e3/#post472716

Impressive. You have put together quite a brute there, but a beautiful one.

Yes, she can be indeed ;-)

Congrats, Andre.

Would you happen to have a corresponding torque number and graph?

(Or, does the "506" number represent torque?) Thanks, Ed.

I have one, but it isn't scaled right so would only confuse. I was just going in for a quick run, so we didn't spend time to configure the rpm scale right.


But calculating from the HP at 4450 rpm, it would be about 483 lbf to the wheels (so probably about 500 lbf lower in the rpm, but that is just not measurable on a chassis dyno).

Peak HP was about 5900, so there was about 463 lbf to the wheels, pretty straight line ;-)

Can the rest of the drive train handle the power or is there a risk of breaking drive shafts, differentials, etc. if you really kick it?

Doug

Someone has to pinoneer, and I kick it every day :icon_razz:

Just another restatement of why i want to take off the mp90 eaton off my custom install on the nissan frontier and go to a twin screw. Im at 330rwhp for a 4.0 v6. But i dont want to spend the money buying a kit for the blower only to fab the rest as youve done for the jag. That would be wasted money. Got any spares andre? :) Good job

pm sent

What rpm did you run it to?

Well if the hp curve falls off before redline, I bet it's your stock exhaust choking the power.

Andre;

Great job!!!

That is with the 'medium' sized pulley right?

Do you have any idea what the numbers would be if you used the 'small' pulley?

I think I have that in the right order...more power the smaller the pulley, ie more supercharger rpm's...right?

I heard from jaxkr in Boston that there was one smaller pulley than the one you are running.

cheers,

jj

Pulleys are available from KB in 1/4" increments from 4.25" to 2.5"; not just a 'medium' or 'small' one.

@JJ,
You are correct with the upper pulley. Actually you can get any size upper pulley, but to give you an idea for a 4.2 engine (lower pulley); I would recommend not going smaller than 3.25”. I now have a 3.0” on that lower pulley, and you can go to about 2.5”.

Just going from a 3.0” to a 2.8” would add already 2 psi, and going from 3.0” to 2.5” would be 7 psi extra. The kit/supercharger is not the bottleneck, but you need serious engine mods to run these pressures, and also much higher octane fuel.

@SteveM,
For me it goes to show that the stock exhaust with the crimped pipes over the rear axles can handle much more power then sometimes is suggested.

But I think you are right, for these levels I am at now, headers and a larger exhaust would more than likely yield some good extra horses again.

I like the stock exhaust sound note/volume I have now with the sports catalysts. I just drive too much and can’t live with louder noises/ droning from it. I hade once a x-pipe system, which was just to loud and drony.

Is it perhaps a soft rev limiter that you are running up against?

After all 5900-6200 is only 300 rpm.

It can actually be many things but not a rev limiter, the exhaust could very well be one, but some light knocking also, as then the ECU will slightly retard the ignition, causing some power loss. The latter can be easily tested with race fuel, and then I can also up the boost again, that will give again a lot of new data. For now I will just enjoy it for a while as when driving you are not getting at 6000 rpm anyway as it will shift before there.
Have a look at some 5.0 SC dynos in the link below, there you will see that the power level is even longer leveled, i.e. more than 500 rpm (and even dropping …), not just the base tune, also the tuned one.
https://www.jaguarforums.com/forum/x...e3/#post472549

Thanks Steve;

I had only ever heard of three sizes of pulley, perhaps because that is all that is usually listed by after market tuners.

Avos;

So you are OK at this size pulley 3.0 on premium fuel and basically stock everything else, right?

What is the OEM size pulley and how much do you calculate that you have increased PSI in the super charger from stock?

cheers,

jj

These are simple pulleys to make actually, so any size you like can be made (for half the price of the Eaton pulleys ;-). A stock Eaton is iirc about 2.93" or something.

For a 4.2 car I would not go smaller with my kit than a 3.25” one, and a 4.0 car not smaller than 3.0", unless you are going to use race fuel, alky kit or make other engine modifications.

Ahhhhh that means mine will be slower than yours.......

OK. I do like the idea of the engine staying together.

Thanks as always,

jj