792 rwtq at 3400 rpms!! Further testing of the LETHAL 1000

[LTHL VPR]

Well, as we wait for injectors, I decided to spend some more time on the dyno today and tune the car in the lower rpms where there is plenty of fuel to play around with. Surprisingly, I was quickly able improve upon the numbers from earlier this week.

Here is what I was able to accomplish today:
2600 rpms: 310 rwhp, 620rwtq
2800 rpms: 350 rwhp, 660rwtq (Before: 290rwhp,550rwtq)
3000 rpms: 400 rwhp, 700rwtq (Before: 310rwhp,550rwtq)
3200 rpms: 460 rwhp, 760rwtq (Before: 350rwhp,580rwtq)
3400 rpms: 510 rwhp, 790rwtq (Before: 405rwhp,630rwtq)

These numbers are SAE corrected and it was pretty warm today....
Still working on dealing with a flattening of the curve from 3400-4300 rpms. Considering my peak torque before the supercharger was at 4400 rpms, I would expect peak torque to occur no lower than this....

Probably wait until we receive the injectors to spend more time tuning since I will have to re-tune everything anyway.

Just thought I would keep you posted. Given the fact we didn't even hit 4lbs boost in this range, I am satisfied with these numbers so far. Now I need to concentrate on the last 2500 rpms.

Thanks!
-Wayne

 

[Torquemonster]

On 4psi - those are stomping numbers Wayne. Be interested to hear your comments when it's all tuned in at 6-7psi about how much throttle response is lost due to the drop in compression - I'd expect not much once under way - maybe a bit from idle to 2500rpm?

 

[LTHL VPR]

I can't wait to get everything dialed in too!!

Actually, we made those numbers on less than 4 lbs boost! We didn't hit 4 lbs until around 3800 rpms.

I did have a chance to drive it already. I don't think it lost much in the low end, off the line, but I wasn't dropping the hammer either. I probably wouldn't mind if it did though, because then the tires would have a better chance of planting off idle.

I like to think of throttle response in the following manner:
you're driving down the highway at 60mph (4th gear) or an access road at 30-40mph (2 or 3rd gear) and you PUNCH it! Some cars slowly build power and torque and it takes a bit to get them going. In these instances, I find my car really takes off!! Usually I am driving atleast at 2500 rpms or so, and the supercharger is able to build small amounts of boost down low so I don't think I lost anything in that area...

I'll keep you posted!
-Wayne

 

[Torquemonster]

I can imagine Wayne! From 2500rpm that motor will bark!

By throttle response I was meaning more like going from idle to 6000rpm in neutral at the slap of the throttle.... how do i explain how some motors wind up while others bark instantly....

...you know how some cars - especially typically old Holley equipped muscle cars - when you slap the throttle savagely at idle - they first say "what? - you've got to be kidding ... then they fart, climb reluctantly at first then start to roar.... (well - it's all done in under a couple of seconds but its relative). Most modern injected motors are not a lot more responsive for some reason - they don't fart, they'll simply take a split second to consider the request - then rev. The other extreme is an alcohol injected sprint car engine with mechanical injection - they bark from idle to redline in a split second - throttle response is instant and savage if you smash your foot down - like there was a rod welded between your right foot and the rpm counter.

As a guideline - I ran a Predator carb on a 440 Mopar - they have a variable venturi that gives them very good throttle response. It would snap from idle to 7000rpm in about 1 second flat. The response meant that the engine behaved precisely as quickly as the foot moved... prod the pedal smoothly and the motor climbs in proportion, but stab it and it leapt like it was alive.... Loved that carb for its response - made the car feel like it was a living breathing monster. That kind of response turns a lot of heads because of the crisper, sharper engine note that comes with it.

If you get an 8+ litre V10 that crisp - it'll have a sound all of its own! Torkey Likey!

 

[LTHL VPR]

Now, I know what you are talking about....
I have stock rear end gear ratio which is plenty fine for the power I am making. The car spins up fast; the aluminum flywheel helps in this department too. Light throttle blips can easily hit high rpms even now...

Once I receive the injectors and we can finish tuning the car, it will be very interesting to see how it behaves, or should I say 'MIS-BEHAVES' on the road!

With almost 800 rwtq at 3400 rpms using a centrifugal supercharger, it doesn't look like I will need to worry that much about it, but we will know for sure soon.....
-Wayne