I'd like to know the *precise* difference between brake horsepower and wheel horsepower.

I don't really know a whole lot about aftermarket tuning. If I could keep solid reliability with FI I would do it, but my guess is that every extra bit of power you force the engine to produce reduces the realiability of that engine by an equivalent amount, assuming stock internals. Thus the reason for building up a motor.

 

i think the pulley and clutch/flywheel are different in terms of showing measurable whp because the pulley is having an effect on other pullies and is actually physically part of the engine. The flywheel is not part of the engine. It's a point where there can be drivetrain loss



bhp = engine hp. Car manufacturers use this number because it's higher and therefore sounds cooler and is more universal/accurate. But since people don't measure their power in their car by taking the engine out and putting it in an expensive engine dyno, people measure hp at the wheels

whp = hp measured at the wheels = how much the wheels turn being an indication of of real world hp at that given location/time. There's more varience with this number since there's different manufacturers of wheel dynos and elevation/temp/ECU/gas octane/alignment of planets etc

 

Dammit, I already knew that. I thought there was some super sekret definition I was missing out on!

 

BHP is really butt horsepower. its measured at the seat of your pants and can be done most anywhere. it gives the most accurated feeling and rewards with the greatest excitement/adrenaline.

 

yeah, not sure what you were expecting to hear

 

www.performancenissanracing.com

we also have a motor that does over 400HP on the engine dyno...

 

actually they are identical in the effect it has on performance. If you bolt a heavy set of wheels to your car, dyno, then swap for a light set of wheels, guess which dynos higher Rotating mass is rotating mass, regardless where on the car it comes from. The more you can take off, the more power makes it to the ground. You have not produced any gross hp...you have only increased your net.


BHP is used because that is what SAE says they have to use..and the rules have been tightening up lately (as well they should) to prevent debacles like the last Miata, and the Cobra from plaguing other manufacturers.

 

The site says "Horsepower approximately 350hp at 7000 rpm. Torque approximately 290 lb-ft at 5700 rpm.". Is this at the wheels or the crank?

 

thats for our cars that ran in Grand Am cup...

that doesnt mean other motors have not been built...

 

Please share.

 

I've been speaking with a builder that does mostly race engines. He's saying 20k CND for 400whp NA. According to him, the idle wouldn't be too bad and it would rev to 8500rpm. Cams would be custom, and I could hit it with a 75 to 100 shot for special occasions.

 

it better have upgraded connecting rods, rod bolts and probably pistons, too. Otherwise it'll rev to 8500 exactly once.

 

upgrade to ligher rods if anything...

but save your self some money... just upgrade the connecting rod bolts... youll beable to get 7800 RPM and pleanty of power withthe stock bottom end, new cams / valve... and engine mangement...

 

Thanks for the info Jason... I am sure you guys know more about VQ35DE's limitation than most of the people since you guys build vq35 engines for racing...

Also Peter Pilkington who races/builds his 350Z in Australia also said that it is fine to rev it up to 7500rpm with just the rod bolts swapped out, they haven't had any problem with the engine at all...

cheers!!!

richie

 

As far as a lightweight flywheel ADDING horsepower, that won't happen. All it's doing is freeing up lost horsepower due to drivetrain loss. That's why a car with 287 BHP will only dyno at 220-240 WHP. Say it dynos at 230 WHP. Add a light flywheel and that number will go up. Not additional HP, but just free'd HP that was already there, just lost in making **** turn. But I do understand where you all are coming from. It's not adding.

Example: My '96 Eclipse GS-T dyno'ed 199.3 WHP/216.8 WTQ before installing my ACT Streetlite. After, it dyno'ed 202.9 WHP/218.6 WTQ. Same dyno, next day, same boost, no other different mods.

 

What compression to you guys think should be used to get maximum power, but keep it driveable on 93 octane? I was thinking maybe 12.0:1 or so. I would like to be able to get Porsche GT3 power or more and it is running a 11.7:1.

 

What kind of labour is required to swap the rod bolts out?

Is it just a matter of dropping the oil pan, swapping the bolts, and then installing a new oil pan gasket?

 

The crank. Hence the "approximately" 350hp. Keep in mind though, that this is with very minor modifications over all. Talking with Unitech, and having a copy of the GA rules handy, it is amazing how limited they were in building this engine. The 350hp is mostly the result of the Motec, custom exhaust, Injen intake, and a LOT of balancing of the recipricating assembly. They were allowed to lighten only minor things like the cam gears, but not the stock flywheel and balancer. They hadn't, at the time, recieved approval to use the NISMO heads, so they are stock, and no aftermarket cams allowed. (this might have changed since last season) Basically, only intake, exhaust and ECU are free in the series. I can easily see them building a 400hp VQ35 without all the restrictions in place. Now if they would just sell one to me....

 

With 93 octane I would say 11.5 and anything over and your pushing the limits of the fuel.

 

ACtually the Wheel HP *should* increase due to the decreased lose in the drivetrain. Now, I am NOT saying that the engine will put out anymore HP then before, I'm just say ing that more of the power would make it to the wheels.

Are you talking actual top speed, or theoretical top speed?

Theoretical top speed would remain the same, but actual top speed should increase.

Ok, this is just a hypothetical situation.

Could you list what you would do to the engine with a $20k limit, excluding FI/NO2, and what would the expected power be?

ANyone make a stroker kit, or just the crankshaft? If so, how much? What is the displacement increase?

What's the compression ratio? Any room for an increase? Like close to 11:1. Of course you'd want to increase to 93 OC gas.

Any room to overbore the cylinders? If so how much?

How about changing out the pistons and rods for lightweight/stronger aftermarket ones? That'd allow the engine to rev a bit quicker, correct?

Head port and polish? New cams? Change the computer with a custom EFI system. Possibly multiple throttle bodies, this would take you over $10k though, and it'd be more appropriate for FI.

ANyways, you get the point. I'm just asking what can be done, and what will the results be?