2016/01/20 14:32:25
Jaemus
I see what you're saying, but it still seems a bit extreme to me.
 
Worth noting is that on the calculator Glenn provided, you get 577 crank horsepower.


In any case, my suggestion is you tune it again on 85% ethanol and/or increase the boost some more until you eclipse the Veyron just above you in the list there :)
2016/01/20 16:51:00
robk
Remember that the 620 crank hp that I mentioned was assuming a little bit more than 378rwkw if there was 85% ethanol in the tank instead of 68% ethanol. The car was tuned on 85% ethanol, but that was before MRC replaced their dyno rollers to help eliminate wheel spin. With the new dyno rollers I've only had the car on their dyno with 68% ethanol at a dyno day and that's when it made 378rwkw. I'm sure that it will make about 385-400rwkw if I put it back on the dyno again with 85% ethanol and no extra tuning. The flex-fuel tune is already set up to automatically (and safely) increase the boost and ignition advance with any increase in ethanol content. 
 
I should be able to get over 400rwkw on E85 with a few more psi of boost and/or more ignition advance, which would be awesome, but I have to decide whether I want to put that extra stress on the engine and transmission. I've heard of E153 transmission gear teeth shearing off with about 450+rwkw, so I want to stay well away from that sort of craziness. If I had just a little bit more power then that would help me to get a 10 second pass at the drags, which is why the idea crossed my mind in the first place, but I should be able to do it without the extra power. I was toying with the idea of using my launch control button to also allow some more power to be applied only while the button is pressed. 
2016/01/20 17:24:53
92 Hard Top
robk
Remember that the 620 crank hp that I mentioned was assuming a little bit more than 378rwkw if there was 85% ethanol in the tank instead of 68% ethanol. The car was tuned on 85% ethanol, but that was before MRC replaced their dyno rollers to help eliminate wheel spin. With the new dyno rollers I've only had the car on their dyno with 68% ethanol at a dyno day and that's when it made 378rwkw. I'm sure that it will make about 385-400rwkw if I put it back on the dyno again with 85% ethanol and no extra tuning. The flex-fuel tune is already set up to automatically (and safely) increase the boost and ignition advance with any increase in ethanol content. 
 
I should be able to get over 400rwkw on E85 with a few more psi of boost and/or more ignition advance, which would be awesome, but I have to decide whether I want to put that extra stress on the engine and transmission. I've heard of E153 transmission gear teeth shearing off with about 450+rwkw, so I want to stay well away from that sort of craziness. If I had just a little bit more power then that would help me to get a 10 second pass at the drags, which is why the idea crossed my mind in the first place, but I should be able to do it without the extra power. I was toying with the idea of using my launch control button to also allow some more power to be applied only while the button is pressed. 


What about putting sensors on your 4 wheel to control your launch.
2016/01/20 17:32:05
Hoonsy
I make one comment and you guys get all technical with it. Not all of us are good with stats and figures dammit haha
2016/01/20 18:45:25
Admin
Pumping up your rear tyres to 50psi will give you more power on the dyno :-)
2016/01/20 19:12:30
MCT_MR2
I have built a few evos in my time where the tyres and strapping techniques can vary the reading on a dyno by 110wkw.

As rob said, the condition of the knurling on dyno rollers come into play, tyres used (harder compounds will give a better reading than softer tyres, semi slicks and slicks are prone to overheating and sliming up on the dyno.)

Hubs dynos are accurate for calculating drivetrain loss, if you can run an engine on an engine dyno, and take tyres out of the equation.

Run a jockey wheel and do speed dependant boost control rob, then feed the rear wheels speeds into the ecu and do traction control vs the jockey wheel with a varying slip allowance. Front wheels can be unreliable, and gps is too slow to react.
2016/01/20 21:23:02
92 Hard Top
What size injectors do you run? Thinking of getting bigger ones, could keep engine temps down.
2016/01/20 22:11:32
robk
I know exactly what you're talking about with the multiple wheel speed sensors and traction control, because that was one of the highlights of my university thesis, which helped me get my previous job at Adaptronic. 

People have also suggested boost by gear, which I can already activate in my ECU at any time (I already have gear detection working), but I enjoy the challenge of trying to handlle those things myself with the right foot instead of letting the ECU do it.

On the topic of tyres getting sloppy on the dyno...yep, my Federal 595 RSRs turned into a sloppy mess on the dyno. 

grosso
What size injectors do you run? Thinking of getting bigger ones, could keep engine temps down.

I have Injector Dynamics ID2000, which are much bigger than necessary. Installing bigger injectors won't change your engine temps unless you richen the fuel mixtures, and even then it won't make much difference.
2016/01/20 22:22:00
Admin
True. You are still squirting the same amount of fuel into the engine no matter what injectors you use. The only reason to use larger injectors is when you have more power like Rob and need more fuel than what your injectors can provide at 100% duty cycle.
2016/01/20 22:32:08
Jaemus
robk
Remember that the 620 crank hp that I mentioned was assuming a little bit more than 378rwkw if there was 85% ethanol in the tank instead of 68% ethanol. The car was tuned on 85% ethanol, but that was before MRC replaced their dyno rollers to help eliminate wheel spin. With the new dyno rollers I've only had the car on their dyno with 68% ethanol at a dyno day and that's when it made 378rwkw. I'm sure that it will make about 385-400rwkw if I put it back on the dyno again with 85% ethanol and no extra tuning. The flex-fuel tune is already set up to automatically (and safely) increase the boost and ignition advance with any increase in ethanol content. 
 
I should be able to get over 400rwkw on E85 with a few more psi of boost and/or more ignition advance, which would be awesome, but I have to decide whether I want to put that extra stress on the engine and transmission. I've heard of E153 transmission gear teeth shearing off with about 450+rwkw, so I want to stay well away from that sort of craziness. If I had just a little bit more power then that would help me to get a 10 second pass at the drags, which is why the idea crossed my mind in the first place, but I should be able to do it without the extra power. I was toying with the idea of using my launch control button to also allow some more power to be applied only while the button is pressed. 



Indeed, fair enough if that's the figure you feel comfortable with. Well, to get to just above the Veyron on that list, you only need 646bhp. (Veyrons are indeed heavy!) So I think you're safe there, it's probably only 1-2psi or a couple of degrees of timing more and the gearbox is still in safe sub 400kw territory ;)
<< ..137138.. >> - Powered by APG vNext Trial
© 2026 APG vNext Trial Version 5.5

Use My Existing Forum Account

Use My Social Media Account