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Will show that the TT provides a fatter midrange while giving up at the top.
Was your buddy on wastegates only or any kind of boost controller?
But yeah.twin scroll is the way to go now.
Electronic boost controller.
Originally Posted by mafoor
This has to be the new pump gas record. Details on the build? (piston/rods/head gaskets etc.)
Cosworth pistons CR 8.8:1, BC 625+ rods, HR headgastkets, L19 ARP bolts, JWT C8 cams etc. The key is making power with lowest possible boost. Btw. our highest octane pump gas is RON 100.
Cosworth pistons CR 8.8:1, BC 625+ rods, HR headgastkets, L19 ARP bolts, JWT C8 cams etc. The key is making power with lowest possible boost. Btw. our highest octane pump gas is RON 100.
i did 850 on stock heads and stock cams with 8:1 compression it definitely isnt about making the most power on the lowest boost. the billet wheels of today dont take advantage of the extra area offered by being billet until upper pressure levels. every manufacturer will tell you outright they dont flow anything more than the cast version till above 30 psi.
now onto this....... i would seriously want to see the track times 800 whp for those wondering his fuel is equal to 93 octane(well almost 94) by the way things are done in the states. even with a 100% efficient intercooler and a 100% efficient turbo neither of which exist the engine would have to be putting out 320 whp before turbocharging to hit this number at 22 psi.......(800/2.5 bar) given a more real world number of around 125% power increase at 1.5 bar which is very resonable and likely to take into account the turbo and intercooler not being 100% efficient that would mean 355 whp at the engine before turbocharging........ thats 320-355 whp from a 8.8 compression engine at 7k rpms isnt going to happen.....
before someone jumps in with "yah but turbo x wont make the same airflow at xx psi as turbo y at xx psi!" this only applies to undersize turbos. yes on a vq35 trying to use say a single gt35 at 22 psi vs a 67mm at 22 psi the 67 will make more power, jumping into a even larger turbo at 22 psi wont however make any more power because the 67 is capable of supplying the air needed and while something larger than a 67 would make more power it would also require more boost pressure as well its a complex relationship that dosnt apply here.
so i would really like to see the claimed power backed up by track times because the claimed power at claimed boost dosnt make any bit of sense from a engineering and engine building standpoint. its fully possible to make the power on pump but im betting the boost reading is wrong or the dyno needs recalibrated.
it took me 32 psi to hit that where the billet wheels on average see a 20% boost over cast wheels. below that they flow similar to cast wheels and i ran a very very aggressive timing map.
im not trying to degrade him or anything, its very possible to hit 800 on pump this dyno just seems a bit fishy for only 22 psi. spoke to some other tuners and shop owners and the consensus seems to be European dynos seem to read about 15% high possibly trying to estimate engine horsepower vs actual wheel power. ive not had a customer over there nor been to any shops over there so i cant give my own input. personally i think engine hp is worthless anyway though other than on a actual engine dyno to establish a tune.
the point is twin numbers are well known here on chassis dynos for wheel horsepower comparing your dyno which is attempting to estimate engine horsepower to those dynos of wheel horsepower its really not impressive at all and very similar in terms of spool and power under the curve.
second using a chassis dyno to estimate engine horsepower is about as accurate as closing your eyes and throwing darts at a board. drivetrain loss is NOT a set percentage meaning estimating bhp on a chassis dyno is impossible. different drivetrains or heck even different gear ratios will have different drivetrain losses. on top of that things like inertia losses from the weight of rotating parts are a set amount of power consumption that dosnt change with power. for instance if it takes 15 bhp to turn a gear based on its weight it will consume that 15 bhp at 100 whp or 10000000 whp. friction is where a percentage comes into play, as well as windage losses from fluid splashing around inside drivetrain components. the percentage of loss in a drivetrain goes down as power goes up because of this. reality is your dyno is absolutely worthless for any meaningful comparison you could be 400 whp, could be 650 whp we dont know because its calibration is nothing but a guess.
third, attempting to estimate bhp is stupid, the bhp of a engine is completely meaningless unless the engine is on an actual engine dyno and trying to establish a base tune. there will be drivetrain losses, the whole point of wheel horsepower is that wheel horsepower is USABLE horsepower to propel the car forward.
fourth the track times show exactly why your dyno is worthless, 12.27 quarter is terrible at the claimed power, stock block cars making 450 whp or less are beating that and the trap speed shows something too thats about 124 mph....... which would be on par with a ~525 bhp car but thats even a shot in the dark because again bhp is worthless. we have cars ~450 whp doing that trap speed though.....
honestly knowing that this entire thread essentially became worthless
in fact considering your dyno is estimating bhp cux's twin turbo car is making more power and has faster spool up at every single data point with less boost. so again your comparison is kinda a waste and dosnt show us anything the car needs to be put on a proper dyno.
I was gonna post up about KevinApex's car doing 740 whp back in 2007 as I was there for that dyno session and got a ride in it, but I guess in fairness that was SAE correction up in Denver. Uncorrected I think his was at 595/512 on 91. But in fairness that was still pretty bitchin all things considered for uncorrected power on a DE no less. I thought I recall a guy in the 7's in Cali on a modified JWT back in the day but who knows, with E85 pump gas these days, stupid power is possible either way.
in fact considering your dyno is estimating bhp cux's twin turbo car is making more power and has faster spool up at every single data point with less boost. so again your comparison is kinda a waste and dosnt show us anything the car needs to be put on a proper dyno.
I have personally tuned both cars, and on the same dyno. So this comparison is apple vs apple..
"My" dyno does not estimate bhp or doing calculations of WHPx1.15 type, it measures losses using the drivetrain loss method (doing a coastdown while leaving the transmission in gear with the clutch in). Yes, it's not absolutely accurate, but most of the stock cars I've measured are in +-2 BHP of declared power. Again, I really do not want to argue with you or anybody else here about this subject, because it has been discussed many times on every car enthusiastic forum without consensus. Dyno is a tool, and like any other tool, if used properly you will gain.
At the end of the day believe what you want, I have absolutely no reason to lie or promote one setup against other. Just wanted to share my experience.
1) no one cares that you tuned both cars, your twin example performs worse than what they are known to be capable of. simply because you couldnt get it to work right dosnt mean squat we have and we know the results.
2) no your dyno dosnt measure drivetrain loss, hate to break it to you but coasting down with your transmission in gear and clutch in is measuring absolutely nothing. in fact with that comment im 100% confident you dont understand how drivetrain loss works at all. a)if its an inertia dyno which by your description im guessing it is, it measures acceleration, not deceleration. b)if the drivetrain is not under power it is impossible to measure proper friction losses since those are percentage based losses. drivetrain loss isnt a set percentage, nor is it a set number its a combination of the two and what you have described has zero ability to measure it. the ONLY way to measure drivetrain loss is to put the engine on a engine dyno and dyno it, then install in car and chassis dyno it. frankly i laughed at this and im thinking you have zero clue how your dyno works.
3)no your dyno isnt within 2 bhp, hell standard deviation for a dyno is 5-10 hp with the same conditions on the same engine, in the same car dynos arnt accurate to start with
4)dont argue with a mechanical engineer on how machines work and the science behind them.
in conclusion? the entire thread has become useless the moment we realized your dyno is doing nothing but guessing to try and show a big number. as i stated your supposed numbers dont match up with the track times you should have been running at a given power. set the dyno up PROPERLY and come back.
Originally Posted by tcode
I have personally tuned both cars, and on the same dyno. So this comparison is apple vs apple..
"My" dyno does not estimate bhp or doing calculations of WHPx1.15 type, it measures losses using the drivetrain loss method (doing a coastdown while leaving the transmission in gear with the clutch in). Yes, it's not absolutely accurate, but most of the stock cars I've measured are in +-2 BHP of declared power. Again, I really do not want to argue with you or anybody else here about this subject, because it has been discussed many times on every car enthusiastic forum without consensus. Dyno is a tool, and like any other tool, if used properly you will gain.
At the end of the day believe what you want, I have absolutely no reason to lie or promote one setup against other. Just wanted to share my experience.
So I did 11.4 sec quarter mile with bad 60 ft. There are no true drag strips around, this was on an old plane runway. Trap speed is "low" because I reached 8k rpm in 4th gear and hitting rev limiter up to the finish line.
When I shift to 5th gear, trap speed is 214-215 km/h.
Oh, btw. I have a roadster version, which is heavier than coupe, it's fully loaded, nothing stripped from it, I didn't even clean the trunk .
One funny run against Go kart loaded with R1 engine (yes, I did catch him before finish line )
Not easy making clean power on pump that's for sure!
05-25-2016, 12:36 AM
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