Black Betty - Part 3 Engine rebuild
03-18-2013, 05:04 PM
#481
Great that everything is working properly!!!
On the subject of transmission loss I think the 34% you're seeing is very much on the high side....when using 28% as quoted by Streather FWHP is 294 or 312 corrected for 36 vs. 20 degree celsius.
Both loss % numbers are pretty arbitrary though, use a hub dyno for more accurate measurements or put a C4 of a known quantity on your rollers for comparison.
On the subject of transmission loss I think the 34% you're seeing is very much on the high side....when using 28% as quoted by Streather FWHP is 294 or 312 corrected for 36 vs. 20 degree celsius.
Both loss % numbers are pretty arbitrary though, use a hub dyno for more accurate measurements or put a C4 of a known quantity on your rollers for comparison.
03-18-2013, 06:40 PM
#486
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Congratulations Frank. All credit due to Nick too for getting you on the road in time for Spa and for seeing this through to a satisfactory conclusion (even though he's not completely done yet). It all looks absolutely great and hopefully will perform as well as it looks, I'm sure you will soon let us know!
My only comment regarding the end result is that it is obvious that the next significant step to making BB perform even better is a 2wd conversion; we measure around 12% drivetrain losses with a 993 gearbox on list 1B (trackday road legal) tyres.
My only comment regarding the end result is that it is obvious that the next significant step to making BB perform even better is a 2wd conversion; we measure around 12% drivetrain losses with a 993 gearbox on list 1B (trackday road legal) tyres.
03-18-2013, 06:44 PM
#487
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My car ran 335BHP (288 torques) on the chassis dyno in Gamroth's shop. The next day with the engine installed, it gave 309RWHP at the dynojet (NASA approved dyno) right down the road.
This was on race slicks and the tiny Tilton clutch/FW assy.
03-18-2013, 07:30 PM
#488
Three Wheelin'
Congratulation Frank,
This sound like you are going to have so much fun ...
Most of us refer to crank power but rear wheels is more accurate ...a good dyno is also correcting for ambient temp, the difficulty is engine temp, on an air cooled engine it becomes like a moving target for fine mapping ...obviously Bob know it's stuff ...
This sound like you are going to have so much fun ...
Most of us refer to crank power but rear wheels is more accurate ...a good dyno is also correcting for ambient temp, the difficulty is engine temp, on an air cooled engine it becomes like a moving target for fine mapping ...obviously Bob know it's stuff ...
03-18-2013, 11:29 PM
#489
Drifting
Thread Starter
Cheers gents. Plan is flat slides, remap on same dyno.
The results seem to have some inconsistencies that are no doubt too speculative to narrow down. The next two steps are about my impressions pre/ post flat slides and one day a hub dyno. Keep tuned it may get more interesting.
Whilst increased transmissional losses occur in a C4. A C4 has it's own power application advantages over C2s also.
Big thanks to all the support, advice etc.
The results seem to have some inconsistencies that are no doubt too speculative to narrow down. The next two steps are about my impressions pre/ post flat slides and one day a hub dyno. Keep tuned it may get more interesting.
Whilst increased transmissional losses occur in a C4. A C4 has it's own power application advantages over C2s also.
Big thanks to all the support, advice etc.
03-19-2013, 10:57 AM
#491
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(and snow!)
My C4 was really going well around Oulton Park on the damp RS day, and it was only when I drove my mates C2 that I appeciated just how hard the C4 had been working.
Glad it's all come together (just) in time.
03-19-2013, 12:57 PM
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http://rothsport-racing.com/Products...ide-Valve.html
A slide valve "throttle body".
Rather than the induction flap operating on the vertical axis, the slide valve operates on a horizontal axis.
Daddy wants!!!
A slide valve "throttle body".
Rather than the induction flap operating on the vertical axis, the slide valve operates on a horizontal axis.
Daddy wants!!!
03-19-2013, 02:40 PM
#495
Drifting
Thread Starter
?Wet weather, snow C4 performance is superfluous for my application. Other aspects of the C4 work for me. Power delivery, available traction, stability. Remember that road tests found the C4 in many instances quicker 0-60, specifically off the line. To me the C4 feels sure footed, rarely unsettled under braking, cornering and acceleration out of tight corners. With the HP I'm now delivering I'm confident the C4 platform will work wonders.
The important element I can take away is that power means nothing without application. Dyno plots are not real world analysis. It's clear that whilst a C4 has a higher transmission loss (est 28% loss) and weight (est + 100kg) it makes up for it in traction based on the aforementioned 0-60. Which in my book is one hell of an achievement.
Now that is not to say I am an expert by any stretch - my view is my own and based on past C2s that I have driven/ spent time with.
All this to say that the advantages/ disadvantages to both variants go far and away beyond weather.
That is not to say my needs/ views on the C4 may change. I do however feel that EvoGT2 uprights are a natural point of evolution especially for C4 track cars - that is where I feel a weakness in the platform.
Here are some great references:
https://rennlist.com/forums/964-foru...fter-mods.html
LOL! Yeah wrist is getting better by the day... looks like after a year I may just make it!!!!!!!