Don't worry, we managed to get a video of the third run as well Third run produced the best numbers but all three all were very consistent...
If you have a decent computer speaker system, it will give you a good idea of how the Indy Northstar sounds (one of my favourite features of the newst project) I decided to share the results here on the build thread and will post the graph too. Hopefully I'll get some positive ratings and useful feedback versus regretting sharing
Fiero2m8
you should have shifted to fith as I could here the rev limiter kick in before you hit top speed with the 4:13 gear fith is needed to reach top speed
you also are short on timming you need 38 deg. total at 6000 rpm
[This message has been edited by bubbajoexxx (edited 08-22-2012).]
Fiero2m8
AUG 22, 06:28 PM
quote
Originally posted by doublec4:
Nice!!
Sounds great and looks incredible. Very awesome to see this car come so far. Great work Ryan.
Thanks, you have been proactively contributing to this thread since 2004 and I appreciate your feedback!
Cheers, Fiero2m8
Fiero2m8
AUG 22, 07:11 PM
quote
Originally posted by bubbajoexxx: you should have shifted to fith as I could here the rev limiter kick in before you hit top speed with the 4:13 gear fith is needed to reach top speed you also are short on timming you need 38 deg. total at 6000 rpm
Hi Joe, I asked about that and they said that the dyno is most accurate when you are in a gear with a 1:1 ratio. Assuming that the stock porsche "V" gear is still in this transaxle, 4th would have a ratio of 0.93 (the closest). I agree that top speed will be achieved in 5th due to the final drive ratio I'm using.
Sorry I forgot to post the timing settings - here they are (and yes I kept my foot in it until my preset 7500 rpm rev limit engaged):
With 10 degrees mechanical timing plus these settings I thought I was at 34 for my baseline runs.
Will
AUG 22, 07:51 PM
quote
Originally posted by Fiero2m8:
I asked about that and they said that the dyno is most accurate when you are in a gear with a 1:1 ratio.
Umm...
"Accurate" means a lot of things... in a front engine rear drive car like a Camaro or Corvette, the 1:1 ratio means that the input shaft of the transmission is locked directly to the output shaft and the power doesn't go through any gear meshes. This means that the 1:1 gear has the lowest frictional parastic loss.
In a transmission like the Fiero's or like the Porsche's, there is no "direct" gear. ALL of the ratios transfer power through gear meshes. No gear has an advantage over any other in terms of frictional loss.
However, there is a balance of inertial losses that must be considered. It takes energy accelerate the driveline rotating mass. That mass is split between engine speed rotating mass and wheel speed rotating mass. The engine speed rotating items that matter are the clutch and flywheel. The wheel speed rotating items that matter are the brake rotors, wheels and tires.
So if the gear ratio is numerically large and the acceleration of the engine speed rotating mass consumes more power than acceleration of the wheel speed rotating mass, upshift. If the wheel speed rotating mass requires more power to accelerate, downshift.
Of course the easiest way to do this is to do a complete pull in each gear in order to see which one gives you the best numbers.
Fiero2m8
AUG 22, 08:45 PM
Thanks Will. Yes he basically said 4th gives the best result. Almost all other cars tested were new Camaros.
I also heard many guesses on what flywheel hp would be. Quite a range!
Fiero2m8
AUG 22, 10:07 PM
Picked up the HID lights and harness to install into the doublec4 buckets:
Hopefully will work on them this weekend.
Fiero2m8
AUG 23, 12:03 AM
Thanks Will. Yes he basically said 4th gives the best result. Almost all other cars tested were new Camaros.
I also heard many guesses on what flywheel hp would be. Quite a range!
Will
AUG 23, 08:35 AM
quote
Originally posted by Fiero2m8:
Thanks Will. Yes he basically said 4th gives the best result. Almost all other cars tested were new Camaros.
I also heard many guesses on what flywheel hp would be. Quite a range!
What I was saying is that because your car doesn't have a "direct" fourth, you'll have to experiment to see which gear does give the best results. The 1:1 "rule" does not apply.
Fiero2m8
AUG 23, 02:31 PM
quote
Originally posted by Will: What I was saying is that because your car doesn't have a "direct" fourth, you'll have to experiment to see which gear does give the best results. The 1:1 "rule" does not apply.
Yes I agree with your explanation, sorry for not clarifying I understood. Once I book a dyno tuning session, I will be sure to find the best gear for my application prior to making changes to the tune.
Will
AUG 23, 03:19 PM
It's pretty much academic... it could give you higher numbers, but as long as you use the same gear every time, you can still compare results.
