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| Project 3400 Roller Cam Block (Page 55/82) |
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Joseph Upson
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OCT 07, 02:04 PM
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13.9 is probably a little too lean even for naturally aspirated, it's a range, some motors like it and some don't. I'd aim for 13.2 tops unless you've had benefits from it in the past. Something as simple as the straps being tighter on the rear end holding the car down, pulling it down further can make a difference in the results especially if your car is lowered already and the inboard axle angle is increased further towards the binding threshold that has caused some of our cars to shake/wobble on acceleration.
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joshua riedl
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OCT 07, 02:24 PM
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I recently read a hot rod magazine that had an article where they were track tuning a car. They ended up making timing and fuel changes for the best times. After the fact they went to a dyno and found it was running richer than what's commonly used so they leaned it out. I couldn't figure this out since the richer it was the faster it was. Something to think about.
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lou_dias
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OCT 07, 02:55 PM
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| quote | Originally posted by joshua riedl:
I recently read a hot rod magazine that had an article where they were track tuning a car. They ended up making timing and fuel changes for the best times. After the fact they went to a dyno and found it was running richer than what's commonly used so they leaned it out. I couldn't figure this out since the richer it was the faster it was. Something to think about. |
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For cams with lots of overlap, that may be true. Even on the old graph you can see the power go south with the A/F ratio past 3600 rpm...
What I was saying is that with my TPI intake, aka the Fiero intake ported and shortened, I made 187/249 @ 4100-4200 rpm. Changing to a larger V8 throttle body and Trueleo I lost almost 20% of my torque... For poops and giggles, I should get the DAWG intake neck mod and swap back and see what happens past 4200 rpm now... I mean, I've has nothing but problems since I ditched the Fiero intake but if that TPI effect is real ... well that would be something.
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Joseph Upson
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OCT 07, 04:35 PM
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| quote | Originally posted by lou_dias:
Changing to a larger V8 throttle body and Trueleo I lost almost 20% of my torque... |
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Intake velocity, you can have too much flow for your setup in the same manner that you can have too much turbine housing on a turbo requiring a very high rpm efficiency to make use of it. I ruined a perfectly good set of 350 heads by opening up the runners, it was a dramatic before and after hard lesson where all else the same on the motor it was lacking an awful lot of low end torque just like the experienced machinist warned me against before I did it.
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Will
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OCT 08, 09:26 AM
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| quote | Originally posted by joshua riedl:
I recently read a hot rod magazine that had an article where they were track tuning a car. They ended up making timing and fuel changes for the best times. After the fact they went to a dyno and found it was running richer than what's commonly used so they leaned it out. I couldn't figure this out since the richer it was the faster it was. Something to think about. |
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Cars tend to run leaner in the real world than on the dyno
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lou_dias
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OCT 08, 01:02 PM
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I guess that also explains why I haven't snapped any axles since switching intake+TB... :/ In theory, that's supposed to be a good thing...
I'll be hunting for a machine shop this weekend, me thinks. I got all off-season to swap back and get some dyno testing done...[This message has been edited by lou_dias (edited 10-08-2013).]
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lou_dias
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OCT 10, 12:44 AM
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As you can see, the hp peak is fairly flat between 4800 and 5200. A/F ratio doesn't go above 14.0. I've already tweaked the a/f ratio down from 4400+ but unless no more dynos for a while me thinks. this was on Oct 5th.
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lou_dias
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OCT 13, 07:49 PM
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carbon
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OCT 14, 10:03 AM
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Nice!
Like the comment about the guy you beat in the first video.
"Ha ha... isn't that the guy who did the donuts and everything..."
I also realized that I have been pronouncing your name wrong in my head.  [This message has been edited by carbon (edited 10-14-2013).]
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Blacktree
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OCT 14, 11:41 AM
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Nice runs. Too bad the car broke on the last one.
On a side note, with all the money you spent on dyno runs, you could probably have your own datalogging setup by now.
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