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Old 08-04-2016, 03:25 PM   #1
no694terry
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Default Vehicle weight and gearing vs Engine Load g/rev

Would vehicle weight effect engine load g/rev?

I'm curious because i have a 50#/min turbo at 24 psi and only seeing about 3.5g/rev. Seems low to me, could it be from 4.11 gearing in a 2500 pound car?
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Old 08-04-2016, 04:37 PM   #2
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Prob don't see a lot as its not cramming air in the engine at low/mid rpm with your engine setup. What rpm do you see 3.5 and how long does it hold? what gear was the pull done in?
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Old 08-04-2016, 04:52 PM   #3
no694terry
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Quote:
Originally Posted by rexworx View Post
Prob don't see a lot as its not cramming air in the engine at low/mid rpm with your engine setup. What rpm do you see 3.5 and how long does it hold? what gear was the pull done in?
3rd gear from about 4200 to 4300 then tapers down to 2.5g/rev by 7k

https://docs.google.com/spreadsheets...?usp=drive_web
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Old 08-04-2016, 08:32 PM   #4
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oops nevermind

Last edited by Shiftace420; 08-04-2016 at 08:40 PM.
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Old 08-05-2016, 07:11 AM   #5
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Looks like it could be due to your maf scale. If you set your injector size too small (aka scalar too large if using ATR), you probably had to scale the maf smaller to compensate and obtain the proper IPW.

Your MAF scaling looks like that of a VF turbo, where it's only hitting around ~285 g/s at red line. I wouldn't be too concerned though because if AFR and timing under WOT are both good, then it's not really an issue. It's kind of like when people use the MAF hack to tune around the 300 g/s limit on the 16-bit ECUs.

Edit: Another thought, were you tuned on E85 previously and now running normal pump gas without rescaling the injectors? Your MAF scaling is about 70% of what it should be, so you should be flowing around 400 g/s at red line (285*1.42), which makes more sense as that's around 52 lb/min. This makes me think your injector size is about 30% too small, aka your scalar has been multiplied by ~1.42.

Last edited by ShinjiML; 08-05-2016 at 09:46 AM.
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Old 08-20-2016, 06:28 PM   #6
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What Shinji said - it's a non-issue.

Basically you can make your g/s and g/rev numbers be whatever you want them to be, just by scaling your injector flow and MAF curve.

Also, if you want to simulate having a heaver car or taller gearing, just find a hill and drive up it. You'll find that the numbers don't change much, though.

"Load" in this case refers to the amount of air being "loaded" into the combustion chamber. That's roughly proportional to the load you place on the motor, but it's still not quite the same thing. You can make the load on the motor arbitrarily large by driving up an arbitrarily steep hill with an arbitrarily large trailer... but the amount of air being loaded into the combustion chamber will still be limited by your turbo, boost, air temps, etc.
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Old 08-20-2016, 07:17 PM   #7
no694terry
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Thanks guys. Its a carberry rom, not a DD anymore so its only been on e80 since installed and about 1k miles now. That log was from my map load axis rom, ive since switched it to g/rev load axis and now at the same boost and airflow (its full speed density) im only seeing like 3 g/rev so what ever, its just numbers, and was just curious.

And a side note, that log was also on dw850 side feeds, switched to denso mod 950s and way happier. Must have nailed my latencies this time. Warm up enrichment is a lot more consistant, no more B range surging

And ya, this turbo flows like ass, cant be the advertised 50 lbs. Feels sbout the same as my ported vf43. Gonna trade up for a BW 252sx-e. Soon as i can swing it

Last edited by no694terry; 08-20-2016 at 07:24 PM.
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