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Looking for more RPMs

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KartingIMG

Member
Looking for some tips to generate more RPMs on a predator 212 hemi. For some reason we are only turning about 4900rpms on a 1/8 mile track and it’s like we are standing still to other racers. Any help would be greatly appreciated!

Thanks!
KartingIMG
 
alvin l nunley said:
What are the tech procedures at your track? It's a stock motor class right, how far off could you be?
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I’m unsure what the tech procedures are. They only tech the top 3. Just ran a 2 day event there and from talking to guys around my pit stall they are running 5200+ Just wondering what I’m doing to not get there. Running a 2008 phantom Icon
 
KartingIMG said:
Removal of oil sensor governor removal that’s it. Running 16/62 gearing.
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If indeed it is a 1/8 mile and makes good momentum with any grip at all with a 16/62 that gearing would be off, example our small 1/8 but momentum good grip gearing to get 4900 rpm is 17/58, do you know what gearing someone fast in your class is using ?
 
You need to find out who's doing the engine and take it too that person .
Otherwise replace the valve springs .
 
KartingIMG said:
I’m unsure what the tech procedures are. They only tech the top 3. Just ran a 2 day event there and from talking to guys around my pit stall they are running 5200+ Just wondering what I’m doing to not get there. Running a 2008 phantom Icon
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If your not gear bound now adding 3 teeth to the rear would get you to 5200 unless tires are way off, but I doubt that's your answer.
 
racing promotor said:
If indeed it is a 1/8 mile and makes good momentum with any grip at all with a 16/62 that gearing would be off, example our small 1/8 but momentum good grip gearing to get 4900 rpm is 17/58, do you know what gearing someone fast in your class is using ?
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I can’t seem to get an answer out of anybody about what gear ratio they’re running. If I’m running wrong gear 16/62, and going to 17/58 my right wheel diameter is 11.5, we have to run Hoosier tires Is that going to make a differencis that going to make a difference? Am I running wrong tire size?
 
First are you on Treads ? Yes tire size will affect gear .
You gotta try something . RP has good gear advice . You won't do any worse .
 
KartingIMG said:
I can’t seem to get an answer out of anybody about what gear ratio they’re running. If I’m running wrong gear 16/62, and going to 17/58 my right wheel diameter is 11.5, we have to run Hoosier tires Is that going to make a differencis that going to make a difference? Am I running wrong tire size?
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Yes tire size would make a difference in my example, but your getting what your getting with the 16/62 with that size SO first I would leave the 16 driver on but drop rear to a 58 see what it does to prove your not gear bound, If you do that and RPMs stay close same or same your gear bound keep dropping, If you loose 300 rpm min you'll need to try a 16/65 for 5200 rpm, but again I doubt that's your answer.
 
racing promotor said:
Yes tire size would make a difference in my example, but your getting what your getting with the 16/62 with that size SO first I would leave the 16 driver on but drop rear to a 58 see what it does to prove your not gear bound, If you do that and RPMs stay close same or same your gear bound keep dropping, If you loose 300 rpm min you'll need to try a 16/65 for 5200 rpm, but again I doubt that's your answer.
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I did run a 16/64 on Saturday and it didn’t seem to change anything. I think I might jump down to a 16/57ish with 4900 rpms and see what Happens. Trial and error.
 
Here's a gear ratio chart for you. What I would recommend is; add one tooth to the axle, if you pick up about 100 RPM, at another tooth, same thing again. If you add one tooth and don't pick up 100 RPM, gear ratio is not your problem. HP is your problem.
If it is that, lack of horse power, you're going to need to spend some money. My favorite 60-year-old saying is "speed costs, how fast do you want to go".

Pay someone else, money, do-it-yourself, less money.

Ignition timing, very important. Buy a degree wheel. Learn how to use it. Find out what the rules are on timing.

Find out what the rules are on mixture ratios. Very important.

Spark plugs. What are the rules. This is a start, let us know what you find.
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the videos I saw on youtube it makes pretty good momentum. I don’t think I’d be afraid to try a 17 driver there at all
 
I will add this don’t chase an RPM number... mine has been doing great this year and won’t free rev on a stand past 5000 it hits a wall and sounds like it’s gonna detonate..
 
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