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post #1 of 38 Old 09-20-2018, 04:47 PM Thread Starter
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Second gear bog....

I've been noticing that when I launch at 3000 rpm; the car spins in first then bogs when I hit second. This is on an old back road with 315/17 drag radials at 28psi.
400rwhp 347
3.73 gears
Peak power is at 5800
Probably a 3500-3600 lb car with me in it.
I'm a complete amatuer curious as to why this happens.
Too much tire?


CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #2 of 38 Old 09-20-2018, 05:44 PM
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At what rpm does it hit 2nd gear at?


1989 Saleen 414 358cid SBF 2.8L Kenne Bell S/C
26 X 8.5 Hoosier
Best 1/4 mile time 8.623 @ 159.82 mph with a 1.34 60' (5.57 1/8th at 128)
Best 1/8 mile time 5.339 @ 133.46 mph with a 1.29 60'
08' Bullitt #4097 N/A 340ish RWHP <<<<<FOR SALE!
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post #3 of 38 Old 09-20-2018, 05:48 PM Thread Starter
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Originally Posted by Saleen414 View Post
At what rpm does it hit 2nd gear at?

I shift into second at around 6k.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #4 of 38 Old 09-20-2018, 07:50 PM
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And what is the rpm when it hits 2nd gear? It is not 6k rpm Lol.

1989 Saleen 414 358cid SBF 2.8L Kenne Bell S/C
26 X 8.5 Hoosier
Best 1/4 mile time 8.623 @ 159.82 mph with a 1.34 60' (5.57 1/8th at 128)
Best 1/8 mile time 5.339 @ 133.46 mph with a 1.29 60'
08' Bullitt #4097 N/A 340ish RWHP <<<<<FOR SALE!
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post #5 of 38 Old 09-20-2018, 08:44 PM Thread Starter
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Originally Posted by Saleen414 View Post
And what is the rpm when it hits 2nd gear? It is not 6k rpm Lol.
That's all the info I have until I drive it again. I knew what you meant. I'll datalog it.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #6 of 38 Old 09-20-2018, 09:58 PM
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What’s the engine combo? You sure it’s making 400rwhp?
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post #7 of 38 Old 09-20-2018, 10:08 PM Thread Starter
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Originally Posted by No Rice Nate View Post
What’s the engine combo? You sure it’s making 400rwhp?
Why do I always get asked that? Lol.
The car has been dyno'd countless times. Even on a 105į day it made 389rwhp on a Mustang dyno.
10:1 347
AFR 185 Renegades
Custom cam 230/238 @ .050
Systemax ll ported and matched by Ed Curtis
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.041" quench
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T5

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #8 of 38 Old 09-21-2018, 10:20 AM
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That bog is odd. I’m in the same neighborhood as you hp wise and my car usually spins a little when I shift second. Have you tried power shifting or spinning it higher in 1st?
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post #9 of 38 Old 09-21-2018, 12:14 PM Thread Starter
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Originally Posted by No Rice Nate View Post
That bog is odd. Iím in the same neighborhood as you hp wise and my car usually spins a little when I shift second. Have you tried power shifting or spinning it higher in 1st?
My son's Fox does the same thing now that he has installed drag radials. I think the hot roads in Phoenix really make the tires grab. Does that make sense? The rears do break loose on the 1-2 shift occasionally.
I'm pretty careful as far as high rpm launches due to having a T5. My rev limiter is set at 6200 and it happens quick with the 3.35 first gear.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #10 of 38 Old 09-25-2018, 06:03 PM Thread Starter
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Originally Posted by Saleen414 View Post
And what is the rpm when it hits 2nd gear? It is not 6k rpm Lol.
I finally logged this. It looks like I shift at nearly 6400 and rpm's drop to 2300 before climbing again. Being that my rev limiter is set to 6200; I'm overshooting that by a bit before shifting. I guess I need to readjust my shift light to trigger earlier. I'm not shifting like grandma either. I don't power shift due to having a T5.
Engine makes peak hp in the 5800-5900 range.


CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #11 of 38 Old 09-25-2018, 08:22 PM
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I am not buying what you are selling. There is no way you are dropping 4k rpm on a shift. It would be the widest ratio trans in the world. Lol. If an auto, then it is going from first to third on the shift....missing 2nd gear completely. It is the only reasonable explanation.

1989 Saleen 414 358cid SBF 2.8L Kenne Bell S/C
26 X 8.5 Hoosier
Best 1/4 mile time 8.623 @ 159.82 mph with a 1.34 60' (5.57 1/8th at 128)
Best 1/8 mile time 5.339 @ 133.46 mph with a 1.29 60'
08' Bullitt #4097 N/A 340ish RWHP <<<<<FOR SALE!
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post #12 of 38 Old 09-25-2018, 08:31 PM Thread Starter
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Originally Posted by Saleen414 View Post
I am not buying what you are selling. There is no way you are dropping 4k rpm on a shift. It would be the widest ratio trans in the world. Lol. If an auto, then it is going from first to third on the shift....missing 2nd gear completely. It is the only reasonable explanation.
No missed gears. I watched the rpm's on the datalog. It was just pointed out to me that the inj PW was cutting fuel.
I'm still in the tuning stage with forced open loop so who knows.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #13 of 38 Old 09-25-2018, 08:51 PM Thread Starter
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I'm having a hard time reading my logs in BE. It looks like I get back on the gas after the 1-2 shift at 4600ish. Sound better?

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #14 of 38 Old 09-25-2018, 09:37 PM
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Your problem is that it's still spinning when you shift to 2nd. Your engine may be spinning 6400, but since you don't have enough power to spin in 2nd, the tires hook after the shift and pulls rpm down to match actual ground speed. If the tires were hooked before the shift, 6400 would drop to around 3800 after the shift due to the ratio change from 3.35 to 1.99.

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post #15 of 38 Old 09-25-2018, 09:55 PM Thread Starter
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Your problem is that it's still spinning when you shift to 2nd. Your engine may be spinning 6400, but since you don't have enough power to spin in 2nd, the tires hook after the shift and pulls rpm down to match actual ground speed. If the tires were hooked before the shift, 6400 would drop to around 3800 after the shift due to the ratio change from 3.35 to 1.99.

Grant
Correct. Tires are spinning in first, but can't when I hit second. Being in Phoenix; there is no problem getting heat in the tires and they want to bite. A 315 tire has a big footprint which probably doesn't help.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #16 of 38 Old 09-26-2018, 03:06 AM
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What are trans ratios? What are you rev limited to? I almost see a 2800rpm drop from 1st to 2nd which almost drops me out of the peak power range causing a slight bog. Maybe this is the long version to what saleen is saying, but what I’ve learned to overcome is to shift as high as possible to keep the boost and peak power from dropping off so much.
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post #17 of 38 Old 09-26-2018, 03:15 AM
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I did a datalog recently to record rpm and wheel speed. A shift around 6500rpm put me in second gear at 3200, which when I overlayed that to my dyno graph, showed a significant drop in power. Only way for me to remedy is to shift at 7k.
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post #18 of 38 Old 09-26-2018, 01:23 PM Thread Starter
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What are trans ratios? What are you rev limited to? I almost see a 2800rpm drop from 1st to 2nd which almost drops me out of the peak power range causing a slight bog. Maybe this is the long version to what saleen is saying, but what Iíve learned to overcome is to shift as high as possible to keep the boost and peak power from dropping off so much.
See post #9.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #19 of 38 Old 09-26-2018, 01:29 PM Thread Starter
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Originally Posted by CrucialProspect View Post
I did a datalog recently to record rpm and wheel speed. A shift around 6500rpm put me in second gear at 3200, which when I overlayed that to my dyno graph, showed a significant drop in power. Only way for me to remedy is to shift at 7k.
I hear what you're saying. I just never thought I'd have to shift that high for an engine that makes peak power closer to 5800. I'm curious where you racers would shift for my combo. I realize the track and proper suspension changes a lot of variables.

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post #20 of 38 Old 09-26-2018, 03:15 PM
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Originally Posted by weenburner View Post
Your problem is that it's still spinning when you shift to 2nd. Your engine may be spinning 6400, but since you don't have enough power to spin in 2nd, the tires hook after the shift and pulls rpm down to match actual ground speed. If the tires were hooked before the shift, 6400 would drop to around 3800 after the shift due to the ratio change from 3.35 to 1.99.

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this...

easy way to fix this is to ride the clutch out more. keep the RPM up so to speak

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post #21 of 38 Old 09-26-2018, 04:02 PM
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Wow, I guess the page didn’t refresh and by the time it actually posted my reply, the questions have already been answered and suggestions already given! Sorry for beating a dead horse!
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post #22 of 38 Old 09-26-2018, 05:42 PM Thread Starter
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this...

easy way to fix this is to ride the clutch out more. keep the RPM up so to speak
Yeah; I have been dumping the clutch. I'm thinking about going to a more aggressive rear tire. Maybe M&H or Hoosier.
Maybe this way I will bite in first without spinning. I can't help but think that my current 315 tires would be too wide for my power, especially in a more aggressive tire.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #23 of 38 Old 09-26-2018, 05:43 PM Thread Starter
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Wow, I guess the page didnít refresh and by the time it actually posted my reply, the questions have already been answered and suggestions already given! Sorry for beating a dead horse!
Lol! No problem. Keep the suggestions coming.

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post #24 of 38 Old 09-27-2018, 12:01 AM
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Why are u launching at 3000 with tire spin?

Why are u reving at 6000 rpm while the tire are spinning?

What do u expect spinning the tire and shifting into second. U are dragging the engine down when the tire stops while u press the clutch u do not even have enough road speed that is why it dropping such a hi rpm loss.


The object is not to spin the tire either walk out the clutch or peddle it. Or shift when the tire starts to spins. Learn how to drive the car.
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post #25 of 38 Old 09-27-2018, 03:24 AM
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Going back to your first thread, your using a 315 drag radial at 28psi, I ran a drag radial for 1 season without much luck, and I was running much lower tire pressure. I believe I was running a 275 Mickey Thompson et streets with 18psi. I switched to a Hoosier qtp at 14psi and had much better luck since then.

I’m sure someone else may be able to point you in the right direction better than me, but it was an uphill battle for me trying to get drag radials to hook. Without being an expert in the subject, is 28psi a little high?
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post #26 of 38 Old 09-27-2018, 06:36 AM
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Without being an expert in the subject, is 28psi a little high?
honestly not really... we have been 1.10 on 18lbs in them with about 2k more horsepower.

without seeing video to see what exactly the car is doing and how its sounds like hes just being overly aggressive with the clutch. a radial you want to stick the tire hard to get the tire to dig in and make the suspension work (most people have no clue how to make a radial work correctly) then apply power smooth and quick not to upset the car.

its a balancing act on how hard you need to shock it at the hit and then how fast you bring it in. best way ive heard it put is balancing a BB on a razor blade
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post #27 of 38 Old 09-27-2018, 12:35 PM Thread Starter
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Originally Posted by Blown and strocked View Post
Why are u launching at 3000 with tire spin?

Why are u reving at 6000 rpm while the tire are spinning?

What do u expect spinning the tire and shifting into second. U are dragging the engine down when the tire stops while u press the clutch u do not even have enough road speed that is why it dropping such a hi rpm loss.


The object is not to spin the tire either walk out the clutch or peddle it. Or shift when the tire starts to spins. Learn how to drive the car.
Whoa there! I have never drag raced a car, thus my questions. What may be second nature to you is all new to me. The car was a different animal when I had street tires on it. I'm now adjusting to the drag radials.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #28 of 38 Old 09-27-2018, 12:38 PM Thread Starter
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Originally Posted by CrucialProspect View Post
Going back to your first thread, your using a 315 drag radial at 28psi, I ran a drag radial for 1 season without much luck, and I was running much lower tire pressure. I believe I was running a 275 Mickey Thompson et streets with 18psi. I switched to a Hoosier qtp at 14psi and had much better luck since then.

Iím sure someone else may be able to point you in the right direction better than me, but it was an uphill battle for me trying to get drag radials to hook. Without being an expert in the subject, is 28psi a little high?
Keep in mind that this isn't occurring at the track. I'm just an old duff playing on a back road. If I were to go to the track; Nitto recommends around 18psi.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #29 of 38 Old 09-27-2018, 12:43 PM Thread Starter
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honestly not really... we have been 1.10 on 18lbs in them with about 2k more horsepower.

without seeing video to see what exactly the car is doing and how its sounds like hes just being overly aggressive with the clutch. a radial you want to stick the tire hard to get the tire to dig in and make the suspension work (most people have no clue how to make a radial work correctly) then apply power smooth and quick not to upset the car.

its a balancing act on how hard you need to shock it at the hit and then how fast you bring it in. best way ive heard it put is balancing a BB on a razor blade
Thanks for the analogy. I'll play with launch rpm and see what happens. I think the cautious side of me is saying "don't slip the clutch." I've thought about using a Clutch Tamer.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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Thanks for the analogy. I'll play with launch rpm and see what happens. I think the cautious side of me is saying "don't slip the clutch." I've thought about using a Clutch Tamer.
If you have the wallet to handle it id call Tinzy at black magic and let them work their ... well black magic

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post #31 of 38 Old 09-28-2018, 08:48 PM
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1989 Saleen 414 358cid SBF 2.8L Kenne Bell S/C
26 X 8.5 Hoosier
Best 1/4 mile time 8.623 @ 159.82 mph with a 1.34 60' (5.57 1/8th at 128)
Best 1/8 mile time 5.339 @ 133.46 mph with a 1.29 60'
08' Bullitt #4097 N/A 340ish RWHP <<<<<FOR SALE!
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post #32 of 38 Old 09-29-2018, 02:18 PM
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Time for some home work. You need to find out what your first gear ratio is and 2nd. Next find a racing calculator or do the math your self. I also find that the bog rpm is low and probably do to tire spin and a wide ratio 1st to 2nd t5. You wonder why people ask your dyno numbers? They are for sea level and corrected for your altitude and baro. You may only make 400 at the corrected numbers and 350 at the present conditions.

After you figure this out try launching at the rpm in 1st to where the drop in 2nd is at peak torque rpm. This is why one need your dyno numbers. You may need to launch 2 to 5 hundred rpm higher then this as a rule of thumb. By the way if you spin to much you need to work on your suspension.
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post #33 of 38 Old 09-29-2018, 03:26 PM Thread Starter
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Time for some home work. You need to find out what your first gear ratio is and 2nd. Next find a racing calculator or do the math your self. I also find that the bog rpm is low and probably do to tire spin and a wide ratio 1st to 2nd t5. You wonder why people ask your dyno numbers? They are for sea level and corrected for your altitude and baro. You may only make 400 at the corrected numbers and 350 at the present conditions.

After you figure this out try launching at the rpm in 1st to where the drop in 2nd is at peak torque rpm. This is why one need your dyno numbers. You may need to launch 2 to 5 hundred rpm higher then this as a rule of thumb. By the way if you spin to much you need to work on your suspension.
It's a stock T5 for now. It's just went out and tried a few launches. I wasn't too scientific about it but wanted to get a feel for slipping the clutch at launch. First gear spun even easier and gained some wheel speed. The car liked that and it even spun a tad in second with no bog. I realize that spinning is not what I want, but it was interesting to see the difference.

I definitely need to change all of my suspension. The car is currently set up for handling with H&R Race coils and Bilsteins. I'll be copying my son's setup with Strange coilovers up front and stange shocks in the rear. Strange struts and shocks are ten ways. I may steal my son's stock '86 GT rear coils. I want the car lowered a bit, so I'd cut one coil out of the rear springs. I have nice upper and lower arms unless I need weight jackers in the rear.

I'm reviewing my datalogs in a minute.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
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post #34 of 38 Old 09-29-2018, 04:08 PM
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Sounds like u are learning. Good. Unless u are racing it at a track or on the street I would leave the suspension alone. Unless u want to drop the ride height. It is nice having a car that can handle turns.

Gotta figure out what rpm between bog and spin while slipping out the clutch. During launch. Learning process.

At the track do a second gear burn out after the water box set tire pressure to 16 to 18 psi. The tire pressure help with the hook up while maintaining hi speed stability . Find the happy medium.

Remember easier to spin second with street set up then drag set up.

You are doing good.
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Sounds like u are learning. Good. Unless u are racing it at a track or on the street I would leave the suspension alone. Unless u want to drop the ride height. It is nice having a car that can handle turns.

Gotta figure out what rpm between bog and spin while slipping out the clutch. During launch. Learning process.

At the track do a second gear burn out after the water box set tire pressure to 16 to 18 psi. The tire pressure help with the hook up while maintaining hi speed stability . Find the happy medium.

Remember easier to spin second with street set up then drag set up.

You are doing good.
Thanks. The car handles like a go-cart with the current suspension although it could use a panhard bar. The negative side of that is a very sporty ride. IRS is better suited for handling in my opinion after playing with my '18 Ecoboost. I plan on hitting the strip this fall/winter so until then; I'm not fully committed.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
Buyer Beware.
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