New PB 10.28 @ 134

[JUIC3D]

jack it all you want:uh oh:

Lol

Car is going 1.48-1.52 60ft on the 100 shot. It went 1.60-1.63 on motor with LESS suspension work. Now, it has a lot of suspension work to be going "shitty" 60 ft times imo. I damn near have the entire BMR catalog under my car and the car isn't performing to the level I think it should. My kit isn't flowing correctly so right now I'm jetted at 100hp and the car is ET/MPH'ing ok but I think it should/could be better.

 

[BMR Tech]

^ #becausemanualtrans.

Maybe I can catch some time to go with you (without my car) to the track, and we can tune/dial it in.

Is your nitrous activating right at the hit, or is there any delay?

You may want to look into going much more, or much less AS% to see if that is the primary factor. I like to see a car hook due to AS%.....then dial in/fine tune it with the dampers.

Have you tried to use multiple mounting positions on the LCA Brackets yet? Also, have you tried lowering the RPM to the bogging point, then raise very small increments?

I've never been a big fan of high RPM manual transmission nitrous launches. I am more if a lower RPM, let the TQ (more at lower RPM) pull the car out of the hole - kinda guy. I dont even like 2 steps with nitrous, personally.

 

[JUIC3D]

^ #becausemanualtrans.

Maybe I can catch some time to go with you (without my car) to the track, and we can tune/dial it in.

Is your nitrous activating right at the hit, or is there any delay?

You may want to look into going much more, or much less AS% to see if that is the primary factor. I like to see a car hook due to AS%.....then dial in/fine tune it with the dampers.

Have you tried to use multiple mounting positions on the LCA Brackets yet? Also, have you tried lowering the RPM to the bogging point, then raise very small increments?

I haven't touched uca/lca locations. UCA is at top hole, LCA relos are on middle hole. Nitrous activates at WOT(same as yours) with no delay. I have some pretty good video I can show you that shows exactly what suspension is doing. On the 1.48s, it weight transfers, front end rises, tires spin a little bit, and the car starts to separate and go. It's not a bad launch or anything, I just think it can be better. It might not have enough power to go any faster though--thats what I'm not sure of..

I can't run the risk of bogging on a nitrous hit since I don't run a window switch. If it bogs and the kit is spraying, bye bye motor.

 

[JUIC3D]

I've never been a big fan of high RPM manual transmission nitrous launches. I am more if a lower RPM, let the TQ (more at lower RPM) pull the car out of the hole - kinda guy. I dont even like 2 steps with nitrous, personally.

The 2 step keeps launch rpm consistent. I can't slip the clutch without the computer closing the throttle blade so it's all or nothing.

I prefer a lower rpm launch as well and the car is going the 1.48s with the 4700rpm launch.

 

[BMR Tech]

I gotcha - I understand completely, as far as the nitrous goes. I dont blame ya, either.

That is what will be tricky, though. We need to find out where the car bogs. With a manual nitrous car, you will typically get your best traction/sixty foot by stepping up right above the point of bogging. This will give you the best combination of TQ and traction.

It's odd how your car works. The actual car itself looks "PERFECT" when you launch, but the wheel speed is just a little too much.

Just to see......put your LCA in the bottom hole of the brackets and see what happens. If it spins more on the initial hit, then we know you are hitting the tires too hard. In that case, raising to the top position may be the ticket.

 

[BMR Tech]

Well, we need to do two things. (one or the other)

Lower the RPM a little - or change LCA positions.

Would you feel comfortable with the 2-step at 3500-3800?

 

[JUIC3D]

I gotcha - I understand completely, as far as the nitrous goes. I dont blame ya, either.

That is what will be tricky, though. We need to find out where the car bogs. With a manual nitrous car, you will typically get your best traction/sixty foot by stepping up right above the point of bogging. This will give you the best combination of TQ and traction.

It's odd how your car works. The actual car itself looks "PERFECT" when you launch, but the wheel speed is just a little too much.

Just to see......put your LCA in the bottom hole of the brackets and see what happens. If it spins more on the initial hit, then we know you are hitting the tires too hard. In that case, raising to the top position may be the ticket.

I can do that. I bet you'll really like the video I'll post later tonight as far as the launch is concerned. It looks damn near perfect with just a hair too much wheel speed. I launched at 4700 and it spun-hooked and just slingshot out to the 1.48 60'.

I wonder if, because I swapped out from sportlines to bmr springs, and the car is raised up more in the rear, if the middle hole is just a bit too much leverage on the tires. Maybe the upper hole will in fact work better. idk. I guess there's really only one way to find out.

 

[JUIC3D]

Well, we need to do two things. (one or the other)

Lower the RPM a little - or change LCA positions.

Would you feel comfortable with the 2-step at 3500-3800?

Na, I won't go much below it's current setting. If it hooks and bogs from a 3800rpm launch, that won't end well.

I'll try the lca setting first.

 

[BMR Tech]

Gotcha.

Well, let's get that done and go from there sir!

If you raise the LCA, you will want to run around 4C / 8R

If you lower the LCA, you will want to run around 8C / 5R

 

[JUIC3D]

I'll see if I can get out of work on time thursday to go visit the track again..

Raising the control arm angle(decreasing leverage) means you want softer shocks? I would have though it was the other way around. Right now my 1.4s come with 2 on the fronts, and 6/8 or 6/10 on the rears.


Learn me something please

 

[Fabbed5.0]

Since were already off track from Ryan post lol ill post Justin slo mo here. Kelly wouldn't you want to lower the control arms in the bottom hold to reduce tire speed??

<iframe width="560" height="315" src="//www.youtube.com/embed/KnZf1QNYtOQ" frameborder="0" allowfullscreen></iframe>

 

[Shiken_Feddas]

Holy baby mama that wheel spin!

 

[JUIC3D]

Hm, what pass was that Jim? Scoreboards were off so it's hard to know. I don't even know if I was spraying there or not. I think that was a 1.55 60' since thats the only time I raced Alan in his vette

 

[BMR Tech]

Lowering the LCA (steeper angle / more AS%) will cause the back of the car to separate more from the axle.

Raising (lessening the AS%) the LCA, will cause the car to want to squat more.

When a car raises, you want to allow it to raise....so the suspension is "working" at applying force to the tire. Since it raises, it has to come down. If it comes down to quickly (compression) - it will unload the tires. So you stiffen the compression up, compared to the rebound (extension).

When a car squats....it is not hitting the tires with as much force. Sometimes this is good, because you are relying less on the sidewall of the tire....and more so on track prep and suspension, to maintain/achieve traction. When the car squats, it has toc ome back up. Coming back up to quickly can/will enable tires to unload. In this case, you want to allow the car to squat (strategically) - then control the movement back up.....therefore, the rebound needs to typically be stiffer than the compression. In a squatting car....too much compression can cause the tires to spin due to hitting them too hard.

It's a balance that you have to figure out, and it can take some time.

If you notice the Viking Shock instructions, they likely tell you that for drag race you want like a 2C / 7R or something along those lines. This is because most cars squat. Most cars at the strip dont have all the cool goodies you guys do, to adjust your AS% so easily. A fox body for example....lower it, put slicks on it, and it will squat like crazy.

Also remember, more times than not....softer shock/strut settings leads to better weight transder of the body of the car. You have to be careful though, too much transfer is what you see people call "wasted energy". The stiffest settings that work, are going to be the best....but sometimes, you have to loosen things up a bit to get some better transfer, and make the sidewall of the tire less responsible for traction.

I could talk for days about this stuff....

 

[JUIC3D]

I could listen for days about this stuff..

continue..

 

[JUIC3D]

So if it's squatting too hard (like in that video) I need to stiffen up the compression which should in keep the body separated which drives the tires into the ground which equals more traction? Did I get that correctly?

 

[BMR Tech]

Kelly wouldn't you want to lower the control arms in the bottom hold to reduce tire speed??

It depends.

Too much anti-squat can cause immediate tire spin.

After watching that video, I am not convinced Justin has too much AS%.

That said, he has all the good parts....so it is worth trying, to see what happens.

I just saw the post of 6/8 and 6/10 on the rears. Since your car is not squatting, nor raising much at all.....I would lean more towards balancing them out and seeing what happens. Like, 5-6C/4-5R.....or something close to that. I dont see the need for 10 on Rebound, as the car is not squatting. You want that stiff rebound for a squatting car, to control the rise.

Remember, a car that doesn't squat or raise drastically, is a faster/quicker car if you hook. A car that doesn't squat or raise drastically, can typically work well on softer shock settings.

 

[BMR Tech]

So if it's squatting too hard (like in that video) I need to stiffen up the compression which should in keep the body separated which drives the tires into the ground which equals more traction? Did I get that correctly?

To an extent, yes.

But....remember, that squat in the video isnt from your geometry.....it is from the lack of an ARB. If you watched the other side, it didnt squat at all, I bet. ;-)

 

[JUIC3D]

Let me post the video tonight of my 1.48 60' and have you critique it. It's still annihilating the tires, but it does so to the tune of a 1.48 so idk--it's bad but good at the same time.

I believe I had them set at 6/8/2(up front), with 14psi hot in the tires and a 4700 2 step.

 

[JUIC3D]

To an extent, yes.

But....remember, that squat in the video isnt from your geometry.....it is from the lack of an ARB. If you watched the other side, it didnt squat at all, I bet. ;-)

Good point. The video I'll post tonight has the driver's side angle and I think it looks pretty good as far as how the suspension appears to be working--the tires just spin...