pop-up shock

[cheater35]

I was just wondering how much 50lbs of gas pressure to an integra pop-up shock would help forward bite? I currently have it at 150lbs and was wondering how much of a difference i would feel going up to 200lbs or even 250lbs. I'm struggling with forward bite a little on the slick and wanted to know everyones opinion before i start putting a ton of gas pressure to it.

Thanks,

[billetbirdcage]

Alot will depend on the valving of the pop up shock. The more gas pressure you add the more it will reduce the rebound and increase the compression. If the shock is a 0 then it will has negitive rebound once you get certain pressure (usually real early-like over 50# to 75#) then as you add more it will go more negitive. It is possible to get a #0 shock to read minus 4 or higher depending on the pressure, shaft size, if it has a resoviour, and ETC. If the shock has some rebound in it like a #2 then adding pressure will lessen the rebound more and may make it go to a negitive number. This just means with the pressure your running you may still have some rebound in it and adding more will take some more away or may it go negitive. So much depends on the shock and it rod pressure and the speed in which it is working in.

If the car is getting up all the way with 150# then adding pressure will only make it get up faster and stay up farther down the straight when other wise it might settle down. If the car is getting up fairly quickly and all the way adding pressure isn't going to make that big of change, it should be quite minor at that point except upon intial throttle and later on down the straight.

[cheater35]

Thanks, The car isn't getting up real well it could use more lift which will probably help forward bite.

[Rocket Bonehead]

Thanks, The car isn't getting up real well it could use more lift which will probably help forward bite.


I would look into your travel on the LR and see if you aren't bottoming out that LRF shock and limiting your travel. I know a few guys with Integra's that have been fighting this issue. A 1" or 2" extension solved the problem, as did removing it and/or switching brands. Integra's seem to have a very short extended length compared to other brands.



RB

[cheater35]

I have a 1" extension on it now i think i am going to try and put some more pressure to it and see what happens. you never learn if you don't try it right.

Also do you think the LRR shock would have anything to do with it not climbing the bars? I have the Ohlins LMJ's all the way around the car that i bought right from mastersbilt. The car is an "05" masters. I'm not sure even what valving they are i just bought them and go by the sheets that they gave me.

[Rocket Bonehead]

The LRF shock needs to measure 25.5" c-t-c in order to make sure you get the proper amount of travel. Yes, that is a Rocket measurement, but it holds true for the MB's I've delt with as well. Anything less doesn't allow the LR to get up.


To add to that, no, the Ohlins are NOT hurting you. In fact, I'd suggest getting the Ohlins LRF shock as it works well and that would match up your package. Also, as with a Rocket, you need a 2" extension for the LRR Ohlins shock on a MB. If you don't use the extension, you won't get the proper amount of travel.



RB

[cheater35]

AAAAAHHHHHHHHH,
I have a 1" extension on the LRF shock but have no extension on the LRR Ohlins maybe thats some of my problem. But when i put the floor jack in front of the LR tire in the shop and jack the frame up it looks like it gets plenty of travel or atleast alot more than what it is traveling on the race track.

Thanks for the help guys,

[talclipse]

Along these same lines how much of a difference is it going from an oil shock to a gas shock on the LRF shock?

[billetbirdcage]

Depending on the valving and the situation it can be huge or very little difference. I will say if I could only have one gas shock it would be on the LRF.

[cheater35]

How much difference is there in forward bite between a dummy shock and the gas pressure shock in front on the left rear? I should have said it is a 4compression 0rebound gas pressure Integra shock.

[billetbirdcage]

I can't tell you on an integra actual numbers but on an Afco shocks the difference would be something along these lines depending on the shock you have.

#1-- A older M1 Std gas montube shock that is a 5-0
#2-- A Std twin tube that is a 5-0

First of all a #0 at 4.7" per second has 16# to 18# pounds of resistance from seal and bearing drag. So the twin tube has 16 to 18# of rebound in it but is still considered a #0.

With that in mind (don't have the shock shart in front of me--so going off memory) a #1 is around 32#. So to me a #1 is really more like a #2 and a #0 is really a #1.

If you took that gas pressure shock and added 90 psi to it, the rebound would come out around -14# to -18# which is pushing up on the LR that mount at 4.7" per second as aposed to the twin tube having 16# of resistant slowing the LR from raising.

So with only 90 psi in the gas shock it is a full 32# to 36# less rebound then the twin tube (which a 0 to a 1 is 16 pounds) so that is like 2 numbers different in rebound.

When you get to the negitive numbers on rebound it is actually has rod pressure trying to lift the car instead of positive rebound restisting the car from lifting.

Also as you add gas pressure it also increases the compression which can act like a hydralic spring and loosen entry.

[cheater35]

Thanks billet i appreciate the help i'm not a shock man by any means.

I guess my question is will i notice a definite difference in forward bite going with the gas pressure shock at say 200 psi. vs. a Dummy shock with 0 valving. I'm just wondering if its worth the money or not. if it will help me with forward bite i'll definetely buy one, but if it isn't then i won't.
Thanks again guys. I'm just trying to learn something.

[bullittwrench]

We made the switch last year from a 6/1 twin tube to a 6/0 gas on the LRF and it was money well spent. Driver said after the first heat race that it felt like a totally different car. Makes a major difference on dry slick tracks. I run 150psi when it's tacky and 250psi in the slick.

[cheater35]

We made the switch last year from a 6/1 twin tube to a 6/0 gas on the LRF and it was money well spent. Driver said after the first heat race that it felt like a totally different car. Makes a major difference on dry slick tracks. I run 150psi when it's tacky and 250psi in the slick.

Thanks for the input i think i'll be giving it a try.