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View Full Version : Freeing Up Middle On Throttle?



HuckleberryB4
08-10-2011, 10:30 AM
I'm looking for some ideas on freeing up my car in the middle and having the most minimal adverse change somewhere else. The car is good getting in and down the shoots once it's straight, but picks up a very slight throttle push in the middle that I wan't to get rid of. I'd prefer not take any LR bite out of the car because I'm pleased with the forward bite I'm getting. The car is really close and I have a few ideas myself, but would like to pick your brains aswell. Thanks.

rubbinsracin
08-10-2011, 10:57 AM
maybe add some rebound to the LF shock, or you could maybe move your 5th coil out a hole or so.

dualdj1
08-10-2011, 01:29 PM
x2 on lf rebound.

grt74
08-10-2011, 02:19 PM
Stagger??rf rebound tie it down more??rr bars a little longer??it sounds like your close so it wont take much i would try one thing at a time but it sounds like you already know that,J BAR BUT THAT WILL PROBABLY BE TO MUCH

HuckleberryB4
08-10-2011, 05:10 PM
I believe that I'm maxed out on rebound for the LF. And I already have a tiedown shock on the RF. The options that I had in mind were to add some stagger, since I usually only run no more than 1/4" or to lengthen the right side bars 1/2" so that I have more left side lead. But I'm afraid that if I lead the LR it could cause the car to loosen up getting in too. So I'm not sure if the trade off would be beneficial for me at exit or hurt me more on entry?

Len72P
08-10-2011, 08:05 PM
Left lower bar down on frame to level. Should remove instant bite when gasing up.

Matt49
08-11-2011, 08:30 AM
Well...I have to disagree with two previous posts.
You should raise (not lower) the left lower bar up on the frame. This will make the birdcage index slower which will generate less "instant" drive and should take away your throttle push. It will also create a little more roll steer which will get you rotated better in the center.
Moving the 5th coil out typically lifts the front of the car more on initial throttle which takes grip away from the front tires so I would move it back to fix an initial throttle push issue...HOWEVER this will give you more instant forward bite which if the indexing is the problem could make your situation worse.
The driver has to be able to feel what is happening to figure out what the car needs.
When it pushes on the throttle does it feel like the front end just picks up and moves over to the right? - if so, move 5th coil back.
- or -
When it pushes on the throttle does it feel like somebody is pushing/ramming the car from the LR quarter panel (too much "drive" in the left rear)? - if so, raise LR bottom bar up on frame.
Other thoughts: A lot of people say they have a "throttle push" when really the car is just too tight in the center of the corner. It just so happens that is when they are trying to pick up the throttle. Not saying this is the case with you but if you're not sure, just try rolling through that portion of the corner without applying as much throttle. If the car is still tight, you've got too much side bite and you might want to look elsewhere to free the car up. Like taking some j-bar angle out, decreasing left side weight, lowering ballast, etc.

rubbinsracin
08-11-2011, 09:07 AM
Moving the 5th coil out typically lifts the front of the car more on initial throttle which takes grip away from the front tires so I would move it back to fix an initial throttle push issue...HOWEVER this will give you more instant forward bite which if the indexing is the problem could make your situation worse.
The driver has to be able to feel what is happening to figure out what the car needs.
When it pushes on the throttle does it feel like the front end just picks up and moves over to the right? - if so, move 5th coil back.


This is exactly opposite of what i have experienced. when we moved it forward we kept the front tires on the ground better. when we moved it backwards, is when we really started to 3wheel around the track. not saying you're wrong, could have been our the rest of our setup combined with moving it back that caused the 3 wheeling.

HuckleberryB4
08-11-2011, 10:33 AM
The push is coming from the LR getting too much drive. I know I could take turns out, but once it's straight it gets great bite, so I didn't want to go that route. I just need to free it up a little more when I start to roll on the throttle. I'll try moving the LR bottom bar up a hole. If it still feels like it's wanting to nose up the track, I'll look at lowering the J-bar next. Thanks.

Matt49
08-11-2011, 11:44 AM
This is exactly opposite of what i have experienced. when we moved it forward we kept the front tires on the ground better. when we moved it backwards, is when we really started to 3wheel around the track. not saying you're wrong, could have been our the rest of our setup combined with moving it back that caused the 3 wheeling.

Interesting. Maybe 5th coil spring rate is causing us to have experienced different things. We tend to run a softer 5th coil spring than most.

rubbinsracin
08-11-2011, 12:24 PM
we run a 300. what by chance do you run? when we bought the car it had a 175 in it. but it was way to soft for us.

MasterSbilt_Racer
08-11-2011, 12:56 PM
This is exactly opposite of what i have experienced. when we moved it forward we kept the front tires on the ground better. when we moved it backwards, is when we really started to 3wheel around the track. not saying you're wrong, could have been our the rest of our setup combined with moving it back that caused the 3 wheeling.

That is possible because if you get it back it can start helping the car bar up on the lr and even the rr too if the rebound of the rr is soft, etc. The lr gaining angle that it didn't get before can make the lf raise up.

Generally, I agree that moving it forward should make the front of the car "lighter" on the gas.

Matt49
08-11-2011, 04:37 PM
we run a 300. what by chance do you run? when we bought the car it had a 175 in it. but it was way to soft for us.

We run a 350 which is lighter than the 400 that our car calls for. I like the feel of it a little softer (our tracks get glass/black slick) and I run it back further than most - that's all I'll say for now on that :-)

We're going to do some things significantly different next season with 5th coil stuff.

4bangerhotrod
08-11-2011, 11:38 PM
moving the 5th coil out, say from 34in to 36in has to lighten the front of the car more than it would be if it was at 34in just cause the point that the 5th coil is pushing up on the car is farther forward. but there is alot of factors with spring rate in the car to how the car reacts and the feel the driver gets. i think alot of drivers problems is trying to run to stiff of a 5th coil spring. its all depending on driving style to what works but i think about a 325lb spring is the stiffest that would ever need to be run. personally the cars i work on havnt been over a 300 in the last 6-7yrs and its not often that we go that stiff. most people would be amazed at what a 250lb spring will do to a car, personally i perfer a 275lb spring. to me the stiffer spring seems to upset the car to much, it makes the car react to quick most people like this feel because it makes them feel like there getting all kinds of instant bite but its upsetting the tires grip on the track. anytime a car can react in a smooth motion its going to keep the tires planted better and not upset the car it feels slower but makes the car much more consistant and lets the car carry more momentem. about 4 yrs ago the car i was setting up won a very large race which the driver was prob the dark horse to win, over the next few days about 10 people asked me what 5th coil spring i was running and no one believed me when i told them 225lb spring untill i would show them cause everyone was saying run a 350-400lb springs. i have tried this on 4 different chassis brands and the drivers perfered the lighter spring in each chassis once they got the feel for it an learned to drive smoother.
thanks,
4bangerhotrod

MasterSbilt_Racer
08-12-2011, 02:51 PM
moving the 5th coil out, say from 34in to 36in has to lighten the front of the car more than it would be if it was at 34in just cause the point that the 5th coil is pushing up on the car is farther forward. but there is alot of factors with spring rate in the car to how the car reacts and the feel the driver gets. i think alot of drivers problems is trying to run to stiff of a 5th coil spring. its all depending on driving style to what works but i think about a 325lb spring is the stiffest that would ever need to be run. personally the cars i work on havnt been over a 300 in the last 6-7yrs and its not often that we go that stiff. most people would be amazed at what a 250lb spring will do to a car, personally i perfer a 275lb spring. to me the stiffer spring seems to upset the car to much, it makes the car react to quick most people like this feel because it makes them feel like there getting all kinds of instant bite but its upsetting the tires grip on the track. anytime a car can react in a smooth motion its going to keep the tires planted better and not upset the car it feels slower but makes the car much more consistant and lets the car carry more momentem. about 4 yrs ago the car i was setting up won a very large race which the driver was prob the dark horse to win, over the next few days about 10 people asked me what 5th coil spring i was running and no one believed me when i told them 225lb spring untill i would show them cause everyone was saying run a 350-400lb springs. i have tried this on 4 different chassis brands and the drivers perfered the lighter spring in each chassis once they got the feel for it an learned to drive smoother.
thanks,
4bangerhotrod

Like you say, to each his own. My experience has been almost the opposite. I have increased the speed of my own car and others from getting lapped to running top 5 by only changing the 5th coil rate.

racinground
08-23-2011, 03:12 PM
Try more rebound in the right front shock. Should hold the car off the left rear just a little longer might be just engough to make it through the corner without it pushing.
I've found that if the car has a little push it is actually faster as long as you can come off straight.

leadorfollow
08-24-2011, 09:31 PM
one other alternative we have done is to either put more gas pressure in the lrf shock which wants to do the same as put more rebound in the rf and keeps it tied down more. Also you could simply put a couple turns in the lf to get it further over on the rf. The pressure in the lrf shock will also add forward drive but it may hurt you on entrance. Just something to try if you have practice nights at your track.

tomuchbite
08-28-2011, 07:56 PM
Raising the top right 4bar is a suttle change that will help from the center out!



I'm looking for some ideas on freeing up my car in the middle and having the most minimal adverse change somewhere else. The car is good getting in and down the shoots once it's straight, but picks up a very slight throttle push in the middle that I wan't to get rid of. I'd prefer not take any LR bite out of the car because I'm pleased with the forward bite I'm getting. The car is really close and I have a few ideas myself, but would like to pick your brains aswell. Thanks.

hpmaster
08-28-2011, 08:17 PM
move a full hole up on the left lower on the frame or lengthen the right side bars a 1/4" that seems like about half the effect of a full hole up on the left lower and does not seem to upset the car in other places. Use some bite to plant right front. Thats what we did with our car Friday to free it up and get it to rotate. I have found the left lower placement on the frame and right side bar length can dial the center out if you don't over adjust it.

hpmaster
08-28-2011, 08:21 PM
oh also added 1/4" more, 1/2" total preload on 5th coil, it's a AFCO progressive.

GRTLRBITE
08-29-2011, 04:59 PM
raise right upper bar or take rebound out of rr