soft loc or advanced launch question

[Jeff Lee]

Most definetly pulls the engine WAY down on launch. The fact your laying rubber on the gear changes should tell you something...
I have no experience with a 4-link. Maybe somebody will want to chime in on that issue seperately. But it doesn't look like it's right either...My guess is the IC is to short?

[L79racer]

I/C is about 44" Tires were set at 12.5 lbs cold so, after the burnout they were problably at about 15 lbs. Shifting at 7200 got a little spin as apposed to the 4000 launch which spun a little before the engine pulled down. I think I was leaving at too low of a rpm. I'm thinking I should try a 6000 launch with the 28x11.5 slicks at 10 lbs and see what happens.

[Joe Sprint Bros]

L79, I think you would going in the right direction to leave higher and less air (9.5-10.5 lbs). I would also pull over to side at end of track(return road) and measure each tire immediately.If they are different psi (assuming same at starting line) then you need to look at chassis preload, tire circumference,etc. Are you using the Alum wheel and 900 series disc? Joe.

[L79racer]

Joe, so if the tire pressure is different at the end of the track the preload is not right and heating the tires unequally?? Am I understanding that correctly? Yes, I am using Rams aluminum flywheel and a 900 series disc. I did speak to Rob at advanced and he said he could change my springs, add the counter weigh levers and give me a new disc and chance the heat shields on the flywheel. The clutch I have is an 11" and Rob said it was way too big for what I need. At the most a 10". He recommends going to a 7". Vinny

[LNorton]

I talked with Rob about a clutch for our V6 car a while back. He is pretty keen about going to as small a disc as you can. He was thinking a 6'' unit for us. But when I told him I would put close to 400 runs on it in a year if I got to race as much as we can in these parts, he said to go with a 9'' for mileage.

After talking with him a few times, I can say that Rob is pretty slick.

Just cant afford it for now...

[Joe Sprint Bros]

L79, that's right, tires should be same +or-1/4lbs. If they are 2-3 lbs higher then you are hazing them long ways down track.I think they should only increase 3/4-1 1/2 bls once the cae is working properly. Measured circumference at starting line pressure should not be more than 1/4-3/8" on short tire. If you need new tires, make sure buy matched pair. From the video it looks like it is spinning most of the 330, and I think some of that is chassis. If the idea is to make the car launch better on a budget, I think I would be trying different bar settings, shock settings, maybe loosen the front some, since that doesn't cost much money.Adjustable shocks would allow you to tighten up for street use. Sometimes weight in the right place makes a car quicker and more consistent on the launch. Maybe retard 1st gear with microswitch on shifter? I sucessfully ran the same clutch you have(with some mods) before moving on to ADV. Since you already own this clutch, use it up while you sort out chassis, the maintenance on any of the centrif clutches is more intense and expensive. Then go buy ADV when you have the money. Joe.

[Jeff Lee]

L79 -
Clarify your intent with this car. We know it is a street / strip car. Dual useage can be more demanding than single useage. By more demanding, I'm saying what Joe is saying; suspension and / or chassis along with clutch adjustments before and after racing on the track will be necessary (not suggested, necessary; especially with clutch adjusting). Since it appears your using the slicks around town, if your looking to obtain optimum ET at the track, you'll probably need track slicks as well.
So the question is, what are you willing to do? My gutt feeling is your looking for that 9 second street car ET without having to do all the other stuff that would compromise the street duty aspect and making changes at the track. If that's the case, I would suggest adding nitrous or a bigger engine. That way you'll have 9's although the relationship between MPH and optimum ET will always be sacraficed. If you are definite on not making clutch adjustments for your dual purpose vehicle then I would suggest an automatic transmission.

[L79racer]

Joe, I have 3 way adjustable shocks in the front. I have them set tight because I thought it would put more leverage to the rear tires.(from baseline suspensions info). I do have two sets of slicks for it. Car is really set for racing and not a cruiser. I drive it to where we race on the street and hang out. I dont think the 4 link is far off from a good setting. I went by what the guys at Chris Alston recommended. I think I will lower the air pressure and launch it at 6000 to see how it reacts. If it doesnt work properly I'll go into the 4 link a bit and get the lighter springs for the plate. Eventually I'll got with a fully adjustable clutch from Rob.

Jeff, I do want to crack the 9's because I see the mph and know what the potential et is. If I didnt have the mph I wouldnt care about going that fast. I dont want a 9 second car just to say I go 9's so, nitrous is out. I pride myself for having a fast streetable pump gas small block though. As for the automatic. All my friends who run automatics are constantly telling me to put one in. I've been runing stick cars since I'm18 and wont give in. I just love pulling and pushing that shifter. Someday I'de like to try one of those Tex racing clutchless trannies or a jerico.

Thanks to all that responded and If anybody has anything to add please feel free to. Thanks again in advance.

[69Cobra]

L79,
Check out our UMTR chat forum.

www.umtrdragrace.com

[L79racer]

I just registered. Looks like a cool site. Thanks!!!