Maverick Grabber project in the UK

Here is the later part of the race, I am having issue uploading due to its length. Throttle stuck open hence the spin.

http://youtu.be/7CWK7-na5HQ

 

Very, Very nice, certainly got my blood pumping a little faster.........especially when you spun.........................motor sounds really healthy also.

 

nice!.. that looks like you must have had a blast!

is it just the camara/track?.. or do you have a bit too much height/bounce in your front springs?

 

Cool vid...That right hand chicane looks like a very tight turn in.

 

Well spotted yes it is a bit soft at the front and high. now its settled down a bit I will modify/lower it as handling was could have been better. It was its first time out

 

Warm up laps and race start

 

Noticed the air pressure really lifting the rear edge of the hood {bonnet?} up..

 

Yes it was, One of the threads was a bit weak on the hinge so I have to sort that out. I shall put that on my list of things to do

 

Looks like fun, I bet once you get it sorted out its going to be the car to chase...

 

Thanks Ken

On the straights I was pulling away from everything and not by a little it was car lengths. A bit of messing around and im sure it will be on pace.

Regards
Phil

 

Hi again Phil.

Please don't take this the wrong way as it's only intended to be constructive criticism to fine tune and improve that already awesome car you've got there.

From what I've seen so far in the race footage.. you're springs are not just too tall(which causes a lot of stored energy and gives too much travel/bounce).. but appear to also be too soft as well. I read back from the beginning of the threads start and it appears that you've already upped the rate from stock but you may still be too light. Cutting them will continue to improve the rate.. but I fear that the load bearing capacity may end up on the lighter side once you achieve the desired height.. and you may bottom out on major dips at speed on some of your tracks. Not good for the safety as the stock spindles can easily be broken by such things when using sticky tires.

The other thing to consider is that the body roll seems to be rather excessive for a lighter race car like this as well. Which would be immediately improved with a stiffer spring rate up front. I would also seriously consider adding a thicker anti-roll bar up front(we have a custom 1-1/8" unit being made for some of us here that you could easily get in on since production may not have ramped up for our special run just yet).. either in conjunction with a stiffer front spring.. or at least in lue of.

This/those mod/s alone will help you keep up with those little roller skates through the corners a bit better and also allow you to go into them deeper/faster under more power and come out much stronger/earlier while avoiding that "weight shifted" or maybe better to say "unsettled chassis wheel spin" you're running into there. Of course a little wider rear tire would'nt hurt in helping it plant all that torque too.

Also.. I'm curious as to how much Shelby drop you ended up running here? Not sure what the rules will allow.. but another option would be to use a taller balljoint up top to achieve the same "improved camber" result.

I really dig your car and hope to eventually go autocross/club racing with mine after a few years of street/drag race duty too. Most of my mod's will be hand fabricated as well.. so I usually pay pretty close attention to cars like yours. If you haven't checked Streamliners build thread out yet(or maybe it was just in his pic gallery)?.. it's surely worth a look as he has some good grassroots/homebuilt/pro mod's on his car too.

 

It's really hard to look at video and try and diagnose issues but have you had the car on 4 wheel scales to see what each corner is doing.
I agree with Gary about a little more spring in front and maybe the possibility of trying an adjustable swaybar setup like this; http://www.powergridinc.com/swaybar.asp
Being able to adjust the bar can really make a difference on any track and if you know the weight on each corner this can help in making the adjustment more effective. I don't know about the rules of your club, but having this type of fine tuning can make a big difference in the way the car corners...............just my 2 cents worth.
Wish you were about 6,000 miles closer as I'd love to watch and be part of your pit crew.
Keep the Shinny Side Up

 

Thanks I really do appreciate all input on how to sort these problems out and I would never take any input the wrong way. One problem I get having one of the only Mavericks in the uk is finding the right parts so having someone who is clearly very clued up on the subject really helps. I did the Shelby drop from a metal template of Ebay I think it was about and inch. I will measure the roll bar and see what I have on it, I dont think its as big as your one your having made.

What spring rate in your opinion would suit the racing im doing?

Sorry I hope you dont mind but I may ask loads of questions

 

While olerodder is right in that it's tough to see and correctly diagnose/troubleshoot from a video.. all I was really going off of is the tell-tale front body roll.. as well as the audible transitory unloading of the inside rear tire as you quickly chicaned and abruptly got back on the throttle. Excessive body roll.. at least for a race car anyways.. is even quite evident when you look at the beginning of the warm-up lap as you attempt to feel the car out and warm the tires.

The front and rear spring rates must work together to give a proper handling car. Example, if the front spring package is too soft compared to the rear spring package.. the rear tires will loose traction before the front (over-steer). If the rear spring package is softer than the front, the front tires will loose traction before the rear (under-steer). These are just general rules of course and sway bars can change things up a bit in that regard.. so ymmv depending on the component matchups. Stickier race tires also have an impact since under full acceleration, braking , and cornering, the tires set the limit for the amount of front to rear weight transfer that can be generated. And the amount of front end roll, lift or dive is created by those forces, and resisted or limited by the springs. In a nutshell, more grip= more spring rate needed, or else more front roll, lift/dive will be generated.

As for rec'ing a particular spring weight?.. the car is light to begin with and gutting it for full race duty will obviously only help matters even more as to lowering the typically required spring rate. Without knowing the rear leaf springs rate and size of the anti-roll bars being used.. I would have to just ball park the requirement at around 500-550 lbs/in for a full racer like yours. Maybe ask Streamliner what his setup is? I've run a few 650lb sport springs on full interiored small-block equipped cars before(1 was gutted for street racing with rear battery relocation.. but still surely heavier than yours).. and they can definately be bone jarring over rough roads/railroad tracks.. especially with poly bushings. But the handling was superb with very nuetral attitude and predictable response and recovery even well past adhesion loss.

As for the amount of UCA drop that you used here. While it certainly didn't hurt matters to go with that 1" drop.. personally I would have leaned towards a more aggressive 1.5 - 2" drop for a track only car. Heck.. I've done 2" drops on racier street cars and although you end up needing a negative wedge kit and run into the law of diminishing returns fairly quickly with anything past 1.5 inches.. it does improve things even more over the basic 1" drop.

From just a few quick measurments and shorter time of extensively studying my 71 Comets tower.. to be able to effectively run the full 2 inches(plus the improved caster off-set), I'll need to notch the frame rails to keep the UCA from contacting the top portion of the rail during full rebound.. but IMHO.. and based on experience with 3 other cars running the full 2 inches so far.. that's a small price to pay for the slight extra gains which can be had from going that extra inch of drop. I've seen some cars that allow the frame rail contact to act as a suspension limiter to keep really short springs from walking around in the perch's.. but I myself wouldn't be too comfortable with repeated contact like that and would prefer to just run a cable type limiter if need be. Another plus is that the extra .5 - 1 inch of drop will also lower the car a bit more too.. maybe another 1/4 inch or so depending on how far you go.

Anywho.. it's getting late now.. and at this point I don't have much more to add. I'd be very interested in hearing what Streamliner would add to the discussion on the matter since he has a very similar purpose built car running at around the same weight.

 

Thanks for your advice, I will update when I get a chance to work on it.

Cheers Phil