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Gremlin Traction Woes

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PHAT69AMX View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2020 at 7:22pm
What P.S.I. hot in the tires?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2020 at 8:39pm
I normally run 16-18 psi, did drop them to 14 last time when it wouldn't hook up and it didn't really seem to help.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PROSTOCKTOM Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2020 at 10:41pm
Originally posted by WesternRed WesternRed wrote:



Looking at moving weight around, about the only thing I can think of is moving the battery from the engine bay to the rear, but this would only be an incremental change.
That is the first thing I would change. That alone depending on the battery your using could be a 2% change in front to rear weigh bias. The other thing I would do if that doesn't yield you enough gain is re-install the back bumper. You cant go fast, and you cant be consistent if you can't hook it up. I have friend that has a Duster. One winter he decided he needed to put the rear of the car on a diet, so he bought aluminum center section (9" Ford rear), aluminum spool, light weight wheels, fiberglass truck lid, fiberglass bumper, lexan rear window, and a lite weigh battery. He worked at it and removed 150# of weight. The car slowed down .15 in the 1/8 mile. He bought new tries and tried everything to get the performance back to no avail. After a half of a season of banging his head on the wall he finally listened to an old racer that had 50-years of racing experience and brought the car to him. The next day he had the car ready for him to run again, but he wouldn't tell him what he did to it and told him to just go race it. Couple days later he took it to the track and amazingly the car ran the numbers it had prior to the very expensive weight lose program. So what did the old racer do to make to run again? He took the rear fiberglass bumper off and made a really thick steel plate that fit hidden inside the rear bumper. That plate weighed 150#. I've never forgot that story and I've never removed weight from the rear of a bracket car that didn't have a 4-link suspension from that day forward. 

Tom 


Edited by PROSTOCKTOM - Oct/20/2020 at 6:19am
1949 Ford Business Coupe
1969 AMC Rambler Rouge, Tube Chassis Race Car
1974 AMC Hornet Hatchback, Wally Booth Outlaw NPS Race Car Project
1980 Ford Fairmont Futura
1990 Ford F-350 Supercab Dually
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Post Options Post Options   Thanks (0) Thanks(0)   Quote XJ6 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/20/2020 at 5:43am
Originally posted by WesternRed WesternRed wrote:

[QUOTE=XJ6]
Here is a Gremlin that appears to have a Cal Trac setup and soft front springs running some impressive ET


Now that's what I'm talking about. I notice the front end actually squats on the line and it has way more suspension movement than mine. Would love to know what the suspension specs are on that thing.

And here they are:

Up front, the suspension is stock AMC with Viking double adjustable shocks. At the rear Caltracs traction bars, split mono-leaf springs, and double adjustable Viking shocks complement the Ford rear.

The Viking shocks look like nice pieces. Around $200 a piece from what I can tell but might be the last set you will ever buy. I may switch to them on my Spirit which is running a similar setup as that Gremlin , Caltrac mono leafs and bars with a 9" Strange rear except Im using the Comp Engineering single adjustable shocks. In the front I cut a full coil off aftermarket springs and full poly bushings too
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Oct/20/2020 at 6:16am
From reading one of the articles on that Gremlin, the Caltracs made a big difference, so that’s probably a consideration.

Looking for alternatives to the Opentracker spherical bearing conversion, maybe just order some Heim joints from Speed  Motors. Does anybody make a tubular upper arm that works with the factory spring mounts?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote XJ6 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/20/2020 at 8:40am
Looks like Control Freak offers a control arm kit that includes the Viking shocks

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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Oct/20/2020 at 7:20pm
The control freak setup looks nice, but maybe overkill for what I'm trying to achieve.

Roll on with the quick fixes for now, front shock spacers:



Gives me this much extension, which is about 1/2" more than before given other limitations that come into play. Hard to imagine it ever gets anywhere near this high on the track:



Probably going to have to lower the front and look at some options to get rid of the rubber bits to loosen it up a bit more in slightly longer term.

Also decided to knock out a new timing map to bring most of the advance in between 4000 and 5000 rpm, the boxed section is the only bit that really matters here. I can load this fairly easily on the night to see if it helps:



Battery location will be the next in order of priority. I have put an enquiry in with the Aussie Caltrac distributor to see if they can supply some before looking further afield as they are not really that expensive in the scheme of things.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Oct/21/2020 at 5:02pm
And the outcome was pretty much no improvement. Did manage to get one run where it hooked up, ran a 1.76 second 60' and 12.04 second 1/4 mile, I think mostly from roasting the tires a bit more than usual in the burnout.

Here is the data log of that run, mostly to show that timing map worked as intended for anybody who is interested:


This one below, I tried to ease it off the line gently and it lit up the tires almost immediately:

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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Oct/23/2020 at 5:53pm
Back to more mundane stuff, started work on the battery re-location, a mate at work is going to zip it up for me:



Off the shelf is just too expensive down here in Australia, would be $150 for the plastic Moroso box and $260 for the Taylor aluminum one.

I'm putting a rough plan together to build some front end components and will probably look at Caltracs for the rear.

Also noticed the the rear sits maybe 1/2" lower on the drivers side, so I'm going to have to look into that a bit more. 


Edited by WesternRed - Oct/23/2020 at 5:55pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Oct/28/2020 at 3:56pm
Well, what difference a week makes, track was much better last night, no tractions issues whatsoever. Put my original timing map back in and actually ran a PB 60' time of 1.679, mostly 1/8th mile runs, we have a heads up radial thing that I'm running in, but did a couple or  1/4 mile runs in as well with a best of 11.84, which is about a tenth off a PB. Running 7.5-7.6 in the 1/8th.

I'd say the most if not all of the improvement was track related, but a few things I did were:

Roasting the tires extra hard in the burnouts, so maybe I've finally worn the winter crust off, my new benchmark for a good burnout is if the cabin is full of smoke afterwards. Sometimes it can be a tricky car to hold in a big burnout, but I'm getting better at it, having a rev limiter now it a bit of extra piece of mind.

Did cut half a coil off the front springs last weekend, which I can't see actually doing much in the scheme of things other than lowering the front of the car a bit, so it is a slightly more aerodynamic brick. Took the shock spacers back out too.

Battery relocation didn't get completed, so something to look forward to for next time.
I've finally given up drinking for good...........now I only drink for evil.
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