Make it handle

[jimmydean]

Rob, I loved seeing the shots of your Bullit tearing up the course in the Trucks Throwdown (or whatever they called it). Based on your lap times, it sounds like you have it pretty well dialed in. Nice work!

[robnolimit]

Quick update. We are victorious again! By the lunch break on friday, we had set the fast lap. Not just for trucks, but for EVERYBODY. As the racing continued, we pushed our numbers down even farther, and no one ever caught us. First Truck Class win of the season, and the overal fast lap (first time I've done that). I'll get some picts and video up soon.

[chapster]

Congrats Rob,

looking forward to seeing some video.....

[Greywolf200]

I saw the roof of the Effie on the roadcourse and several shots of the Hotchkis truck at the Ultima Street Challenge on HDTheater but neither even got an honorable mention on air, what's wrong with these people?

[djw32]

Originally Posted by robnolimit

Quick update. We are victorious again! By the lunch break on friday, we had set the fast lap. Not just for trucks, but for EVERYBODY. As the racing continued, we pushed our numbers down even farther, and no one ever caught us. First Truck Class win of the season, and the overal fast lap (first time I've done that). I'll get some picts and video up soon.

What was the competition like? I imagine Rob's 69 Hotchkis truck was attending...

[Hotchkis]

Originally Posted by robnolimit

Quick update. We are victorious again! By the lunch break on friday, we had set the fast lap. Not just for trucks, but for EVERYBODY. As the racing continued, we pushed our numbers down even farther, and no one ever caught us. First Truck Class win of the season, and the overal fast lap (first time I've done that). I'll get some picts and video up soon.

Rob,
Congrats on setting the bar high. We’ll be giving you a run for your money this season.

[chevy2tom]

Rob, I pm'd you a few weeks back about using your new rear shock/track bar set up on my 71 C20. I know you have alot going on, any info if it will fit or if you can make new U bolt brackets?
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[Walkersan]

Please don't shoot me for asking, but I keep reading about move it lower and back for better balance and lower CG. I love my V8s, but I also understand the potential power in a forced inducted modern fuel infected V6. Say something like a donor from a Camaro. Something like what Jay Leno did to his.

http://blogs.insideline.com/straight...6-to-sema.html

The reason I ask is this. All along I have planned on a 5.3 swap and later turbocharging it. Modernize the old truck for drivability and fuel mileage too. All this talk about low and back got me thinking about this swap instead.

Thoughts?

[SCOTI]

Originally Posted by Walkersan

Please don't shoot me for asking, but I keep reading about move it lower and back for better balance and lower CG. I love my V8s, but I also understand the potential power in a forced inducted modern fuel infected V6. Say something like a donor from a Camaro. Something like what Jay Leno did to his.

http://blogs.insideline.com/straight...6-to-sema.html

The reason I ask is this. All along I have planned on a 5.3 swap and later turbocharging it. Modernize the old truck for drivability and fuel mileage too. All this talk about low and back got me thinking about this swap instead.

Thoughts?

Anytime you're reducing mass over-all or optimizing its placement within the chassis, it will improve things.

An alum headed 5.3 will be lighter than a traditional sbc. Is the 5.3 you're referring to all alum or cast iron block/alum heads? The better idea might be the 5.7 LS1 or 6.0 LS2 as they're all aluminum & would help offset the additional weight of the turbo related equipment. You could also opt for one of the remote turbo set-ups that put the turbo out back. The alum motor reduces mass up front & shifting the weight of the power adder to the extreme rear can help balance things.

[Scot_Douglas]

One question I have that I haven't found a clear answer for is how far the motor can be moved back before you run out of realestate. I've fabbed up mounts that let me go with 1" or 1.5" of setback - hopefully I can get the 1.5" without modding the firewall.

My current suspension setup is a 93 T-bird IRS and a 2" shaved front crossmember with 2.5" drop spindles. I haven't figured out what shocks I am going to use yet, as I haven't designed my top shock mounts yet. I also will move the fuel tank to the rear, along with the battery.

I've also added a 87 T-bird steering rack and swapped upper control arms to see the results of "poor man's caster" - I've seen it mentioned here, but can't find actual feedback from anyone that's run that way (maybe because they died on the test run?). Figured I'd give it a try and see what I can figure out. My luck, I'll make it a PITA to drive - but I won't know until this summer when I hope to have it back on the road.

[robnolimit]

Glad to see everybody is starting to think about this stuff. V-6 could be a good choice, but remember that you need torque to get the weight out of the corner. If the turbo v-6 spins quick, you can make torque with gears.

I'm sorry about some answers that you have been waiting on, now that wer'e back from texas, I'll get back up to speed.

[Walkersan]

Something else I had rattling around in my head recently about IRS. With the huge reduction in un-sprung weight on a IRS, is it the overall weight that is keeping more people from using this type of setup? Complexity maybe?

[slow4dr]

Originally Posted by Walkersan

Something else I had rattling around in my head recently about IRS. With the huge reduction in un-sprung weight on a IRS, is it the overall weight that is keeping more people from using this type of setup? Complexity maybe?

Cost & Complexity would be my #1 & #2 reasons

[Scot_Douglas]

Originally Posted by Walkersan

Something else I had rattling around in my head recently about IRS. With the huge reduction in un-sprung weight on a IRS, is it the overall weight that is keeping more people from using this type of setup? Complexity maybe?

Originally Posted by slow4dr

Cost & Complexity would be my #1 & #2 reasons

I didn't weigh things when I changed the rearend out, but the Tbird IRS didn't seem to weight a whole lot more than the 12 bolt and trailing arms and associated parts.

Complexity? What? Instead of two pivot bushings to replace in the old trailing arm suspension, I have (I think) 14 or 15 total in this bird rear end. Totally overlooked that one when shopping around. I planned on shortening my wheelbase 5" and going with a 4-link solid axle. When I looked at DOM tubing, rod end and other associated prices - the $150 for this IRS unit seemed like a steal! Not to mention it came with disc brakes.

Of course, I checked the bushing prices AFTER I started the install. Live and learn.

I am excited to see how the truck rides and handles with the mods I've made - I didn't start out to build a truck for the track - but the more I read here and see what can be done with what we have, the more excited I am to try an autocross or two with it.

[slow4dr]

Luckily, the trucks track width and frame rails are wide enough to house many of the factory takeouts available. I tried to use a C4 Vette IRS in an early Nova. I had two options here, expensive wheels with huge backspacing or cut everything down(halfshafts, batwing, control arms, tie rods etc) to shorten the track width to make it fit in the car. When it was all said and done I would have had to do both to make it fit and work properly. At the end of the day even the more expensive and rare Dana 44 option still wasn't capable of holding very much HP when abused(which I had full intentions of doing). I ended up buying a 9" and made a custom 3-link with a watts link for the price I sold the C4 vette IRS for. If I had to do the same thing today I would use the GTO or G8 IRS.

[Scot_Douglas]

Originally Posted by slow4dr

Luckily, the trucks track width and frame rails are wide enough to house many of the factory takeouts available. I tried to use a C4 Vette IRS in an early Nova. I had two options here, expensive wheels with huge backspacing or cut everything down(halfshafts, batwing, control arms, tie rods etc) to shorten the track width to make it fit in the car. When it was all said and done I would have had to do both to make it fit and work properly. At the end of the day even the more expensive and rare Dana 44 option still wasn't capable of holding very much HP when abused(which I had full intentions of doing). I ended up buying a 9" and made a custom 3-link with a watts link for the price I sold the C4 vette IRS for. If I had to do the same thing today I would use the GTO or G8 IRS.

Well, with my application - and I am not discounting my ignorance / lack of experience - I couldn't keep the rear frame rails because they got in the way of upward travel. I think the 6"-7" drop in the rear is the culprit there though. :LOL: truckirs.com uses the same rearend under an old ford and durned near make it a bolt-in affair.

The wms-to-wms of the bird IRS is 63.5"; I'm using 1" adapter plates / spacers on each side for a 7.5" wide wheel with a 38mm negative offset (2010 Camaro).

[slow4dr]

LOL, I ended up moving my rails as well.

[robnolimit]

We have built a few trucks with the Crown Vic IRS, using the factory cage. I have to say that they ride great. We use a 9000 style bag, or a 325 lb spring, as the iRS will naturally want a big more rate that a solid axle. The rails do need to be moved, C'd, or re-shaped to clear the upper arms, but do that after the cage is welded in and its pretty easy.

[Scot_Douglas]

Originally Posted by robnolimit

We have built a few trucks with the Crown Vic IRS, using the factory cage. I have to say that they ride great. We use a 9000 style bag, or a 325 lb spring, as the iRS will naturally want a big more rate that a solid axle. The rails do need to be moved, C'd, or re-shaped to clear the upper arms, but do that after the cage is welded in and its pretty easy.

I've been making it up as I go along.



Also, I attribute this thread and YOU, ROB, for making me really want to get this truck to handle! (thank you!)

[M5-]

Originally Posted by robnolimit

We have built a few trucks with the Crown Vic IRS, using the factory cage. I have to say that they ride great. We use a 9000 style bag, or a 325 lb spring, as the iRS will naturally want a big more rate that a solid axle. The rails do need to be moved, C'd, or re-shaped to clear the upper arms, but do that after the cage is welded in and its pretty easy.

Sledding season is almost over so its time for me to dig the 65 out of the snowbank and do some more work on it. I know I read this on here somewhere but what years of Crown Vic are we talking and if I remember they use the 8 3/4" rear end? Will that have a posi in it?

Thx M5

[robnolimit]

Thanks, your progress looks good. When the truck is finished at ride hieght, try to set the spring hieght so that the half-shaft is level. Keep building.

[killerpickup]

Have you guys heard of team 321 in Florida, they seem to have their s--t together on the independant rear install. Reach them at Truck IRS.com. killerpickup

[Scot_Douglas]

Originally Posted by robnolimit

Thanks, your progress looks good. When the truck is finished at ride hieght, try to set the spring hieght so that the half-shaft is level. Keep building.

Thanks! Means a lot coming from someone that does it for a living.





I wasn't sure about where to set the IRS, but guessed the same starting point that you mention - I'm close.

Originally Posted by killerpickup

Have you guys heard of team 321 in Florida, they seem to have their s--t together on the independant rear install. Reach them at Truck IRS.com. killerpickup

A few posts back I mentioned them - they have great info and a pretty good method for getting the bird IRS into older trucks. Problem for me is that my rails get in the way - which is less trouble on a skinnier leaf-sprung frame like the Ford they show a buildup on. Also, and this is just my personal opinion, I didn't like how the end product looked on the front of the subframe. To be specific - the outriggers they made to allow it to be a near bolt-in affair - just doesn't "flow".

No matter - I spent lots of time reading and re-reading their site. They offer a pretty good way to go with IRS on the cheap.

[Barney Rubble]

wow, amazing thread, just spent the morning go over it, understood a fair bit.
robnolimit - appreciate a vendor being open to questioning, and responding thoughtfully.

New to pickups first post new truck
I want to improve the handling, but not for track (I have a car for that), but just so she drives better. Don't like bouncing along our rough roads. She has leaf/shocks, PS, Power drums; 17" rims with a 6 bolt pattern; SB327.
I have been looking at the Mustang IFS kits...... with power rack; and I am impressed by the No Limit chassis package.
I don't really want her riding any lower, no plans to carry loads either.
The fuel tank will be shifted to the rear also.
Living in Australia is a consideration with shipping costs from the USA, but still with that, it seems to be much cheaper to buy from stateside.
Any thoughts?

[robnolimit]

welcome Barney. Thanks for the props. - what year truck are you working on? Also, we can build the IFS for rhd, we've done a few for aussieland and europe.