3 link rear suspension

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3 link rear suspension

Post  dr's wife racing on September 28th 2016, 12:34 pm

Anyone one here ever work with a drag car with a three link rear susp. ? Tube chassis big tire car with coil overs dual anti roll bars ?
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Re: 3 link rear suspension

Post  rmcomprandy on September 28th 2016, 7:05 pm

dr's wife racing wrote:Anyone one here ever work with a drag car with a three link rear susp. ? Tube chassis big tire car with coil overs dual anti roll bars ?

All the time.
However, there are at least two different 3 link type set-ups.  One uses a "Panhardt" rod and another uses a "Wishbone" center link.
And, Inverted 3 link suspensions are usually only seen on road race vehicles with rear brake torque rods.

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Re: 3 link rear suspension

Post  dr's wife racing on September 28th 2016, 9:15 pm

This one has a wish bone type.  It has one large link on tthe pass side it is moved well  inside the frame rail. any thoughts on this type set up. It is set up with 60 inch wheelie bars.
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Re: 3 link rear suspension

Post  DILLIGASDAVE on September 29th 2016, 3:50 am

From what I have seen and read a conventional "drag" 3-link has 2 bottom bars (similar placement/layout to 4-link bottom bars) and one top bar sitting on the passenger side fairly close to the driveshaft. And they will body-roll like crazy during the launch without a decent sized beefy anti-roll.

Warren Johnson tried a 3-link waaaaaay back in the day (I think it was one of his IHRA or match race cars, and not one of the NHRA cars) back before anti-rolls were a thing in P/S, and it had a ton of body-roll.

And supposedly one of WJ's later Don Ness cars was rumored to be either another attempt at a 3-link car, or possibly an attempt at a swing-arm car. Either way the rumor was he then quickly went right back to a conventional 4-link car.
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Re: 3 link rear suspension

Post  dr's wife racing on September 29th 2016, 8:46 am

This one has dual anti roll bars.
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Re: 3 link rear suspension

Post  Curt on September 29th 2016, 11:02 am

I sure there is a reason that none of the major chassis builders are building them for drag cars. There are plenty of good ideas, and a 3 link works great on a LTO car.
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Re: 3 link rear suspension

Post  dr's wife racing on September 29th 2016, 10:10 pm

While you may be correct, what I am looking for is ideas about how to help someone out. I've not seen one inn a LTD
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Re: 3 link rear suspension

Post  DILLIGASDAVE on September 30th 2016, 3:51 am

As far as setups go the drag 3-link can't use the top bars to adjust/shift side-to-side weight/preload around to correct a crooked launch (like you do on a 4-link) because you only have the one top bar to work with. IIRC about all you can do with the top bar on a drag 3-link is adjust the I/C placement & set the pinion angle.

That means if you need to correct a crooked launch with a 3-link you have to either adjust one of the 2 bottom bars to pull the housing off dead-nuts square with the car's nose-to-tail centerline (in effect adjusting in some wheel base stagger at the rear end). Or stagger the wheelie bar wheel heights (off the ground) from side-to-side to correct a crooked launch. Or use the anti-rolls to shift weight/preload around to correct a crooked launch. Or stagger the rear shock spring seat/spinner heights side-to-side, and/or stagger the rear shock valving side-to-side (when not using an anti-roll)........or combo of some/all of the above.

Post some good pics of the 3-link layout.
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Re: 3 link rear suspension

Post  dr's wife racing on September 30th 2016, 10:11 am

We're at the NMRA race this weekend. I'll get some good pics and post them this week. There are 3 pro mod cars around here running in the low 3.90's. So I know they will work.
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Re: 3 link rear suspension

Post  dr's wife racing on May 22nd 2017, 10:00 am

I still suck at posting pic's.
We have been playing with the three link car. So far so good. Spent a lot of time getting every thing square roll out on rear ties equal ect. Set every thing neutral. I have my old 10 liter in it. It went straight and had a 1.24 60 ft and drove good but wanted to spin and stand up at same time . Track was good
Took it home added drop spindles and moved instant center back and up a little. Added 4 deg. pinion angle. It was a Zero. It went a 1.15 60 foot almost no wheel stand Drives good the rest of the way. This was on a bracket prep track at I-22
Going to add some power and twist the old 10 liters tail a bit to see how it behaves.
So far so good it has behaved and responds to adjustment's very similar to a stock suspension car with a triangulated four link.
By the way it is on a 10.5 tire.
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Re: 3 link rear suspension

Post  460bronco on May 25th 2017, 9:13 pm

Was the suspension compressing or extending at the hit with the old settings? And what's it doing now?
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Re: 3 link rear suspension

Post  DILLIGASDAVE on May 26th 2017, 3:32 am

Upload the pics to a picture hosting site like photobucket.com, and then post (or embed) the photobucket links here.
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Re: 3 link rear suspension

Post  dr's wife racing on May 31st 2017, 10:29 am

I will see if I can. I have video but no luck getting it up loaded.
With dual anti roll bars body roll has not been a issue to this point. Was afraid it would be as this car is heavy.
We ran 5.30 this weekend. Went 4 rounds. Went out in simis due to a .393 red eye. Car went 5.30 with a one.
It tries to extend. No problem controlling extension. It has afco big guns which seem to work very good
Over all car works works good. It likes to be dead square. With every thing in the rear totally neutral.
Best 60 foot so far is 1.15 with a 1. Mph 134. I cleans the tune up a bit and it was on a pass that was a full 10 th faster at the 330 and up a couple mph but had a strange failure. The master switch fell apart. Should have been a high 5.0 pass
If anyone wants I'll send you the video to up load.
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