ALFAGTV6.COM

TS_turbo · Post by **TS_turbo** » Sat May 26, 2007 7:30 am

IMO rising roll center wil improove handling on car with soft spings (Tbars) higher roll center will make car to roll less and more importan suspension geometry will have beter camber curves ... if dinamic camber curve and bump steer are keep close to acceptable limits when cornering ... of course we are not talking about dead soft stock spring rates and ride height ! making suspension siff like hell is comon practice for strut FWD cars ... double wishbone suspension layout have advtage of keeping good camber curves and good handling with soft spings(lots of wheel travel in both bump and droop) if set up corectly... other big disadvantage of transaxle alfas is very narrow wheel tracks

Echo Leader · Post by **Echo Leader** » Tue May 29, 2007 4:29 am

TS_turbo wrote:higher roll centre,lower gravity center, wide track

Mats wrote:Just remove all the stuff that doesn't lower laptimes and optimize the stuff that does. ...

ooooh, so that's how it's done!

I'll get right on these suggestions.

Grant, I guess I just don't know what 'rates' the T-Bars are. So I can't really compare to the RSR compression numbers...

I am thinking about this correctly right? For a given amount of twist in the T-bar we'd need to convert that into something like "inches" at a fixed reference point and compare the RSR compressions at that point as well? Say at the hub face or, better yet, at the shock mount point ....Otherwise how do we compare the T-Bar numbers to a Coil numbers?

And with the RSR we'd need to factor in the stock T-bar as well....again at a reference point, probably the shock mount on the LCA....

Anyway, I would think that the 30mm front AR-bar recommendation that RSR makes, with the big spring rates of the combined stock T-bar and the additional coil over make a strong arguement that the geometry really needs to be addressed if you're going to attempt a solution that doesn't involve basically hardening the front until movement is nil.... decent thinking??

TS_turbo wrote:IMO rising roll center wil improove handling on car with soft spings (Tbars) higher roll center will make car to roll less and more importan suspension geometry will have beter camber curves

Yup, I'm with you. I just think that tackling the geometry is a bit tougher to get 'right' and universally implemented on customer cars, then tightening the front as much as possible using AR-bars and adding coils to the T-bars. I'm thinking this may be why the RSR kit is engineered the way it is...

Micke · Post by **Micke** » Tue May 29, 2007 4:34 am

What you do is reduce both suspension types to spring rate at the wheel.

Echo Leader · Post by **Echo Leader** » Tue May 29, 2007 5:45 am

Micke wrote:What you do is reduce both suspension types to spring rate at the wheel.

Thanks! This is a calculation specific to each vehicle then? So chosing contact patch center vs. outer edge is a non-issue so long as I'm consistant?

grant · Post by **grant** » Tue May 29, 2007 7:25 pm

No need; Potenziato from the alfabb was kind enough to copy a page from a shankle catalog as well as swap spindles with me (he has RSR coilovers and wanted to get rid of his drop spindles, b/c they put the coilovers out of their range of adjustment).

So after many hours under the car, and with a 9 foot long pole, I was able to twist my 27mm torsion bars enough to remove the A-arm bolts (I think 30 and 33mm torsion bars must requre the engine to be lifted enough to slide in the LCA bolts from the engine bay. Once you lower your 116 with stiffer torsion bars, the LCA bolts no longer clear the LCA! Before I barely was able to get it in by grinding part of each head of the bolts off to eek by the LCA.

Anyhow:

"116 & 119 Alfetta/GTV 6/Milano Torsion bar specifications:

GTV6 Early model:
stock bar:
Rate -- 96lbs/in Diameter -- 23.5mm Length--989mm
Sport Bar:
Rate -- 134lb/in Diameter -- 25.4mm Length -- 989mm
SS Bar:
Rate -- 179lb/in Diameter -- 27.3mm " " -- 989mm

GTV6 Late and Milano:
Stock bar:
Rate -- 93lbs/in Diameter -- 22.8mm Length -- 932mm
*No wonder I hit my oil sump so often with the stock setup!
Sport:
Rate -- 143lbs/in Diameter -- 25.4mm Length -- ""
SS:
Rate -- 191lbs/in Diameter -- 27.3mm Length -- ""

So, I have an '84 and I think that means I have the longer, early style bars.

Another interesting thing I learned was that the GTV6 has stiffer rear springs in the rear than the Milanos do. I'm not sure how much, but the SS springs I have in the rear (143lb/inch) are 39% stiffer than stock on the GTV6 but are 57% stiffer than stock on a Milano. Also, SS springs apparently came in two lenghts, one that lowers an early Milano by 1 inch, and another that lowers it 2 inches.

The dissapointing news is that on my Verde, the drop spindles with bump steer correction reduced my bump steer by a large amount, but at the limit, didn't seem to do that much for my understeer problem. It felt better driving fast on a relatively bumpy road (bump steer correction?) but on a freeway onramp, the front tire howl was still there. I haven't given up entirely yet though, b/c my front camber is at like -1 or less, about the same as I had before. This is kinda funny, b/c on Potenziato's 24V Milano, his camber was roughly the same after he went back to stock spindles as before! The drop spindles were 1 and 1/16th inches longer.

I haven't been able to go to my usual testing spot so I wouldn't call the results conclusive yet, but so far they did less than I was hoping.

I'm going to try to get my camber to around -2.5 or more this weekend but I'm going to my GF's prom so I'm not sure.

Hopefully the results will be better for you Echoleader!

Barry · Post by **Barry** » Tue May 29, 2007 9:00 pm

Grant,thanks for the invite on You toob...

Make up a simple tool for the torsions.

Barry · Post by **Barry** » Tue May 29, 2007 9:01 pm

grant · Post by **grant** » Tue May 29, 2007 9:06 pm

Wanna explain how that thing works? How does the top part attach to the engine bay?

Huh? Whaaa? What about you tube?

Do you know anywhere to get cheap-ish 29-30mm torsion bars?

Post by **Zamani** » Tue May 29, 2007 9:59 pm

That's BarryTube. When you make it, it will be called GrantTube. But in general it is called a YouTube.

The threaded shaft goes through the shock tower and threads into the LCA's mounts. The threaded shaft also goes through the big tube in the engine bay. The big tube must have some kind of a nut in there. You turn the crank at the top of the big tube, which in turns brings the LCA up or down. So you can easily adjust the height of the LCA before you try to push the torsion bar back in.

Barry am I right on this?

Sadly I think this method doesn't work for bars bigger than 25.4. Because with bigger bars, the LCA has to come off as the bigger bars cannot slide out the back of the cross member.

BTW Grant, I think I've said it before. Suspension wise our car is fine. Spend money on other things like brakes.

Micke · Post by **Micke** » Tue May 29, 2007 10:18 pm

Grant. Why should only the spindles reduce understeer?
Do you have any picture of the spindles? Just curious.

grant · Post by **grant** » Tue May 29, 2007 10:39 pm

I don't know about your car Zamani, but mine's an understeering pig...it's not fun AND it's slow. My car's so slow around the track, I haven't really had to worry about brakes

Before I had drop spindles, my car would lose camber when cornering hard...so -1 degree negative would turn into like positive X degrees camber...reducing front grip.

Now with the drop spindle, it's a little bit better, but I think I need more static camber regardless. The drop spindles set the LCA lower for the same ride height as before changing the spindles. That would raise the roll center...what effect this has on my 28mm front sway bar, I'm not sure, the car seems roll about the same. It does seem quicker in transitions actually. The drop spindles also reduced my bump steer quite a bit. I wasn't sure what bump steer was before, but I think I've got it now.

Supposedly the drop spindles would raise my UCA, which should further effect my camber gain in a good way, but that's not the case. On my drop spindles, with the car sitting at the same ride height, my UCA's are the same as before. Only the location of the lower ball joint gets moved. A well known alfa racer in California, Larry Jr, mounted his ball joint below the UCA with nuts and bolts, I think. This made the UCA more angled.

I'm going to set the camber to about -2.5 and see how it goes. If that doesn't kill th eundersteer, I'm not sure what else to do short of getting custom springs for the rear.

Zamani, maybe you should take my car onto an onramp some time?

Post by **Zamani** » Wed May 30, 2007 12:03 am

You need to move the battery to the back. Do you still have the condenser in the front? Remove that too. Compressor? Then euro bumper is next.

The bumper and battery alone are worth 70 lbs at the end of your car!

-2 deg. camber will also help.

Call up Vince Bachu in the UK and ask him for a quote for euro bumpers. He's useless with emails.

grant · Post by **grant** » Wed May 30, 2007 12:08 am

I'm thinking of getting a few sets from Taiwan, along with a few sets of carellos (if they use those there).

AC is long gone. If I can't get the euro bumpers, I might hallow out some USDM ones a la Jes.

Some time I want to check out your battery relocation job in detail. I'm really clueless as to what is OK and what isn't as far as cable routing, battery mounting. Mount the battery in the spare tire well or up against the gas tank? I dunno.

This is a bit frustrating, as I pretty much have a Shankle SS setup. Other people with similar setups repor ttheir cars oversteer. I don't get it!

Mats · Post by **Mats** » Wed May 30, 2007 12:12 am

grant wrote: A well known alfa racer in California, Larry Jr, mounted his ball joint below the UCA with nuts and bolts, I think. This made the UCA more angled.

That doesn't make any sense at all, the joint is in the exact same position and that is all that matters. The arm itself can look like a banana (like on the IMSA cars) or whatever, as long as the joint doesn't move it's function will be geometrically identical.

What you need is that same as I have been saying for a while now: More spring rate up front!

grant · Post by **grant** » Wed May 30, 2007 12:17 am

Besides going to coilovers, I don't know how else I'm going to get more spring rates up there. I don't know of anyone that sells anything larger than a 27mm bar, besides Andy'd full race 33mm. I would like a 28-30mm I think, but access is denied. Besides, the car drives pretty well on backroads, which I'd be giving up with higher spring rates. I'm not as worried about total grip as I am balance. I just want to get this thing nuetral! And so far this car has been built up as a budget racer for a poor college student. The 3.0 is dead stock, and will be for a while. Therefore, I can't justify spending $1200 USD or w/e it would be to buy some bars from OZ and ship them to my door.

I'm not sure if I agree with you about the ball joint thing. Somehow it seems that if the UCA is at a greater angle than stock, for the same wheel movement in compression, the top will want to tuck in more.

Maybe I need to think about it more?