Project GatTagO

iTrader: (7)

Yesterday afternoon I got down to the task of of getting the car ready for the Holley LS Fest, which is only a couple of weeks away, and performing the few little upgrades that I had planned. First order of business was to take the front wheels off the car, break them down, install the wider inner hoop, reassemble, and reseal.

The wheels started life as being 8" wide. In case anyone was wondering, wheel width is measured at the area where the tire bead sits, not on the outside edges.



Here is the backside of the wheel. Notice the generous scalloping on the back side of the spokes and the hub area of the wheel. This is the reason why this particular wheel is only about 20 pounds. Also notice the generous amount of brake dust. I drive this car!



There are 40 fasteners that hold the wheel together. Once the nuts are removed, the wheel center comes out and the wheel halves can be separated. Notice the dead bugs on the inside of the wheels.



After disassembly, I cleaned the wheel centers with hot water and soap. This works very well to remove all the brake dust and general grime. The wider inner hoop was installed and the fasteners were torqued to 18 lb/ft, in two steps, and in a start pattern, much like when you torque lug nuts.



Here is the finished wheel, now 9.5" wide and ready for the new BFG Rival 275/35-18 front tires. Important safety tip: make sure you let the silicone dry before putting air in the tires. The pressure will penetrate the uncured seal and will leak, resulting in taking the tire off and doing the seal over again. Not fun!



Here is the rear Rival compared to the Falken 615...



Today I will be installing the Dodge 7/8" bore MC, so stay tuned for more updates.

Andrew

Project GatTagO

iTrader: (7)

As promised, here are some details for the Dodge 7/8" bore MC. This is what you get for about $60 bucks at O'Reilly Auto Parts. It is a MC for a 1995 Dodge Spirit with manual brakes (14" wheels). This particular model is brand new, made out of aluminum and has a plastic reservoir. These are all features that I like. Wilwood makes a nice 7'8" bore, direct bolt-in MC, but it has a reservoir lid that can only be taken off with an allen wrench. While it looks nice, I want to be able to check the fluid level without getting my tool box out.



This MC has two ports that have rather small fittings. The catalog description lists the outlet ports as being 3/8" inverted flair, but they sure seemed smaller.

The rear port of the MC is plumbed to the front brakes and nothing was needed to attache the line. The front port of the MC is plumbed to the rear line and required an adapter fitting that you can see in the picture. However, this adapter was too small for the fitting that was on my rear brake line, so what we decided to do was bend another line for the rear brakes. That way if I ever wanted to swap back to the other MC, it would be very simple to swap lines. We bent up a 5/16" line, using the old line as a template. It was fairly straight forward and simple.

The other issue with using this MC is that the mounting holes don't quite match the GM pattern. As you can see, we elected to notch the holes to make it easier.









The other issue with using this MC is that the pushrod hole is not as deep as the GM MC I was using, so the rod had to be shortened. The tip of the rod also had to be ground down slightly because the Dodge MC has a smaller diameter hole.

The bottom line is that this MC is a fairly easy swap into GM vehicles and is a viable OEM alternative to some of the aftermarket offerings. With a little ingenuity it can be made to work in applications that require a 7/8" bore MC.

The brakes feel very different now. The pedal feel is softer but I haven't really noticed a big increase in pedal travel. I am now easily able to lock up the brakes, when before I couldn't. Clearly the MC is generating more force at the caliper, which is what Ron was attempting to show with his spreadsheet.

A huge thanks to Ron Sutton for giving me the last needed nudge to make the swap to the 7/8" MC.

To wrap it up, here is a picture of the 275/35-18 BFG Rivals on the front.



There is mild rubbing on the sway bar at the extremes, but I don't see this as a huge issue. I may run a small spacer in the front if it become annoying, but for now I am going to work on a few other minor issues before the Holley LS Fest.

Andrew

Project GatTagO

iTrader: (7)

After I had made my previous posts, I realized that I never posted a picture of the MC as it was finally installed. You can see the new 5/16" rear line along with the adapter that was needed. The rear port for the front brakes worked as is.



I also want to make some comments regarding my first impressions of the Rival tires. I haven't really had a chance to test out the handling, but I can say that the tires are very sticky. I was driving and happened to go over a spot that has some loose sand and I could hear the tires picking up every little pebble as I drove over them. Also, with the Falkens, even when they were new, I could be rolling slowly in 1st gear, punch the throttle, and the tires would spin until I let off or shifted. With the Rivals, doing exactly the same thing, the tires dead hook. I am really excited to get the car out on the autocross and on the drag strip.

Andrew

kwhizz

Wow!!!.......Just went thru the entire thread.......What a great job and the attention to the little details .............and the continued "Tweaking".........Absolutely AWSUM!!!!!........Great Job Andrew!!!!

Ken

JelloB1afra

this thread is a wealth of information. thought i'd say thanks for your thorough documentation. also, the build is incredible

Project GatTagO

iTrader: (7)

If I can't toot my own horn, who will?

Got a nice 4 page feature story in the current (February 2014) issue of GM High-Tech Performance and a action shot from LS Fest in the current (February 2014) issue of Popular Hotrodding. Woot!!!

Andrew

Meangreen1

iTrader: (2)

Nice job, it's good to see someone on here get their due. Sweet build and keep updating your progress.

Project GatTagO

iTrader: (7)

Thanks GM High-Tech Performance!!!

http://www.gmhightechperformance.com..._gto_ls3_swap/

Andrew

Phillipm

iTrader: (2)

I was going to PM you to get an update but I figure why not let everyone get the information. I've got a 65 Olds Cutlass that has been lowered a long ways. So far that the ridetech arms had to be lengthened to get the pinion angle back up. I've C-notched the rear of the frame low. Haha.


Anyways I've got a huge tunnel in the car and I have all the room in the world to raise the trans however the front of my LS power steering pump is going to hit the steering box, headers will hit the floor blah blah. So, I of course have had a drive shaft vibration that I have fought with forever as well. In the end my working angle off the trans is 5 degrees because my shaft is up hill 2 degrees plus the 3 from the trans angle.

Question: is the CV joint still the answer in your mind (I know it's hard because you had the trans worked on too at the same time)? I read along your thread and you, like me have thought you fixed it to only later say man, I think I just hoped it was better and it really wasn't. Second, do you feel that the CF was really necessary or would aluminum have sufficed? I really appreciate your thread and everything you've done and documented.

Phillip

Project GatTagO

iTrader: (7)

Hey Phillip,

Thanks for the kind words.

I definitely think that the CV driveshaft is the way to go, especially with the earlier A-bodies that have an even longer wheel base than mine. Ideally, you would have CVs at both ends of the driveshaft, but that gets more expensive and requires even more custom parts.

I don't believe that the CF is mandatory, although lighter is always better. Aluminum should work fine, but I would consult with Frank at The DriveShaft Shop.

Also, if I had to do it again, I would use a non-plunging CV. There is no reason to have a plunging CV because the slip yoke works just like it did with conventional U-joints and provides the slip to accommodate the movement caused by the rear end. Using a non-plunging CV also simplifies the measuring procedure.

I really hope that Frank will eventually come up with a line of slip yokes and pinion yokes that are designed to work with CV joints. Every modern high performance rear drive cars use CV joints in the driveline and most are two piece, for even smoother running.

Andrew

Phillipm

iTrader: (2)

Awesome thank you for the update Andrew. I will give Frank a call.

Phillip

Phillipm

iTrader: (2)

Okay 1 more question.. Any reason you went with the longer MW Yoke vs. their shorter one? I always felt that the longer one just put more leverage on the pinion bearings..
-Phillip

Phillipm

iTrader: (2)

Sorry Andrew. Just looked up the part number and noticed you did go with the shorter yoke.. Doh!

Project GatTagO

iTrader: (7)

No worries. I actually called MW when I was getting the yoke and their tech told me that the short yoke was the stock length yoke. I forgot the reason why they made the long one...

Please keep me posted on your progress. I am eager to see how the CV driveshaft works for you. I really believe that this is proper solution for what seems to be a very common problem with lowered A-bodies.

Andrew

Project GatTagO

iTrader: (7)

There have been various discussion on several forums that I frequent regarding driveline vibrations, angles, etc...

In one of the posts, I made the comment that just about every modern, rear wheel drive, performance car uses CV joints for the driveshaft. We spent all kinds of stupid money to buy the latest engine, transmission, and suspension parts, but when it comes to our driveline components, we still use u-joints that date back to the 19th century. I have used a CV driveshaft with great success, but the optimal solution would be to use a driveshaft that uses a CV joint at both the transmission end and at the pinion. So I called Frank at The Driveshaft Shop to discuss this further and after telling him all this he starts to laugh. Then he proceeds to tell me how he just made a batch of pinion yokes for the Ford 9" and the Chevy 12 bolt rear ends that will accommodate a 108mm (Porsche 930 style) CV joint. He sent me the picture below:



That particular yoke is for the Ford 9" rear. What this means is that if someone wants the ultimate solution for a driveshaft, this is it. Using CVs at both ends of the driveshaft means that driveline angles become largely irrelevant. The CVs can accommodate up to 9 degrees of articulation and the front and rear angles operating don't have to match, be opposite, or be as small as possible.

Andrew

Jimbo1367

cha-chang

When I seen your car in the mag, I was like "thats Andrew's pride and joy. He finally got some ink"

Project GatTagO

iTrader: (7)

Thank you...but I've had ink several times before...going back to 2004. Although I love being in GM High Tech. I think my GTO is the first older car they have ever featured.

Andrew

gjestico

iTrader: (5)

Interesting. My buddies 2010 SRT Challenger uses rubber "donuts" for u-joints on the driveshaft. It is an IRS suspension though ; minimal driveshaft articulation.

Project GatTagO

iTrader: (7)

Yes, many modern cars with IRS use the rubber guibos in place of CV joints. However, if you look at the high end cars. many use CV joints, even with IRS.

Also, as you noted, cars that have a live axle can't really use the rubber guibos.

Andrew

Jimbo1367

good to know. I'll have to check it out