BBR's 83GT - 552 BBF version 3.0 (at least)

[BBR]

Fiddled with it last Saturday. Decided to go up on the primaries and down on the secondaries to reduce the spread and maybe improve drivability a little. The AFR at cruise was 15+, but it had a little stutter if you eased into the throttle. Upping the mains dropped cruise AFR a little to the 14 flat range, but eliminated the little stutter. This thing is getting good. Way better than the 950 ever was and way better than I ever expected this Dominator to be.

Current tune:
TSJ .052
PVCR pri only .063
3.5 Primary PV (no sec.)
EB .028
IJ .040
MJ 92, 97
IAB .065
MAB .028

Drove it for the first time with the bags. Rides real nice and the back tires do not rub when hitting dips with a full tank of gas like they used to.

[BBR]

Next up!

Manual brake conversion. These cars come from the factory with the small bore (0.827" or 21 mm) master cylinder, so it should not be too big of a deal to switch. Besides at 7.5", my car does not really make enough vacuum to operate them properly.



The brakes currently work ok. Slowing from 120+ mph at the track has never really been an issue even with the small 10" discs and 9" drums. What *is* an issue is access to the plugs and valve cover bolts on that side. I'm just tired of it being so hard to work on over there.

[Beagle]

I always wondered why you were messing with power boosters on this car. I'll have enough vacuum and still thinking about removing the booster, the car doesn't weigh all that much.

[Deaf Bob]

Next up!

Manual brake conversion. These cars come from the factory with the small bore (0.827" or 21 mm) master cylinder, so it should not be too big of a deal to switch. Besides at 7.5", my car does not really make enough vacuum to operate them properly.



The brakes currently work ok. Slowing from 120+ mph at the track has never really been an issue even with the small 10" discs and 9" drums. What *is* an issue is access to the plugs and valve cover bolts on that side. I'm just tired of it being so hard to work on over there.

We remove all boosters on derby cars.. Most of them are junk anyway.. But the main reason is to clear the headers going up..
Your part is a pretty piece like we made for our's.. Caddys are wedge shaped, thicker up top..
Don't know why, but firewall flexes more with those types of conversions.. When done, you might be able to see if it flexes by watching the master cyl.. as you press, the master cyl might go up.. ..only reason I say anything is brake line failure due to flex..
Should you have the looped line, you might be ok.. Never ran a car long enough to have brake line fail..

[STINEY]

Be sure to change the pedal ratio too. Often that is a missed item on a manual conversion, and it is actually the main part of a good feel and effective manual setup.


See the unpainted hole just to the left of the green paint can? That is the original Power Brake Pedal pivot point. Move the pedal pivot down an inch to the lower hole like this picture.



This picture doesn't show it very well at all, but the master cylinder pushrod mounting pin on the arm has been moved UPWARDS two inches on the arm, in order to improve pedal ratio. This is how the OEMs did it. I filled in the original pin hole with weld and ground it smooth, so it is really hard to see here.



That, plus your mounting block (mine is natural aluminum in the above pictures) equals a easy effective manual conversion. I made a new pushrod by welding the one from the booster to the one from the pedal arm, after measuring for the correct length. Be sure to not make it too long, or the master will not close all the way. Leave an 1/8" - 3/16" of "slop" in there.

[BBR]

Stiney for the win..... but I do have to ask.... have you actually driven yours since the conversion?

[STINEY]

No, but I have stopped it from 50 mph five times.

(I've converted several cars from a few OEMs, the method is the same on them all. The others logged many thousands of miles.)

[BBR]

10-4 just razzin ya a bit.

[STINEY]

No problemo. I deserve it!

(I really did stop 5 times with it. Towed it around the block to try the brakes, so it was actually stopping the tow vehicle too)

[SuperBuickGuy]

Stiney for the win..... but I do have to ask.... have you actually driven yours since the conversion?

that sounds like something I would have said

[BBR]

SW wind blowing 25-30. Sounds like a good night to go to the track.

Much much more favorable than last time's 20+mph SE wind.

[squirrel]

Nasty thunderstorm over Dan's house, I'm not supposed to go get him for a few hours...by then the storm will be over my house. And it will follow us up to Tucson.

[BBR]

What a fun night at the track! Car was ridiculously consistent for the first three runs in spite of me changing shock settings and air bag pressures. It ran 11.10, 11.09 and 11.09. The 60 foots were 1.53's. No matter what I did, it 60'd the same. We joked that I should have run in the gambler's race they were running in conjunction with TNT. Finally on the last pass, after jetting up the secondaries 2 sizes and bumping the timing 2 degrees, I was rewarded with my first 10 second slip on Amarillo. It went 10.98 @ 123.6 and I was doing backflips inside my car! DA last night was 6500 and the wind was pretty calm.

Later, when hooking up the trailer and when driving home I could hear a strange noise coming from the bell housing area. Kind of a ringing sound. I jacked it up today to find ALL 4 converter bolts loose! Real loose! Tightened those up and all is well again. I'm just glad it was not a busted flexplate or worse, a converter.

The 10.99 second monkey is now off my back and the 10.50 monkey takes it's place. lol

[squirrel]

way to go! I hope you loctited the nuts.....

And watch out for those monkeys.

[Beagle]

Congratulations James!! I bet the interior is thrashed from you doing the blender inside it.