Dust Buster Race Car...help needed

[OnkelUdo]

Brand new member with a lot of questions because...my loose gathering of rabble may or may not be building a 1995 Pontiac Trans Sport with the Buick 3800 into a race car for one of the various budget endurance racing series...allegedly.

So if we were engaging in such folly we would need soooo much help.

Lots of questions to follow but since I am a GM-aphobe in spite of racing a 1994 Saturn SC2 for a year and a half so all this FWD, Domestic, plastic covered stuff is still a mystery to me. I am a mid-eighties Eurotrash guy.

First question is tires. We need to run lower profile tires and there are two approaches: stick with the 15's and go to a 205/50/15 or go to 16's and a similar profile. The advantage of the 15's is the 14% change in gearing. The concern in going with the 15's is what are we likely to confuse or break things by effectively changing the gearing by 14%? Competitive tires for this theoretical race series are readily available in this size but after finding out the alternator could not correctly charge without a 10V reference from the IP regulated voltage, I would not be surprised if the tranny would go into a limp home mode with that disparityl. ABS functionality is not a consideration.

Next, when installing the cage are there dangerous fuel, brake or electrical lines in areas along the sills in the following locations that are not readily visible (welding):

Front wheel wells.
Directly behind the B-pillars (at least on a b-pillar on a normal car).
42" to the rear of the same location so approximately 8" behind the second row.

Now suspension. We have little time and less budget to do suspension upgrades but the rear sway seems obvious. Are various redneck, no budget fixes appropriate such as: cutting coils, torching coils, swapping junk yard coils from another car, etc. Keep in mind...not a street car...it has to go around corners quickly. Any weird dangers with slotting the strut mount holes to maximize camber (did it on the Saturn and other cars I have helped with but can positively destroy and Alfa Romeo Milano).

Any issue running with the ABS essentially turned off. All my research says it acts as a normal fixed proportioning valve diagonal system.

What major weaknesses in the the engine, transmission, electrical systems, etc do we need to pay special attention to if we were to want to run a U-body in endurance racing where they will be at full throttle, full brake, rinse, repeat for 14 hours over two days...allegedly. A massive tranny cooler is in the works.

Does this tranny truly hold a gear if manually shifted or can it be forced to do so? Downshifting mid-corner is really bad juju.

Thanks,

OnkelUdo

[lemons bob]

This is BoB from over on the LeMons forum.

Since the A-Body and U-body are similiar I'll atleast pass on what we have learned from ours.

We just started running the 15's that you mentioned, the primwells lasted and worked ok at autobahn this summer. If you are going up look for the extra wide rims that were on some of the premiem larger sedans. They will easily be able to fit the 225 wide tires, if not not sure it would be worth the extra weight of the 16s.

The fuel and brake lines probably be exactly where you will want to weld. They should be very visable from the underside though so you should be able to stick something over it to protect it. The driverside should have brake and fuel lines so be extra careful, passenger will have brake and fuel vapor less dangerous but still be careful, the vapor line is easy to melt.

I've got the 2.8 so different engine, and my trans is the ancient 3 speed, but from talking to the guys who ran the century in Texas you need a transcooler. I grabbed a caddy one out of the junkyard that seems small but when draining it holds about 50,000 gallons(stupid thing leaked forever) I also have run Mobile Synthetic and the old 3 speed has run really well. I'd stick an oil cooler also but I just like to keep all my fluids cool.

Sticking the trans in 3 will not hold it there it will just stop it from wandering up to overdrive. Having driven auto in bunches of races it is really predictable and won't take long to figure out. When you brake going into a corner, or let off the gas it will shift up to the highest gear it can. As long as you keep it under 3/4 throttle through the corner it will stay in that gear, if you go full throttle it will downshift, but even if it is shifting you are not quite as powerless in the corner as if you had the clutch in.

As for suspension I would stay away from doing anything other than making sure that the shocks and struts are in good shape. Once you start doing suspension upgrades Judge phil may start have to consider putting you in B. Stock and untested you will be in c, if it runs reliably you have a chance to win C or IOE pretty easily first race.

[85_Ciera_Rebuild]

2.8...3 speed,

FWIW...when in lockup, there is VERY MINOR heat generated. Only time a AT-Cooler is needed is when running in non-lockup.

Hence, in everyday older vehicles, a new radiator is not needed for a long time, unless driving mostly in non-lockup mode (city driving)

3.8 Engine has always been a good engine, but timing chain will have to be changed out...interference engine.

[lemons bob]

Looking through notes again there are some 15x7 wheels out there too so if you can find them in things like some the olds 88s and its siblings you can go 225 r15 you know just to make tire choice more complicated.

[Duke George V]

The cars are quite nose-heavy, vans more so, so changes to the rear suspension should be limited to making sure the shocks are in good shape. Snap oversteer is a hell of a thing.

The van is several hundred pounds heavier than the car, and has the same transmission, so an external cooler is a must. An oil cooler might not be a bad idea, since heat soak is a concern with an all-iron engine.

The transmission is electronically-controlled, but can be manually shifted. You could leave the shifter in 2 most of the time, since the final drive makes second good for an indicated 75 mph.

Running some sort of ducting to the front brakes will go a long way to keeping them functional. One good hard stop from high speed is about all they're good for before they start fading.

[OnkelUdo]

Thanks for the help

This is BoB from over on the LeMons forum.

Since the A-Body and U-body are similiar I'll atleast pass on what we have learned from ours.

We just started running the 15's that you mentioned, the primwells lasted and worked ok at autobahn this summer. If you are going up look for the extra wide rims that were on some of the premiem larger sedans. They will easily be able to fit the 225 wide tires, if not not sure it would be worth the extra weight of the 16s.

The fuel and brake lines probably be exactly where you will want to weld. They should be very visable from the underside though so you should be able to stick something over it to protect it. The driverside should have brake and fuel lines so be extra careful, passenger will have brake and fuel vapor less dangerous but still be careful, the vapor line is easy to melt.

I've got the 2.8 so different engine, and my trans is the ancient 3 speed, but from talking to the guys who ran the century in Texas you need a transcooler. I grabbed a caddy one out of the junkyard that seems small but when draining it holds about 50,000 gallons(stupid thing leaked forever) I also have run Mobile Synthetic and the old 3 speed has run really well. I'd stick an oil cooler also but I just like to keep all my fluids cool.

Sticking the trans in 3 will not hold it there it will just stop it from wandering up to overdrive. Having driven auto in bunches of races it is really predictable and won't take long to figure out. When you brake going into a corner, or let off the gas it will shift up to the highest gear it can. As long as you keep it under 3/4 throttle through the corner it will stay in that gear, if you go full throttle it will downshift, but even if it is shifting you are not quite as powerless in the corner as if you had the clutch in.

As for suspension I would stay away from doing anything other than making sure that the shocks and struts are in good shape. Once you start doing suspension upgrades Judge phil may start have to consider putting you in B. Stock and untested you will be in c, if it runs reliably you have a chance to win C or IOE pretty easily first race.

Bob, your help is always appreciated on the "been there, done that" level.

The oil cooler is something we are not planning on currently but does the stock fuel pump have the capacity to push it without significant drop in flow?

Not too concerned about Judge Phil as he still has this vehicle on his list and I think minivans start in C until proven otherwise if we were prepping for LeMons as the first Dustbuster.

Transcoooler will either be the old condenser or one of the million available on the on HD vans and pickups that we have used as oil coolers on the Saturn. I also used a Caddy oil coller initially but managed to split one of the fittings from over torquing.

We have a 4 serviceable Rivals left from the Saturn so we plan to swap them over and buy two new ones.

I am picking up a 2005 Uplander beam axle with all attached brake hardware Monday. My teammate that you know is confident that the calipers will fit steel 15" wheels even if they have to shaved a bit.

Any idea if the assumptions I made on the ABS system are accurate...diagonal system with normal proportioning if the unit is non functional?

Let me know if you are interested in coming by for a build day. We start tomorrow with gutting, breaking fasteners free and re-torquing etc.

Thanks again,

Onkel Udo

[OnkelUdo]

Oddly, by my estimates, once gutted the van should be within about 150#'s of a Century form the same era.

As the brakes from our year match those available in the Firebird good brake compounds are available for the front. With my experience from the Saturn I can say that outrageously expensive pads from Porterfield or Carbotech can eliminate fade and even the EBC yellows we ran change the nature of the braking completely.

To 85_Ciera...was surprised to learn that the Series I is an interference engine. What are these pushrods I keep hearing about? Are those for moving the car around with engine off? Silly GM.

[lemons bob]

Oddly, by my estimates, once gutted the van should be within about 150#'s of a Century form the same era.

As the brakes from our year match those available in the Firebird good brake compounds are available for the front. With my experience from the Saturn I can say that outrageously expensive pads from Porterfield or Carbotech can eliminate fade and even the EBC yellows we ran change the nature of the braking completely.

To 85_Ciera...was surprised to learn that the Series I is an interference engine. What are these pushrods I keep hearing about? Are those for moving the car around with engine off? Silly GM.

Weight wise might be close but I bet the balance is even worse at being nose heavy after stripping. You'll have to eventually stick something in the back to even out the weight of the engine.

Another way to help the brakes is if you get wheels with good airflow. We recently got some alero wheels which are light and have lots of open space for heat to escape, available in 15 and 16.

I also am kind of surprised the 3.8 is an interference motor. the 60 degree ones aren't and also have the push rods, because then it gets a nice low rumble, especially after you simplify the exhaust from stock.

[OnkelUdo]

Weight wise might be close but I bet the balance is even worse at being nose heavy after stripping. You'll have to eventually stick something in the back to even out the weight of the engine.

Another way to help the brakes is if you get wheels with good airflow. We recently got some alero wheels which are light and have lots of open space for heat to escape, available in 15 and 16.

I also am kind of surprised the 3.8 is an interference motor. the 60 degree ones aren't and also have the push rods, because then it gets a nice low rumble, especially after you simplify the exhaust from stock.

Yeah, expecting the balance to be terrible. Putting the battery where the second row, outboard passenger seat is. After that we have joked about leaving two of the seats in the third row...might just do it even of it is only 60#'s.

The little research I have done certainly supports the claim of the 3800 being an interference motor though I am not sure why. The torque is excellent but the horsepower only moderate for its displacement.

We already have a "performance exhaust" thanks to the Chicago winters. Have not assessed the end-to-end condition yet but we will be cutting the cat out and using a bypass pipe. Gotta love ODBI.

[OnkelUdo]

The transmission is electronically-controlled, but can be manually shifted. You could leave the shifter in 2 most of the time, since the final drive makes second good for an indicated 75 mph.

Roughly 67 with the change in gearing by the much smaller diameter tires. Depending on our acceleration (not terrible ut not exciting) and cornering speeds (likely abysmal) this would mean the need for 3rd is only on the longer straights. Good to know.

[lemons bob]

Roughly 67 with the change in gearing by the much smaller diameter tires. Depending on our acceleration (not terrible ut not exciting) and cornering speeds (likely abysmal) this would mean the need for 3rd is only on the longer straights. Good to know.

These gm v6's in lemons tend to pull pretty well. The Torqueness of the engines tend to make them perform better than most people would expect when they look at the HP. You will probably find yourself needing 3rd a few times a lap at autobahn south alone. With the 3 speed we have a good 10mph more before having to shift and we still needed to shift into 3rd gear and with the 2.8s power band it actually was just as well to let it shift into 3rd before redlining in some spots to be easier and not really lose speed since it kind of peters out powerwise towards the redline anyway.

[85_Ciera_Rebuild]

I also am kind of surprised the 3.8 is an interference motor.

3.8 is an intereference engine, but I understand 3800 is not:

GM 3.8 and 3800

Bad luck with GM 3800 motor!

[babyivan]

3.8 is an intereference engine, but I understand 3800 is not:



Bad luck with GM 3800 motor!

HAHA, I'm a poster in that one.... pages 3 & 4! good ole BITOG

BTW, the 231 Buick engine (3.8/3800) is a great engine marred by a few flaws over the years... early on, the timing set used nylon teeth and later on, the plastic intake wreaked havoc!... pick your poison.

As far as interference.... they were ALL interference engines, regardless of generation/series!

[85_Ciera_Rebuild]

As far as interference.... they were ALL interference engines, regardless of generation/series!

Many FWD engines are, but clueless said: "I've broken the timing chain on on an '89 3800, that engine was non-interferance..."

He must have been LUCKY...

[babyivan]

Many FWD engines are, but clueless said: "I've broken the timing chain on on an '89 3800, that engine was non-interferance..."

He must have been LUCKY...

Lucky is what he was.... the 231 was an interference engine from beginning till end. There have been instances from owners of various interference engines that have skipped timing/snapped timing belts, what-have-you and not caused valve damage as rare as that may be (hence all the confusion surrounding interference damage)....
Ive read threads from people with NON-interference engines ("Yota's 4SFE, for example) having valve damage after a timing belt failure, so who really knows.