superchargers

[RatReatta]

i see in a bunch of peoples "signatures" that they have supercharged reattas. i was thinking about how i would love to try a supercharger but i dont even know where to begin or if it is even a good idea <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">

Don B. Maker of the first street legal Super Charged Reatta

</div></div>

with your 'chargers where abouts do you place speedwise? i already know that i drive too fast and that a supercharger would probably be too much temptation but its something i want to try, i think its maybe a teenage guy thing but i get bored driving at anything under 70mph. please help

[padgett]

Possible but not easy. Where you want to start is with the entire powertrain including computer out of a low milage, little old lady owned 92-93 Series I supercharged Park Avenue or somesuch.

The only difficult part is the computer data stream feeding the dash and at least you are closer than Greg.

[RatReatta]

what do you mean "at least you are closer than greg? the best luck thing i guess is that my town "Palm Coast" the average age is somewhere over 60 so buicks are in no short supply, after i locate a suitable donor car how should i approach everything? do you know a good daytona area shop fo such a thing?

[Guest Greg Ross]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> "at least you are closer than greg? </div></div>

This pertains to me, Padgett has assisted me with major 'moral Support" and the programming to make my S/C 5-Spd. a reality. The fact that I reside in PEI, Canada, a mere couple of thousand miles away from Orlando has everything to do with the comment.

[RatReatta]

right, i just havent been on long enough to quite catch the references. you got yours done by gutting a park avenue?

[Don B.]

I found a Park Ave Ultra in a salavge yard.

Pull the motor and trans though I did not

use the trans. Put it in my Reatta changed

all the sensors and fuel pump. Some other mods too.

The car was running 15's in the 1/4 mile.

But you have to run Premium fuel all the time.

[Guest tempest68]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">...i get bored driving at anything under 70mph... </div></div>

If you like top-end, then wouldnt a turbo be better? Turbos typically like to wind up higher in the RPM range and generally do well at higher speeds. Superchargers are better at grunt off the line upto 60-70ish.

I love my GTP when racing from a stop, but a Suby-WRX or Mitsu-EVO can put a hurt on me if we go from a 60 MPH roll.

[padgett]

Boost is boost. A supercharger can drain more direct power than a turbo but reponse is far better than a blow through and somewhat better than a leading throttle plate but does not have all of the plumbing issues. With the right controls either can provide as much boost at any speed that you want.

The nice thing about starting with an L-67 or other supercharged 3800 is that it is an integrated package with beefed bottom end as well as top.

[Guest Greg Ross]

Rat,

To answer your question;

Engine-Goodwrench Remanufactured, then disassembled and balanced crankshaft and rods. This was path of least resistance to be able to bolt a modified flywheel onto the back of it.

Transmission-Getrag Model 284 as used in V-8 Fieros. Came from 91-93 Grand Prix, Lumina, Cutlass with the 3.4L DOHC V-6. Bought as Salvage and then had it rebuilt through GM.

Electronics modifications were necessary to allow the ECM to forget about managing an automatic Transmission. Not certain about adding on a Park Ave. ECM just to run the engine, Sahein (Rob) has gone that way and I donèt know what the integration issues are. To retain the Data Screensé Diagnostics capabilities I liked the idea better of modifying the ECM to manage Boost, Fuel, Air,for the supercharged engine.

As far as I know mine is the one and only 5-Speed on the road.

[2seater]

Greg,(plus others), and I have discussed the pros and cons of turbochargers or superchargers, and each has it's strengths and weaknesses. The S/C would seem to have the advantage of quicker response time, particularly at low speed, and that is somewhat true. I found my turbo setup spooled up more quickly than I wanted, so I turned the boost down to slow the power delivery. I always looked at this as a bit of an advantage with a relatively low traction fwd and a transaxle which is probably marginal if hot rodded too hard. The turbo is still responsive enough to hit full boost during the time it takes to downshift at highway speed. The s/c also has the advantage of being somewhat simpler to install, since GM has already done the work for you, you just have to buy the parts. It should be possible to retrofit the Series I supercharger to the stock 3800 in the car now, but there would be additional parts to be relocated besides the 'charger itself. The advantage of changing the whole engine, would be the possible greater strength of the engine it was designed for, although I do not know of any evidence this is true, on the Series I that is. The Series II is a different animal and does have several improvements. The turbocharger requires a lot of hand fabricated piping to make it work, and both the S/C and turbo have issues with ECM control of the timing and fuel flow, since both will produce more air flow than the stock MAF and ECM are programmed to read, plus the ECM has no boost sensing ability. A lot of what you want to do has to be done through "cut and try", since there is only a small pool of people that have done either one. I seem to be the only turbocharged Reatta, which does work well, but there are still issues to deal with, particularly engine knock and spark retard. As for driving fast, the car actually does seem to like running at speed around the engine torque peak rpm, or in the 70-75 mph range in the '90's and earlier engines. It will run a lot faster, it just isn't a rocket getting there.

[Guest Greg Ross]

Now from the GET REAL Dept.

I have, what I consider to be a pretty able mechanical aptitude and a reasonable understanding of the ECM control/interface functions. I would say I spent (part time) 3 months figuring out what parts could or might work to do my Manual Tranny conversion and then another 3 months (part time) on what it would take to get the 3800 Series I engine organized. (No S/C yet)

I must have done reasonably well because it only took 7 days to actually do the new engine/ tranny swap (including 2 days of head scratching over clutch function issues) This phase probably involved 200 manhours of actual physical work, including fabrication of the pedal set, fabrication of misc. clutch, motor/ tranny mount, cruise control bracket, etc. etc.

I opted to pull the engine when I installed the S/C to send the Tranny away for remanufacture. (1 week turnaround) The S/C install involved (for me) replacing the fuel tank/ fuel pump, fuel lines and fabrication of high pressure flex lines with scrounged end fittings to suit the fuel line harness and the S/C fuel rail. This venture, probably another 50 manhours.

To think seriously about this type of modification you've got to rationalize your own capabilities, what you can scrounge and ultimately you'll have to pay for.

Last Summer while in Flint at the BCA with Betsy Blue the hood was up alot. If I heard it once I heard it 25 times "Thats' just exactly what I was going to do"!!! I would hear from passers'by. They would stand and ooh and aah and I was super proud to be able to share what I'd done and how I'd gone about it. Round about the last day we were there a fellow came by and said he was having a lot of trouble getting his S/C Reatta running. Some wizzard had given him a bumn steer about how to install a 3800 Series II S/C engine. Charged him "whatever" to make a crossover harness to adapt the Series II PCM to the original ECM wiring harness and of course it would not work (late model Series II PCM programming speaks a different language)All I could do was sympathize and suggest the only option I knew of, replace all the sensors with Series I type and revert to the original ECM. Control of Boost has to be dealt with but at least you can be running and pretty darn good too. But I digress

So, how commited are you, and more important, can you afford to start this project?

[Bob]

Bravo, good speech. I was getting real sick and tired of hearing all these people building supercharged reatta's. They look on eBay, think about buying an engine, and think they can pop it right in their daily driver in one weekend. And they would not need the extra power if they would just take out all their extra weight from their trunk rattlers and other "pimp" mods.

There are alot of reatta owners who would like to do what you accomplished. Some might be seriously thinking about it (not bragging about it), and maybe another performance car might show up down the road.

For the supercharged, turbocharged and V8 cars that do exist that were built by the respected individuals on this forum, I would like to make a website to showcase the cars and the work put in to them (not a how to).

email me at bob@techturds.com if you are interested.

[Guest Buick Mike]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Boost is boost. </div></div>

Not really.

Assuming equal boost, the turbo will deliver more power due to much less parasitic loss. Additionally, the turbo will develop peak boost much sooner than the supercharger so your torque curve will be flatter.

Not assuming equal boost, turbochargers are capable of much higher boost levels than superchargers.

I like turbos.

Mike

[Guest Greg Ross]

Buick Mike,

How is it I never noticed you posting while I was a resident in sunny south Louisiana the past couple of years. Houma, La working on Exxon Mobil Canada projects.

[Guest Buick Mike]

Can't answer that. Maybe it's because I don't post all that often... or don't usually have anything interesting to say... or who knows.

Do they still do windsurfing on PEI? I was going to go there once, but ended up going to Aruba instead. PEI sounded like a great place, though.

Mike

[padgett]

As for the "boost is boost", yes a turbo can achieve 45 psi of boost. None of our engines are going to live with anything over 15 (and I would keep it under 9 with pump gas).

Whether you get fast response has more to do with whether a blow through (slow spooling) or draw through (fast spooling) than whether crank or exhaust driven.

GM had a reason for going to crank driven superchargers (Eaton M62) from the turbos of the eighties and on a street car can make all the power desired in a compact package. Of course it may have just been easier to handle from a production line standpoint.

ps you pay for a turbo also, it is just in increased backpressure (free EGR) in the exhaust.

[2seater]

I agree the total power potential of the turbo is greater, and the increased backpressure seems to be overcome pretty easily. There are definitely plumbing issues to deal with and heat radiation has to be considered carefully. The one thing I do like about mine is that it is sorta self-propagating. Boost equals more exhaust flow which in turn spins the turbine and compressor faster, which gives more boost etc.. I also agree with Padgett that the maximum the stock system can handle can be achieved with either system. I also believe the supercharger has better air distribution inside the intake, whereas the increased air flow from the turbo inside the stock intake accentuates an unbalanced situation. I watch with interest one of the IHRA drag classes that allows nitrous, s/c or turbo's. One year one system will be faster, the next another will dominate. It seems boost in any form can give you the thrill you are looking for, but they can always be improved through careful testing and modifying.

[Rattaboy]

The Toyota Supra of not too many years past had two turbochargers. One was to spool up quick to eliminate the lag associated with turbos of the time. Guess it was a real war hoss. The engine used was their inline six which was a good torque motor to start with.