1990 Reatta Convertible w/ 3800 Series 3 SC swap (pics)

Just finished my latest swap. This time it involved swapping a 3800 Series 3 Supercharged V6 (w/ performance mods) into a 1990 Buick Reatta convertible. The OE Reatta 4T60 transmission had a performance rebuild done by Triple Edge Performance. OEM type Reatta engine and transmission mounts were used. The stock Reatta A/C compressor mount bracket had to be modified slightly for the A/C compressor to clear the supercharger belt and I had to custom make a bracket so the kickdown cable for the trans could be connected to the throttle body linkage (see pictures below for details). I built a 2.5" mandrel bent exhaust system for this car utilizing a Magnaflow muffler. The induction system is a true "cold air" system using cannibalized 3.5" ABS OE 99-up GM 4.3L fullsize truck induction tubing and a K&N filter located outside the engine compartment via the factory hole meant for the charcoal canister (which has been relocated to behind the left fog lamp). The stock Reatta ECM was retained to keep all electronic systems fully functional; this was made possible by a custom tune I made for this swap.

If you have any questions, please feel free to ask. Yes, it will boil the front tires at command now!

If you have any questions, please feel free to ask.

The first question that comes to mind is ... How much does something like this cost?

John F.

The first question that comes to mind is ... How much does something like this cost?

John F.

John, my labor rates and flat rate pricing structures are subject to change; so I hesitate to post any prices on a public forum due to the nature of this business. The price I would post today wouldn't be what I would have to charge, say 5 years from now, due to things like inflation. And I have run into this before - where I've had people contact me demanding services for prices I posted years ago on various public forums.

However, I would be happy to discuss today's current prices with you via PM or email.

Hope you can understand where I'm coming from.

-ryan

Ryan,

Thank you for your response. I do understand where you are coming from.

PM sent.

John F.

Ryan,

Very nicely done - and that is a collosal understatement. If I had to replace an engine I would consider doing this. Especially good to know that ECM and instrumentation compatibility can be retained.

Incidentally, is the subject vehicle a select 60? It is the right color and has the white 16" wheels. I'd say that makes it an ultra-select edition.

KDirk

Ryan,

Very nicely done - and that is a collosal understatement. If I had to replace an engine I would consider doing this. Especially good to know that ECM and instrumentation compatibility can be retained.

Incidentally, is the subject vehicle a select 60? It is the right color and has the white 16" wheels. I'd say that makes it an ultra-select edition.

KDirk

How can we determine if it is a "select 60"?

Concerning the swap, there were a few more modifications that were required that I forgot to mention in the original posting.

1) I had to modify the factory Reatta dog bone engine mount bracket to extend its height by about 1" to accommodate the 1" shorter deck height of the 3800 Series 3 engine (Series 2 is the same in this respect) so the factory dog bone mount could be reused.

2) I had to modify and use a Series 2 3800 GM C/H body power steering pressure line and used it to replace the factory Reatta's power steering pressure line due to the fact that the power steering pump on the Series 2 & 3 engines mounts down low (below the alternator) on these engines. The return line was just cut off and connected to the pump using a hose, so that was the easy part.

3) Since this was a Series 3 engine, it came with a returnless fuel rail. I cannibalized a Series 2 SC's fuel rail for the regulator and, with the use of a flaring tool, got it mated up to some AN fittings so I could connect the regulator (which bolts to the left strut tower) to the factory Reatta fuel lines and then to the fuel rail via a braided -6 AN line. One thing I noticed about the factory Reatta fuel lines, at least on this car, was that they were both nylon 5/16" diameter lines (same size for both the return and supply). Normally GM cars have a 3/8" diameter line for the supply but I don't know why GM only used 5/16" on this car. I have a concern that the 5/16" line won't be big enough for high performance builds but it was adequate for this particular swap which is probably making around 300 crank hp or so.\

Ryan,

A 1990 select 60 was a special edition convertible as follows:

All white exterior with black rub moldings and no pinstripe. Wheels were 16"*7" alloy with white painted finish. White vinyl convertible top.

Interior was flame red carpet and dash with white leather seats and door panels. Carpet and speaker grille inlays were flame red. Had 1991 style center console with retractable cup holder.

On further review, I see this car has white rub moldings, not black. So, either it isn't a select 60 after all, or someone repainted the rub moldings to white. I can't see the interior at all so cannot use that as a point of reference. It does have 1991 style wheels, which are readily identifiably as different from the stock wheels used in 1990 (15" 5 spoke machined aluminum design).

After reading your most recent post, I have the utmost respect for your fabrication and modding skills. It is the small details that are easily overlooked in planning something like this swap. Having the knowledge and ability to think of fixes on the fly is a gift not many are endowed with.

KDirk

Ryan,

A 1990 select 60 was a special edition convertible as follows:

All white exterior with black rub moldings and no pinstripe. Wheels were 16"*7" alloy with white painted finish. White vinyl convertible top.

Interior was flame red carpet and dash with white leather seats and door panels. Carpet and speaker grille inlays were flame red. Had 1991 style center console with retractable cup holder.

On further review, I see this car has white rub moldings, not black. So, either it isn't a select 60 after all, or someone repainted the rub moldings to white. I can't see the interior at all so cannot use that as a point of reference. It does have 1991 style wheels, which are readily identifiably as different from the stock wheels used in 1990 (15" 5 spoke machined aluminum design).

After reading your most recent post, I have the utmost respect for your fabrication and modding skills. It is the small details that are easily overlooked in planning something like this swap. Having the knowledge and ability to think of fixes on the fly is a gift not many are endowed with.

KDirk

Thanks for the kind words.

I do know this car was repainted at some point. It was originally white as the underbody color suggests, but it is obvious it was repainted by looking closely at some things I could see on the body and door panels. The new color is white with some pearl in it which the photo can't really show. The interior is "red" but I didn't recall seeing any retractable cup holder or carpet and speaker grille inlays. Of course I didn't know what to look for when the car was still here so I could be wrong.

What's the extra HP do to the cowl shake?

What's the extra HP do to the cowl shake?

What is cowl shake? Are you talking about the car body buffeting you feel when you hit bumps in road that is due to it being a convertible?

Yes. Body flex was always an issue with the Reatta convertible and probably figured in to the decision to end production. Not sure if Barney ever calculated the percentage of convertibles produced that were not deemed fit to be sold to the public because of it. Be interesting to see how that compares to other models of the era like the Allante, Eldorado, etc.

Brings the old stories of the legendary Sunbeam Tiger to mind.

Gobs of new found HP can be fun until something breaks. If you harden the tranny, what's next to go?

Yes. Body flex was always an issue with the Reatta convertible and probably figured in to the decision to end production. Not sure if Barney ever calculated the percentage of convertibles produced that were not deemed fit to be sold to the public because of it. Be interesting to see how that compares to other models of the era like the Allante, Eldorado, etc.

Brings the old stories of the legendary Sunbeam Tiger to mind.

Gobs of new found HP can be fun until something breaks. If you harden the tranny, what's next to go?

The only time I noticed the "cowl shake" was when hitting road bumps. The increased power level the new engine brought into the car didn't seem to have any impact on that.

Concerning how much more flex the added power would put into the body; I don't think it is going to be a concern UNLESS one were to run drag slicks on such a car. If you ran slicks and did a lot of racing, I might worry about it. But for a street driver w/o slicks, I don't think I would be too concerned.

I didn't know there even was a Series III supercharged 3.8. In the interest of getting a free education, what years and models were they offered? Does anyone know? I'd also be interested in learning what they were rated stock for HP and torque. I had a 240 HP supercharged '98 Regal GS and found it to be very hot. I think it would be a perfect engine for the Reatta. I understand that the weak point in retrofitting them is the transmission and the later transmission can't be made compatible with the Reatta electronics. As D-A-N-I-E-L has found in fitting a series I to a hardened transmission, it still couldn't handle the extra HP. I hope this setup works. Please keep us posted as I am very interested in how this works out.

I didn't know there even was a Series III supercharged 3.8. In the interest of getting a free education' date=' what years and models were they offered? Does anyone know? I'd also be interested in learning what they were rated stock for HP and torque. I had a 240 HP supercharged '98 Regal GS and found it to be very hot. I think it would be a perfect engine for the Reatta. I understand that the weak point in retrofitting them is the transmission and the later transmission can't be made compatible with the Reatta electronics. As D-A-N-I-E-L has found in fitting a series I to a hardened transmission, it still couldn't handle the extra HP. I hope this setup works. Please keep us posted as I am very interested in how this works out.[/quote']

The 3800 Series 3 SC L32 engine was offered in select 2004-2008 FWD cars. They were rated at 260hp and 280tq; the added 20hp over the Series 2 SC L67 engines could be attributed to a better M90 supercharger design (Series 3 M90 blowers are known as GEN V blowers; whereas Series 2 M90 blowers are known as GEN III blowers).

Most 3800 Series 3 engines have powdered metal connecting rods (vs. the cast rods used in Series 2 engines). I say "most" because all of the Series 3 SC L32 engines produced for use in 2004 model year cars I've taken apart still had cast rods in them. All of the 2005-newer model year L32 engines I've taken apart had the new design powdered metal rods. There is some debate as to which rod is stronger (cast vs. powdered metal), but most of the evidence I've seen over the years suggests the cast rods are actually stronger.

All 3800 Series 3 engines (N/A and SC) have returnless fuel rails and use a drive-by-wire throttle control system. Adapter plates are available to allow you to bolt a cable-op throttle body to the Series 3 engines so you can use older computer systems to run them. I do NOT recommend using a Series 3 PCM in any swap due to some limitations with those systems relating to the restricted ability of properly programming them to work in swap applications.

Concerning the strength of a 440T4/4T60 auto transmission, I do not think they are suitable to use for any build that is going to see competition use. I think a proper performance build to one of these transmissions can make it hold up to a reasonable service life in a street application that sees occasional performance use. But if you are going to do a lot of racing, I think you would at least want a 4T60-E like what came in the 91 Reattas stock. The 4T60-E can accept many of the same upgraded hard parts made for the more modern 4T65-E. That having been said, the 4T60-E and the 4T65-E both still have their limitations concerning power handling. My trans builder is currently doing durability testing using the Cadillac 4T80-E attached to a 3800 Series 2 Turbocharged V6 in his Grand Prix, and it looks like that might be the way to go if you want the strongest FWD GM transmission you can get.

For those of you who don't have a 4T60-E trans, you can still use and install one if you get some kind of stand-alone transmission control module. If you are going to go the stand-alone transmission control route, then that opens up the option of using a 4T65-E or 4T80-E transmission as well. Unfortunately, the 1991 Reatta PCM, even though it is capable of controlling a 4T60-E, can't properly control a 4T65-E or 4T80-E.

I am so intrigued with the ramifications this swap I have gone car shopping {test driven} several Series III cars. First, I'm surprised this thread hasn't drawn more interest and second---I'm looking for the right donner car!

It should be noted that you can have a Series 2's GEN III blower housing ported out to improve its efficiency and gain that 20hp advantage the Series 3 Gen V gives you; or you could just install the Gen V blower (along with matching lower intake) onto a Series 2 engine.

Thank you for the quick reply. I have put $ down on a 37,000 mile 1997 GTP. Very clean, one owner----hit hard in rear. I will post photos when the car is unloaded Saturday.

I have put $ down on a 37,000 mile 1997 GTP.

A rare find indeed.

SP, do you know if the supercharger off of a 97 GTP would be a direct fit on the 3.8 in a Reatta? Reason I ask, is there's a lady in my town trying to sell just the charger and intake off of a 97.

SP, do you know if the supercharger off of a 97 GTP would be a direct fit on the 3.8 in a Reatta? Reason I ask, is there's a lady in my town trying to sell just the charger and intake off of a 97.

No.

Thanks Daniel!! I'm not to sure about anything on these 3.8's. I just saw the charger for sale and was curious. (And, I highly doubt the wife would let me have some fun if it did fit!!!)

The Series 2 or 3 supercharger will not physically fit on the stock (Series 1) 3800 engine that came in the Reattas. However, if you got a supercharger and all the related hardware off of a 92-95 3800 Series 1 SC engine, you could put that on your stock Reatta engine. I know people have done it before.

The Series 2 or 3 supercharger will not physically fit on the stock (Series 1) 3800 engine that came in the Reattas. However, if you got a supercharger and all the related hardware off of a 92-95 3800 Series 1 SC engine, you could put that on your stock Reatta engine. I know people have done it before.

Thanks for the info!

The Series 2 or 3 supercharger will not physically fit on the stock (Series 1) 3800 engine that came in the Reattas. However, if you got a supercharger and all the related hardware off of a 92-95 3800 Series 1 SC engine, you could put that on your stock Reatta engine. I know people have done it before.

It require way too much modification to do economically. With the series one it is always cheaper and less time consuming to swap the whole motor, as phillip found out a long time ago.

With the series one it is always cheaper and less time consuming to swap the whole motor, as phillip found out a long time ago.

I agree.

Concerning trannys I remeber something about the general having to dial back the supercharged 3800 in Grand Prixes on shifts to keep from scattering transmissions & pretty sure those were 4T65Es. Something about the original 440T4 being designed for the 2.8 and being at its design limits along side a 3800.

Concerning trannys I remeber something about the general having to dial back the supercharged 3800 in Grand Prixes on shifts to keep from scattering transmissions & pretty sure those were 4T65Es. Something about the original 440T4 being designed for the 2.8 and being at its design limits along side a 3800.

What you are describing is known as torque management. The factory 3800 SC PCM retards timing during the transmission shifts to cut engine power to help extend transmission service life. This also has the added benefit of reducing the likelihood of detonation occurring during the upshift = sudden load increase on the engine. As far as I can tell, working torque management protocols were first used with the 3800 SC engines in 1994 model year computer systems.

Interestingly enough, the stock 1990 Reatta 3800 ECM has some torque management logic in it that I found buried in the factory code. But I couldn't seem to get it working with the limited amount of time I had tuning this latest Reatta swap. If the 1990 LN3 ECM has it, then I would have to say it probably also exists in all later 3800 ECMs and PCMs as well. Whether or not you can get it working in anything 1993 model year or older is unknown at this point.

Contrary to popular belief, disabling torque management does not result in a noticeable increase in performance. The reason why is because it only takes a good working automatic transmission a fraction of a second to complete a shift. And allowing the engine to produce full power that extra fraction of a second isn't going to result in any significant performance gains because we are not talking about a huge amount of time it is actually cutting engine power.