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Discussion Starter · #1 ·
Hey everybody, how's it going?
New to the forum here, but not to the forum environment, so hopefully getting involved here won't be too difficult.
Here's what I have and what the plans are for it.

I just bought a 1998 Bonneville SSE from my brother's girlfriend. It is fully loaded and in real nice shape other than she recently lost oil pressure on the highway, and the engine is knocking bad and locks up when warm. Paid 500 for it, so I think I'm doing alright so far.

I gonna fix it in the spring when the other cars come out of the garage from winter hibernation, so I've got a while to find some deals on parts.

The plan is to find the engine, tranny, harness, and computer from a supercharged car, and sell the tranny from my car.

My questions are 1. is this all that I need to complete the swap? I've been doing some reading and it looks like it is.
and 2. can I get these parts from any car with that engine (Regal GS, GTP, SSEi, etc.) and mix match them, or do I need some of them specifically from a Bonneville? I imagine the engine and trans should all be the same at least.

Thanks, any help is appreciated, and I look forward to being part of the 3800 community.
 

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I believe the tranny is specific to the ssei/ultras, the case of tranny is different for the mounts. I would reuse the existing tranny if there is nothing wrong with it. You can upgrade to a HD differential pretty easy while the tranny is still in the car but it takes a lot to break the stock differential so it is not a must.

The pulley system on the front of the motor is also different between GTP and Bonneville's but those can be bolted on if you have all the right pieces. Probable easiest if you find a donor Bonneville or Buick Ultra. 2000 up Bonneville's are different than 1999 and older. I would recommend keeping your harness, PCM and all the sensors from your stock motor and swap them onto donor motor. You can than get your PCM reflashed by one of the many vendors for the supercharged swap.

The flywheel to torque converter bolt pattern is also different between supercharged and normally aspirated motors.

That should give you some stuff to look into and I'm sure you'll get a lot more advice.
 

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Discussion Starter · #3 · (Edited)
Alright, thanks.
The tranny has almost 190,000 miles on it, but is still shifting good.
Is the stock SSE tranny good for the power of the S/C 3800?
It would not be beaten much, but it needs to be reliable.
Anyone have any experience with transmission compatibility from other models?

By your post I assume that the electrical is the same other than the tune in the computer? would the stock harness need modified to hook up the S/C engine?

And by pulley system, you just mean all the accessories, not the pulley setup on the supercharger right? If so, swapping them to the new motor wont be an issue.
 

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Transmission guts are the same, the only difference between NA and Supercharged is the differential and driver CV axle. 4t65 is NA and 4t65HD is supercharged. At 190,000 miles the 4th gear splined shaft will be almost stripped. Search here for 4th shaft here or go to Hard Parts for more info on tranny. I just rebuilt my tranny at 170,000 miles. My tranny still worked but one of the electrical shift solenoids went bad. I did a complete overhaul while it was out.

Pulley's or accessory belt system is slightly different, again because of the mounting, the supercharger and pulley are the same on all the cars.
 

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How's it going... Bonnie guru here for ya.

The trans is the same trans as you'd find in a W body and other 3800 cars except you have to make sure of one thing. That is has the three bolt mount webbing and structure on the back driverside of the trans casing. Some of the W bodies don't because they don't use it as part of the mounting.

Here's a pic of what some of the W bodies look like.


Here's the webbing/bolt holes you need. Interesting is that many W bodies got these casings as well.


My suggest would be to check for the webbing and not to discard a potential donor until it's checked. The NA trans and SC 4T65e's really aren't that much different. All the parts are the same except the drive/driven gears the output shaft and differential with it's cover. If you put the diff/output shaft and diff cover on a NA trans you'd have 3.29 gears instead of the HD trans 2.93 gearing. In a Bonneville it's pretty nice as it helps you get the weight rolling.

Engine, while the Bonneville has a different SC tensioner and bracket for the front SC pullies, you can use a W body one. it won't be as clean looking, but the H body (Bonneville) doesn't relay on it for a dogbone mount. All the Bonne mounts are down low and out of the way. You can use the W body one w/o worries if that's the donor you get. You'll just have a hole for a dogbone that won't be there. The W body is a little tighter under the hood on room and the Bonneville tensioner has been used in W's for better belt wrap. Overall though..it should'nt be a concern.

Make sure your flex and torque converter have the same bolt pattern, our 3800's use one of two. 245mm or 258mm. Mostly the 245 was certain NA motors.

Swap the exhaust manifold in the rear and you should be all set.
 

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Discussion Starter · #6 ·
Thanks BillBoost37, that is exactly the transmission information I need.
Would a different ratio differential cause any driveability issues, or just different speed and torque multiplication?

So.... if the transmission is correct, then the engine and transmission from a GTP, Regal, etc should basically bolt in with a new driver side CV axle. Then I should be able to piece together the serpentine setup using components from the 2 engines, correct?

What about electronics? Will my factory harness hook up to the GTP engine and transmission, or do I need a new harness? Then all that is left is to get the computer reflashed.
 

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Hey Tony, another Bonneville expert to chime in.

IF you decide to change the trans, then you will need PCM programming to make the trans shift properly, (easy).. and just for clarification, you would need a new PASSENGER side axle if you get a HD trans

speaking of that, your current harness will work, with some adaptations for the BBV,BCS and relocating the MAP sensor. This is simple, and there is also a harness adapter that one of the vendors sell to make everything easy. The Final thing is to get the PCM programmed with the L67 Bin File and Trans settings, so the car knows what i happening under the hood.

There have been alot of people that have swapped engines in the W bodies, most dont do it in the H body but its just as simple and easy.

any other questions ask awau
 

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Discussion Starter · #8 ·
What is the motor/trans mount setup? Two on the tranny (front and back) and one motor mount on the front (or passenger side) of motor?

All of mine (if good or buy new ones for my car) should bolt right to the any 3800 series II and Tranny (assuming the case is correct) right?

And to make sure, between my car and a donor engine, the serpentine setup should be all there?

Finally, would the harness modification basically be adding a few pins and connectors onto the computer connector and extending the MAP wiring?

Thanks for the help and bear with me. Trying to get this as close to 100% figured out and budgeted as I can before spending any money.

What's the best way of going about getting my computer reflashed?
 

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T...

You are on the money with the mounts. Although the L67 (SC) passenger side mount is different than the L36 (NA). It's a slight difference that most of us wouldn't be able to tell unless we put them side by side. (I learned that one by bending a pulley :8). Should be pretty easy to find at a junkyard though. I haven't ever had the need to check the passenger side lower rear mount (dog bone) between the NA and SC motors. You might find a difference in part of the bracket, but I think they cross over.

The wiring, if you get the kit, you'll connect two wires for the BCS connector and put an extender harness in place for the MAP sensor. Thinking off the cuff here, I have a 98 harness sitting in my garage that I had on my car at one point. Only thing is it uses the L32 map sensor which I have a spare of and could send with the harness if you wanted to go that route. Your lowest cost and easiest route though is to add the kit to your current harness.

Only other thing that might trip you up is the fuel lines. On our year Bonne's they come from behind the passenger strut tower and any change from the factory fuel rail for your model will allow them to kink and maybe give you trouble. I'd suggest picking up Swagelok adapters and then some AN stuff with the proper connections.

Got most of the parts from Summit. they seemed to have the best prices.
To go from hard metal lines to fuel rails.
Swagelok for the 5/16" tube adapter to -6AN is part # SS-500-6-6AN
Swagelok for the 3/8" tube adapter to -6AN is part # SS-600-6-6AN
EAR-981506ERL Fitting, Coupler, Straight, Male -6 AN to Male -6 AN, Aluminum, Blue, Each 2 $5.90
SUM-220687 Fitting, Hose End, 90 Degree, -6 AN Hose to Female -6 AN, Aluminum, Red/Blue Anodized, Each 2 $25.90
SUM-220690 Fitting, Hose End, Straight, -6 AN Hose to Female -6 AN, Aluminum, Red/Blue Anodized, Each 2 $9.76
SUM-230610 Hose, Braided Stainless Steel, -6 AN, 10 ft. Length, Each 1 $36.95
 

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Discussion Starter · #10 ·
I just read that I will need an upgraded fuel pump. Is this true?
 

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You should with a SC, it needs the higher boost pressure in the pump to overcome the blower pressure. It needs to be boost referenced, so it increases pressure with respect to the boost of the blower (or turbo).

The L67 injectors flow say 36 lbs/hr @ 3.5 bar, and you go into boost, say 10 psi for the sake of easy, then the injectors that are referenced at atmospheric pressure (0 psi), are now only flowing 26 lbs/hr, because there is now a positive pressure of 10 psi at the tips of the injectors. I think L36 injectors are 28 lb/hr, not enough for a boosted 3800.

So yes, you NEED to. Can you survive without? yes, but extremely dangerous to the life of the pistons....

I just read that I will need an upgraded fuel pump. Is this true?
 

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Discussion Starter · #12 ·
You should with a SC, it needs the higher boost pressure in the pump to overcome the blower pressure. It needs to be boost referenced, so it increases pressure with respect to the boost of the blower (or turbo).

The injectors flow say 36 lbs/hr @ 3.5 bar, and you go into boost, say 10 psi for the sake of easy, then the injectors that are referenced at atmospheric pressure (0 psi), are now only flowing 26 lbs/hr, because there is now a positive pressure of 10 psi at the tips of the injectors.

So yes, you NEED to. Can you survive without? yes, but extremely dangerous to the life of the pistons....
Pressure is determined by the regulator.
Injector flow is determined by the injectors.

I guess the question is whether or not the pump can provide a sufficient volume of fuel.
 

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yes your pump is fine, you will need the L67 injectors
 

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GM put a dual speed fuel pump on for a reason, and the PCM triggers it on/off as needed to keep up with demand (like when it approaches or just passes boost threshold). Yes, the reg must be boost referenced.

Pressure is determined by the regulator.
Injector flow is determined by the injectors.

I guess the question is whether or not the pump can provide a sufficient volume of fuel.
 

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Hey Tony, another Bonneville expert to chime in.

IF you decide to change the trans, then you will need PCM programming to make the trans shift properly, (easy).. and just for clarification, you would need a new PASSENGER side axle if you get a HD trans

speaking of that, your current harness will work, with some adaptations for the BBV,BCS and relocating the MAP sensor. This is simple, and there is also a harness adapter that one of the vendors sell to make everything easy. The Final thing is to get the PCM programmed with the L67 Bin File and Trans settings, so the car knows what i happening under the hood.

There have been alot of people that have swapped engines in the W bodies, most dont do it in the H body but its just as simple and easy.

any other questions ask awau
Is there any radiators from another car that will fit a 97 Bonneville SSE
 
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