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Power enhancement ideas


jonlabree

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1 hour ago, Ronnie said:

Looking at this photo again. How hot does the intake pipe get? I was just wondering if there is a lot of heat transfer between the exhaust side of the turbo and the intake air side. Do you have a photo of the pipes with heat shields in place?

 

 

DSC00923.thumb.JPG.58e8f97f110f8f0b03d0f

There is no doubt there is some heat transfer, but not as much as you would think when a couple hundred cfm are flowing, but for cruising, yes it is a concern. I mount my intake air temperature sensor directly into the throttle body so the ECM sees actual air temp. to accurately control the timing. In this particular setup, I never completed the direct hot air feed. I already had a front mounted intercooler installed  so I opted to use that for the air inlet. The compressor outlet is rotated to point straight down where it runs down and forward to the intercooler and then back up where the charcoal canister would be and then to the throttle. I discovered the boost was so tame, that the intercooler is not needed and a future iteration will be routed as shown above. Bear in mind, I generally have my hot parts ceramic coated so radiation is less but I do make tin heat shields where appropriate.

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1 hour ago, 63viking said:

Is there a reason you can't mount the turbo in the crossover pipe and continue the down pipe from there?

No, there is no reason it can't as long as the turbo can be located and oriented so everything else will work. Even a small assembly like this takes up more room than you would think and there are other things that get in the way, like the transaxle TV cable which sticks straight up. I have considered relocating the battery to the trunk, locating the turbo in its place and feed it from half or all of the engine. In that location, it looks like a nice cold air inlet could be made similar to what's on the driver's side and run the compressor outlet either across the front of the engine to the throttle or run out through the front to an intercooler and they back out through the existing hole where the stock inlet is now and on to the throttle. I'm sure I haven't exhausted all possibilities and while not necessary for the half turbo, I relocated the vacuum bomb and the cruise control servo to the crossbar for the strut towers.

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1 hour ago, 89RedDarkGrey said:

(that's why Builders "in the know" are mounting stuff in the back, away from the hot engine)

In a perfect world, the optimum place would be directly to the existing rear manifold outlet if you can find the real estate, get cool air to the compressor inlet and from the outlet back to the throttle. The darn sidewinder engine makes a lot of that difficult unless designed in from the start. The real rear mount systems have different but similar issues to work around. A good place for a rear mount; I would ditch the stock fuel tank so the turbo could be tucked up a bit to between the rear hatches which would shorten both the exhaust and pipe to the throttle. Of course it would need a tank under the rear, sort of trade the locations as normally done. 

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Or like the later 3800 Supercharged V6 ..........save your grey matter and use what GM engineered.

I toured the Hennessy performance shop down in Kyle TX last fall and they were taking that high performance Dodge and modifying it.........mostly with software, they changed the blower pulley for more boost, new exhaust and the rest was

modifications to the ECM chip..........how much could you get out of the Reatta by modifying the timing, injectors and transmission shift points?

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20 minutes ago, Barney Eaton said:

how much could you get out of the Reatta by modifying the timing, injectors and transmission shift points?

 

You can very easily upgrade an LN3 and an L27 to tear up their transmissions. The L67 was Factory coupled with an SC, but only after some major tweaking. The automatic transmission has always been the weakest link. Higher pressure pump, adjustable regulator, a remapped ECM PROM, and larger injectors could easily snap the internals of a plain OEM TH440/4T60 ME9 on an '88-'89 Reatta. 

 

The Series I Supercharged engine went through many internal changes and the horsepower changed rapidly between the time it was introduced and the time that the Series II L36 was introduced. The M62 supercharger was manufactured by Eaton, exclusively for the GM 3800 engine. HP was rated at 205 for 1991-1993 engines (models vary), and 225 for 1994-1995 engines. Some of the additional horsepower for 1994-95 engines was gained by using epoxy (not Teflon as commonly believed) coated supercharger rotors to improve efficiency, and a larger supercharger inlet and throttle body. The 1994-1995 utilized a 2.85-inch (72.4 mm) pulley versus the 2.55-inch (64.8 mm) pulley used on the 91-93 supercharger.
 
Applications:
1991–1995:
Buick Park Avenue Ultra
1992–1995:
Oldsmobile Eighty-Eight LS (opt), LSS (opt)
Oldsmobile Ninety-Eight Regency Elite (opt), Touring Sedan
Pontiac Bonneville SE with H4U RPO, not badged - SLE (opt. SC package), SSE (opt) & SSEi
1995 Only:
Buick Riviera(Opt)
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1 hour ago, Barney Eaton said:

Or like the later 3800 Supercharged V6 ..........save your grey matter and use what GM engineered.

I toured the Hennessy performance shop down in Kyle TX last fall and they were taking that high performance Dodge and modifying it.........mostly with software, they changed the blower pulley for more boost, new exhaust and the rest was

modifications to the ECM chip..........how much could you get out of the Reatta by modifying the timing, injectors and transmission shift points?

I haven't found much improvement with chips, fuel pumps or injectors. Those are usually supporting modifications for actual physical changes to the engine such as a camshaft changes, forced induction, running a different fuel etc... The engine just doesn't breath deeply enough, so forced induction works well. I agree if you want plug and play large power increases, the factory s/c option makes a lot of sense. One place where chips, injectors and fuel  pumps would be a necessity would be to run E85. If you can't get enough air in, use a fuel that carries some of its own oxygen, for a net tq. gain. Of course you use 30ish% more, and would be even more effective it the compression was bumped up at least two whole numbers, or more.

 

I don't know enough about the transaxle to comment much about the shift points. I know the TV cable has some effect on it but I think the governor in the trans. would need to be modified to change the shift point. This is for the mechanical trans. in 88-90. Probably wouldn't help a lot if the engine has fallen on its face 1500 rpm back :rolleyes:

Edited by 2seater (see edit history)
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2 hours ago, 2seater said:

I don't know enough about the transaxle to comment much about the shift points. I know the TV cable has some effect on it but I think the governor in the trans. would need to be modified to change the shift point. This is for the mechanical trans. in 88-90. Probably wouldn't help a lot if the engine has fallen on its face 1500 rpm back :rolleyes:

 

Yeah that is one drawback about this tranny, whereas I have heard of people making adjustments to the shiftpoints on other models to get better performance. Actually if you do not have the TV cable adjusted properly on our setup the OD doesn't function right if at all, I know from experience.<_<

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Putting a switch on your car to turn off the torque converter lockup makes the car feel like is has better performance. With the switch turned off the car accelerates better (in my opinion) because you don't have to wait for the converter to unlock when you mash on the gas pedal . It allows the RPM to jump up immediately allowing the engine to accelerate better. Otherwise you have to keep mashing down on the gas, (usually lugging the engine), until the converter unlocks. I personally think having the converter unlocked is easier on the transmission because it eliminates the abrupt transition between lock and unlock of the converter. When I drive on the interstate, which is seldom, I flip the switch to the on position to lower the RPM and to get better fuel mileage. This idea probably isn't for everyone but I thought I would throw it out there since were talking about performance.

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10 hours ago, 89RedDarkGrey said:

Here's some nifty info for us- 

 

 

Interesting but I noticed they didn't really specify that the next generation, the immediate predecessor to the 3800, was not used in the GN? The GN has the traditional flat tappet lifters, rocker shafts and an oil pump driven from a camshaft drive. It didn't have a distributor but used an external cam position sensor in the same location as the distributor which drives the oil pump in the old traditional way. Not a big deal I guess, just unclear.

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While I'm on the subject of things that makes it feel like you are getting better performance, I wonder if my cold air intake actually makes any more power. It does give the sensation of having more power because it gives the engine a little more (louder) sound when you open up the throttle pretty wide. The stock air cleaner is almost silent. The cold air intake combined with the unlocked torque converter really gives a seat of the pants feeling that you are accelerating better. I really doubt I've done much to improve performance but it makes my car more fun to drive. :)

 

Air Cleaner (14).JPG

 

Air Cleaner (15).JPG

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29 minutes ago, Ronnie said:

Putting a switch on your car to turn off the torque converter lockup makes the car feel like is has better performance. With the switch turned off the car accelerates better (in my opinion) because you don't have to wait for the converter to unlock when you mash on the gas pedal . It allows the RPM to jump up immediately allowing the engine to accelerate better. Otherwise you have to keep mashing down on the gas, (usually lugging the engine), until the converter unlocks. I personally think having the converter unlocked is easier on the transmission because it eliminates the abrupt transition between lock and unlock of the converter. When I drive on the interstate, which is seldom, I flip the switch to the on position to lower the RPM and to get better fuel mileage. This idea probably isn't for everyone but I thought I would throw it out there since were talking about performance.

I agree, it does let the engine operate more responsively probably at a small cost in mileage. I did something along those lines when I started trying my own chip burning. I raised the minimum lockup speed to something like 55mph. Not a perfect solution but for urban/suburban driving it does feel a bit peppier.

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2 minutes ago, Ronnie said:

cold air intake

 

As usual- all those do is sound cool. Without a cover- to properly duct in actual outside ("cold") air- those setups generally suck in hot (warmer than outside engine compartment) air, slightly skewing any reading put out by the Air Charge Sensor (assuming most users even hook them up) and ultimately changing the air/fuel map. It's ok if you're retuning anyway, or have a completely Aftermarket ECM-ECU-PCM or a variance of those, in a more "modern" setup.

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Does anyone have thoughts to share on the supercharged conversion? Even better if you had the car with both engines. I am truly curious on the results and experience. 63Viking mentioned possibly adding a turbocharger as well, which would really be new ground, and got me to thinking about doing a s/c engine myself. I dropped off the rusty block I received from Daves89 at the machine shop to have it checked out for possible use. If it can be saved I am warming up to the idea of adding a supercharger to see what that experience is like.

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7 minutes ago, 89RedDarkGrey said:

 

As usual- all those do is sound cool. Without a cover- to properly duct in actual outside ("cold") air- those setups generally suck in hot (warmer than outside engine compartment) air, slightly skewing any reading put out by the Air Charge Sensor (assuming most users even hook them up) and ultimately changing the air/fuel map. It's ok if you're retuning anyway, or have a completely Aftermarket ECM-ECU-PCM or a variance of those, in a more "modern" setup.

Yes, there is a chart the ECM reads to adjust timing based on inlet air temperature. LV8 is an engine load calculation based on several inputs, with 256 being maximum load.  It has pretty large cells so its not really linear but this is what it looks like:

 

MAT chart.jpg

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2 minutes ago, 2seater said:

Yes, there is a chart the ECM reads to adjust timing based on inlet air temperature. LV8 is an engine load calculation based on several inputs, with 256 being maximum load.

 

I'm a little confused. Are you saying I may have hurt performance with the chrome plumbing I added? :)

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15 minutes ago, 2seater said:

Does anyone have thoughts to share on the supercharged conversion?

 

I have actually thought about doing just a supercharger bolted on my engine and changing the pulley size to give a very mild boost that would be easy on the transmission. I never got really serious about it but I did check into it a little a few years ago. If I remember correctly it might be possible to do without swapping the whole engine.

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4 minutes ago, Ronnie said:

 

I'm a little confused. Are you saying I may have hurt performance with the chrome plumbing I added? :)

Sorry, that wasn't my intention, I was just adding detail to the previous post. I believe you relocated your temperature sensor to the new inlet pipe, so the ECM should be getting correct information. Easy to see what the incoming air temperature is in diagnostics so you can judge if it may be an issue. The other thing that many cone filters do for you is give a larger filter area than the stock panel filter.

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4 minutes ago, 2seater said:

Easy to see what the incoming air temperature is in diagnostics so you can judge if it may be an issue.

Should I be comparing that reading to outside ambient air temperature to know? I wish I had done some testing like that before installing the cone filter. Actually the extra intake noise was what I was going for. I didn't really expect any performance gain.

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9 minutes ago, Ronnie said:

 

I have actually thought about doing just a supercharger bolted on my engine and changing the pulley size to give a very mild boost that would be easy on the transmission. I never got really serious about it but I did check into it a little a few years ago. If I remember correctly it might be possible to do without swapping the whole engine.

That would be my intention as well. Remember F14Crazy? He had a long thread about doing exactly that. There are subtle differences internally on the s/c engines, which I think became more robust as different variations increased in power. The early 90's engines are little different with possible things like full floating piston pins which would show up as different part numbers but otherwise similar. Same heads, block, cam as the n/a version.

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My '71 Nova had a "Thermostatic" air cleaner on it's 250 cid  1 bbl Rochester. Just below the snorkel, was a duct attached to a sheet metal shroud around the exhaust manifold called the Heat Stove. A bimetal sensor in the air cleaner- controlled whether vacuum was operating a diaphragm servo- that controlled a damper door to the Stove. The valve got stuck once- and the heated air made the hot engine ping. Warm air in a cold, carbureted engine will make it run smoother.

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10 minutes ago, Ronnie said:

Should I be comparing that reading to outside ambient air temperature to know? I wish I had done some testing like that before installing the cone filter. Actually the extra intake noise was what I was going for. I didn't really expect any performance gain.

Sure. The closer it is to the outside air temp. the better. I usually see several degrees warmer when in traffic or very low speed just from the general warming of the immediate area around the car but cools once moving. From the chart, there is little chance it is pulling timing until you get over 33*C or 91*F

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3 minutes ago, 2seater said:

Sure. The closer it is to the outside air temp. the better. I usually see several degrees warmer when in traffic or very low speed just from the general warming of the immediate area around the car but cools once moving. From the chart, there is little chance it is pulling timing until you get over 33*C or 91*F

I'll try to remember to check it out when warm weather rolls around.

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22 minutes ago, 2seater said:

The other thing that many cone filters do for you is give a larger filter area than the stock panel filter.

 

And anyone who reads this- please- don't ever use one of those filters you spray "wax" or some "coating" on. It gets on the MAF and cooks to it, and could easily ruin the MAF. 

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4 minutes ago, 89RedDarkGrey said:

I'd be weary of big power on a 2 bolt main setup.

Yes, discretion is needed. I think the trans. will scatter long before the engine will as long as it is tuned well and doesn't knock itself to death. From much information I have found over the years, is our 3800 is capable of about 500 flywheel hp before you drive over the crank. If I could get somewhere close to half of that, I figure it would be just right.

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Gentleman:  I have played with my LN3 3800 for 7 years and in that time I have tried several  changes to increase horsepower.

But I have settled on the  last one as the best.

1-- I bored out the block 30 over.

2 --installed 95 pistons.( 9.8 to 1 compression)

3-- installed a custom ground Crane cam.

4-- Heavy duty valve springs and retainers.

5-- Ported & polished, intake runners, supercharger, Heads. exhaust manifolds, and Throttle body.

6-- Removed the canister and run the intake down thru the hole in the fender well, with NO 90% turns.

      (This allows fresh cool air the enter the engine)

7-- installed water/ menthol  injection to cool the supercharger.

8-- Installed a NOS system with a 50 hp pill.

9-- Ceramic coated the, Intake manifold, throttle body, Supercharger, and exhaust manifolds.Installed a (all inside and out) 

      including the impellers.

10-- The Supercharger has a  2.5" pulley. (smallest one you can use)

11-- Excell coils and  E3 plugs.

12-- electric switch on the Supercharger that shuts off the vacuum to the bypass.

          (Allows more boast)

13-- Installed a oil filter mount and external cooler. ( allows use of the larger filter)

14-- Adjustable, advanceable fuel pressure regulator.

15-- 36# injectors.

 

As for the switch on the lockout, I have used that foe the past two years.

 

 

 

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