3800 series engine

[jaguarking11]

Hello Folks.

I am thinking about building a lotus 7 replica car, aka locost. Weight is a must, so is horsepower.

SO....
I have a few questions regarding the 3800 series engines, specificaly the 3800 supercharged blocks.

Anyone have data on the weight differences between the SC and non SC models?

Is there a decent 5 or 6 speed manual (RWD) I can fit to a 3800sc out of a early to mid 90's buick or olds? I am looking to keeping cost down so an existing vehicles tranny is a must.

Now the important part. What can be achieved with these engines and how. Does decreasing the pulley on the stock supercharger make sense? I am looking at around 300-330hp with matching torque.


Most importantly I would like to keep the vehicle on a strict diet of roughly 1200-1500lb so would this be even be possible with a 3800 and manual transmission matched to a mazda independent rear axle? Don't worry about the mazda rear axle, its American made.

Any info from someone enthusiastic about these engines would greatly help.

 

[kshef]

300+ crank hp and 320+ ft lbs is easily within reach with bolt ons
i ran 13.8 @ 99 weighing 4060lbs

i've read (i'll see if i can dig it up) about someone using an F-Body flywheel on the old fiero getrag 5 speed manual

1500lbs will be tough to accomplish..i'd say the engine/trans is gonna be 500lbs

you might consider using an L36 N/A block and supercharge it...these blowers aren't very efficient so you're better off with the higher compression and not working the blower as hard

 

[jaguarking11]

300+ crank hp and 320+ ft lbs is easily within reach with bolt ons
i ran 13.8 @ 99 weighing 4060lbs

i've read (i'll see if i can dig it up) about someone using an F-Body flywheel on the old fiero getrag 5 speed manual

1500lbs will be tough to accomplish..i'd say the engine/trans is gonna be 500lbs

you might consider using an L36 N/A block and supercharge it...these blowers aren't very efficient so you're better off with the higher compression and not working the blower as hard

what can a stock l36 take? Whats the compression ratio?
I am not looking for monster hp as the car will esencialy be uncontrollable with too much hp. As for 500lb for an engine transmission combo, thats actually pretty dam good as the body will weigh about 400lb with the nosecone and panels. The rest of the weight will be axle and suspension + seats & gauges.

the fiero transmission is not something I would consider unless I wanted to go awd. The fiero transmission is esencialy a fwd config transaxle put in the rear. I am looking for something along the lines of a t5 transmission to get rwd config.

Thanks for input, Keep em coming guys.:smile:

 

[kshef]

it's 9.6:1...there are cars out there with over 500hp on stock bottom ends

if you end up at 1500lbs. a stock supercharged motor will get you down the road pretty well(probably low 13's)...combine that with headers, smaller pulley, intake, and tune, thats gonna be a quick little car

 

[jaguarking11]

it's 9.6:1...there are cars out there with over 500hp on stock bottom ends

if you end up at 1500lbs. a stock supercharged motor will get you down the road pretty well(probably low 13's)...combine that with headers, smaller pulley, intake, and tune, thats gonna be a quick little car

Its going to be a corner carver machine.

Thanks for the input. I found a website that sells a adapter plate to mount a 3800 to a 5speed s10 trans. Things are starting to come together.

I have a question though. How hard would it be to get a 3800 close to 300hp in N/A form? lets say I shave heads and increase compression ratio to say 10:1? How rev happy is this engine? How well is it balanced? Whats the highest RPM this thing can run happily at?

 

[steveX]

its eazier with this application.

forget the 4t65E-HD this monster will need the 06 pontiac G6 (F40) six speed transmission.

the sleeper

making 300+hp from a 3800 N/A motor will need lots of work, you will need a performance camshaft, ported heads will help, headers, DHP PCM, and others.you can also remove the balance-shaft. i have spin the 3800 s/c all the way to 6,200rpm with the balance shaft remove. increasing the compression ratio will not bring you much power, it will more bring you detenation. plus the increase in cc will not should much Hp gain. keep it at 9.5:1 factory setting. the 3800 engine is a very stronge unit. i have produce 425hp from a stock modified 3800 s/c. good luck keep in touch.

 

[cstavro]

as much as i love the 3800, it's 390 lb. a manual tranny = ~140 lb. stock valve springs are 70 #. 6200 rpm isn't bad! 105# springs will get you over 6500 rpm. a 206°-210° cam, 1-5/8" headers, and ported heads will get you near 300 n/a.

the ecotecs (even the 2.2) will make an easy 300 hp turboed. they weigh 285 lb. the solstice uses the canyon's 5 speed. it's ~120 lb. it's 'only' 100 lb less, but it's 5 lb/hp vs 4.67 lb/hp, and it's totally off the front end. it'll increase roll, and understeer.

why not try a 3500/3900? they have better aluminum heads, and weigh 370 lb. 210 hp n/a from the factory. forged crank, pm rods...they can take quite a lot of hp.

hth

 

[kshef]

increasing the compression ratio will not bring you much power, it will more bring you detenation.

yes it will give you power...you won't be working the blower as hard, reducing parasitic loss and outlet temps

 

[steveX]

yes it will give you power...you won't be working the blower as hard, reducing parasitic loss and outlet temps

NOway.. boring the cylinder just weaken the cylinder walls (trouble). i wounder what will happen when serious boost is apply to over-bore engine..BOOOM.

its never wise to over-bore a force induction motor. its alway better to step up to the next cubic-inch like a 4.1 or 4.3 if POSSIBLE .

Plus i was saying NOT TO OVERBORE THE N/A 3800 motor you will see NO or MINIMUM gain . if you do over-bore the 3800 s/c motor, i hope you don`t end up with a CRACK cylinder wall.

so if you saying over-bore will make power, then the downside is a damage cylinder.

 

[jaguarking11]

NOway.. boring the cylinder just weaken the cylinder walls (trouble). i wounder what will happen when serious boost is apply to over-bore engine..BOOOM.

its never wise to over-bore a force induction motor. its alway better to step up to the next cubic-inch like a 4.1 or 4.3 if POSSIBLE .

Plus i was saying NOT TO OVERBORE THE N/A 3800 motor you will see NO or MINIMUM gain . if you do over-bore the 3800 s/c motor, i hope you don`t end up with a CRACK cylinder wall.

so if you saying over-bore will make power, then the downside is a damage cylinder.

I was talking about increasing compression ratio, not increasing cylinder size.

I am not considering boring or stroking the block. I am looking at the colorado 3.5L unit witch can easily be bolted to the 5speed manual.

 

[Brad Zeidler]

Just get a tranny from a 96-02 3800 L36 powered Camaro or Firebird. It's not classified as a T5 because it no longer has a mechanical speedo hookup, but that's what it is. You won't need any adapter plates. Just take everything, the flywheel and all will bolt right up no fabbing. I have a good flywheel that needs resurfacing because I had already bought a new one when I started my reardrive conversion on my 87 Shelby Charger. Someone on the Camaro Firebirdv6.com site has a 3.8 tranny for sale right now

 

[Brad Zeidler]

Here's the link 3.8 5 speed trans - FirebirdV6.com/CamaroV6.com Message Board

 

[jaguarking11]

I didnt know these things would be a direct bolt on. Thats awesome. The transmission prices seem to be cheep too.

things are starting to look good.

 

[Brad Zeidler]

Let me know if you need the flywheel

 

[cstavro]

as far as weight goes...gm killed the sc 3800 and used the LS4 with 303 hp. the v8 is lighter!

the dohc aluminum v6 weigh just as much as the 3500/3900 - 370 lb. abbott racing heads has a n/a 3800 with 271 whp.

GM3800V6

the 3800 heads can't touch the 3900, and you also get variable intake, and variable cam phasing. i can see availability problems for the 3900.

edit: you *could* use a camaro tranny...but that means you'll have the engine up front?? in such a light car, that'll really throw the balance off. you want ~55% of the weight on the rear tires. mid engine is your *only* choice. you can have it transverse, like the fiero...or longitudinal with a porsche 914 tranny. if you want a front engined car, turbo/sc an ecotec.

 

[steveX]

Intake Stock
Stage 3

Lift
.100" 55.0 62.0
.200" 114.3 128.0
.300" 155.7 185.9
.400" 177.5 213.0
.500" 184.7 225.8
.550" 186.3 230.0
.600" 188.9 232.5

Exhaust Stock
Stage 3


.100" 45.3 52.0
.200" 98.2 107.6
.300" 132.1 154.9
.400" 145.5 166.9
.500" 148.1 173.4
.550" 151.6 176.6
.600" 152.6 178.2


I have got way better flow number than listed above.

its hard to beat the D-port design.

 

[jaguarking11]

The car will actually be front heavy but not by much the drivers seat is inches from the rear axle. The balance will be very good.

 

[cstavro]

I have got way better flow number than listed above.

steve - who's flow numbers are those?? and do you want to quantify 'way better'?

i have better numbers than those...then my head porter unshrouded the valves...and lost intake flow once i get it fixed, i expect ~240 @ .550".

jaguar...230 cfm will support 345 bhp naturally aspirated...with big cam, compression, headers. even a bone stock engine will support 500 hp with a proper turbo.

people feel funny the farther they are from the center of gravity. you'll feel more yaw, and more bumps.

it sounds like an interesting project. how far advanced are you? do you have any pics?

 

[jaguarking11]

At this moment I am researching the drive train of the vehicle. The next step is either going to be purchasing a new chassis or make one.

As of now nothing real to show off. I will post a project log when I feel the time is rite. :wink: Don't expect anything until mid summer. The 3800 is not the only engine I am looking into either. I am looking at the new vortec 4200 as well. However mounting that thing slanted will require a major reworking. However the power figures are very impressive. The third engine I am looking into is the thuderbird supercupe 3.8L supercharged block. They are known to do about 300rwhp with just a pulley upgrade. the weight is my biggest concern. every lb matters.

 

[cstavro]

since every pound matters, the ls2 weighs less than the 4200! 420 lb fyi.

the ecotecs are around 255 lb, and the turbo ecotec is a little heavier at 286 lb. you can easily get 300 hp out of a 2.2 with a t28 turbo. the 2.4 makes 177 bhp - and close to 200 with cai and headers.

what are you doing with this car? why does it need 300 hp? remember, the lotus exige has 220 bhp (and only 167 lb-ft), weighs 2077 lb, and it does 0-60 in 4.1 seconds.