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Discussion Starter #1
I've been looking for a 900 SE turbo for cheap for a while now, and I keep coming across cheap 900 S. I mentioned it to my friend who comes from the V8 world and he suggested I just supercharge the n/a 2.3. I don't see why this isn't possible, I'm a machinist so I could easily create a bracket to mount a centrifugal supercharger and the correct sized pullies to run an appropriate amount of boost.

This will not be my daily driver - I want to make over 300 whp on race gas with it. Would I have to use lower compression pistons with it? Do B235 internals (viggen, 9-5) work with the B234? Would I be able to tune the stock ecu (manual) to support the supercharger?

Thanks
 

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Why don't you just turn the na into a turbo? It will take a lot of work to convert the engine over to handle any kind of boost, why not stick with what saabs run well with?

You can get a turbo saab to run well over 300hp on pump gas if you put the right stuff in it.

Also, a turbo is a different system than a turbo, I'm not sure if the ECU will be able to run with a supercharger.

Just some things to check into. ;)
 

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Discussion Starter #4
I wanted to look into superchargers because every saab is turbo'd - no one is expecting to hear a supercharger whine.
 

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ELJonesy said:
I wanted to look into superchargers because every saab is turbo'd - no one is expecting to hear a supercharger whine.
That is a good reason, I can't knock individuality. Just check into some of the things I listed above and if everything is cool, then go for it.
 

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Discussion Starter #6
I was looking into getting this with the 2.0T, I think that it would elimate any programming problems I would have with supercharging the 2.3. With retarded timing and high octane gas the compression ratio might not even be too big of a problem....

What is the actual compression ration of the B234? I did a brief search but couldn't find an actual number.
 

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ELJonesy said:
I was looking into getting this with the 2.0T, I think that it would elimate any programming problems I would have with supercharging the 2.3. With retarded timing and high octane gas the compression ratio might not even be too big of a problem....

What is the actual compression ration of the B234? I did a brief search but couldn't find an actual number.
I honestly couldn't tell you whether or not that management system would work in a saab, you should get ahold of Nick Taliaferro at genuine saab, he's pretty good with giving knowledgable advice even if you aren't buying something from hom at the time.
 

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i've basically been here and done this, except we twin charged (as we referred to it) a 92 dsm

by that i mean we supercharged and turbocharged a 4g63, i wouldn't suggest doing this, ray ended up making almost 500awhp, but the top end was dead, we ended up making more power with just a big turbo

but basically if you want to do this i would suggest getting a supercharger from the gm 3800, cheap lol

starting with the 2.0 you will need bigger injectors, you can modify the stock intake manifold to accept the supercharger, your gonna propably want to change the headgasket at this point too. After that you need to measure out the serpitine for a new belt. all this is definatly within your range of experience

now to the point where it gets outta of anything you know lol, your gonna have to change the ecu, the cost for having someone custom tune your t5 is gonna be outragoues, i suggest getting a megasquirt, after that you need alot alot of time tuning that ecu, its hard to do because the supercharger is in boost at such a low rpm that you have run alot of fuel and taper it off towards the end

long math story short i ended up having to create a power series FOR EVERY 50 rpm through idle to to redline, than using maple i was able to simplify the equation in to a rough intergration for instantaneous fuel delivery throughout the power band, THANK GOD FOR MAPLE btw lol

really long story strait ater 6months and a motor later we finally got it running right, made 486 awhp w/o methanol injection working, the thing about it was anything off idle we made 20psi, than the turbo contributed another 18psi, but after working through parisitic losss we found that 50-70hp was lost near redline

anyways theres alot of this your not gonna run into, but some that you will fact of the matter is that you can't just slap a s/c on a car and expect it to run right, the amount of R and D that goes into every supercharger application is more than WE put into this one app.

i have been wanting to supercharger an 8v lately, as the k-jet system can be somewhat easily modified for high amounts of boost plus its got a nice little startup injector that you can tickle at low rpms to flow the fuel ya need lol

anyways if you decide to do it good luck!
 

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Discussion Starter #9
yeah you're right programming it is beyond my abilities but I should be able to do everything else.

I was considering using a centrifugal charger rather than roots....would I be able to fit the charger off of gm's 3.8 under the hood of a 900? Would be easier if the intake manifold was in the front, lol.

Thanks for all the help.
 

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ELJonesy said:
yeah you're right programming it is beyond my abilities but I should be able to do everything else.

I was considering using a centrifugal charger rather than roots....would I be able to fit the charger off of gm's 3.8 under the hood of a 900? Would be easier if the intake manifold was in the front, lol.

Thanks for all the help.
you know it might be tight, but i think it would fit
 

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You can find turbo NG900s for well under $3,000....which is likely what you'd eventually spend on rigging a blower system. :cheesy:

Superchargers on small displacement engines are barely worth the trouble, as mfyoung's experience shows...

You'd likely do better just adding a bottle to it.....;)

But anything's worth trying (which is easy for me to say when someone else'[s money and time are involved....:D )
 

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mike saunders said:
You can find turbo NG900s for well under $3,000....which is likely what you'd eventually spend on rigging a blower system. :cheesy:

Superchargers on small displacement engines are barely worth the trouble, as mfyoung's experience shows...

You'd likely do better just adding a bottle to it.....;)

But anything's worth trying (which is easy for me to say when someone else'[s money and time are involved....:D )
yeah its mainly true lol , you can just call me mike btw lol, the fact of the matter is the motor makes power so high in the rpm range, that the superchargers VE starts to hurt power, still gonna make more than stock, but in general s/c are no where close to being as effeicent as a turbo

lol a funny story from that install was when we had the car running pretty decent, and ray decides that he wants to show off and powerslide through a turn, well theres only an 1/8 tank of gas in it, and he starves the motor, and burnt the insulators on the spark plugs....compression kinda went to hell after that
 

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Discussion Starter #13
mike saunders said:
You can find turbo NG900s for well under $3,000....which is likely what you'd eventually spend on rigging a blower system. :cheesy:

Superchargers on small displacement engines are barely worth the trouble, as mfyoung's experience shows...

You'd likely do better just adding a bottle to it.....;)

But anything's worth trying (which is easy for me to say when someone else'[s money and time are involved....:D )
sure I can find 900SE's for under $3k, but the S I'm considering buying is $1200 lol.

Can you show me any proof of superchargers not being as efficient as a turbo on small displacement cars? Most other people have told me a supercharger would be more efficient than a turbo because a small 4 banger doesn't have as much exhaust pressure as a larger motor, but can spin a pully just as fast. I realize that I'll have a good bit of parasitic loss on the top end.

I'm open to any ideas or comments. From my point of view an s/c build on a saab is so much more interesting to me than the regular old bigger turbo, downpipe, intercooler build. That is the main reason I want to do this.

Again, thanks for all the advice guys.

edit: I asked before but I didn't get an answer...what is the compression ratio on the n/a 2.3?
 

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ELJonesy said:
sure I can find 900SE's for under $3k, but the S I'm considering buying is $1200 lol.

Can you show me any proof of superchargers not being as efficient as a turbo on small displacement cars? Most other people have told me a supercharger would be more efficient than a turbo because a small 4 banger doesn't have as much exhaust pressure as a larger motor, but can spin a pully just as fast. I realize that I'll have a good bit of parasitic loss on the top end.

I'm open to any ideas or comments. From my point of view an s/c build on a saab is so much more interesting to me than the regular old bigger turbo, downpipe, intercooler build. That is the main reason I want to do this.

Again, thanks for all the advice guys.

edit: I asked before but I didn't get an answer...what is the compression ratio on the n/a 2.3?

well do you want me to go threw the math? VE (volumetric effeicny) on superchargers, as well as the fact that at high rpms a motor more easily makes exhaust gases than it does spinning a pull, which means at high rpms s/c cause rather large peristic loses

not saying it wouldn't be awesome and like i said i've been wanting to do it on a pre 85 900c 8v motor for a long long time

mainly because k-jet is mech fuel injection, and with some tuning you can make it doe basically anything u want (well not anything) but its nice because you can taper fuel off towards the top end as you need less

you can also write a little program to tickle the startup injector if you need it
 

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Discussion Starter #16
Cliche` said:
The B234I's compression ratio is 10.1:1.
thanks! where are you from in CT? I'm in the danbury area.

mfyoung said:
well do you want me to go threw the math? VE (volumetric effeicny) on superchargers, as well as the fact that at high rpms a motor more easily makes exhaust gases than it does spinning a pull, which means at high rpms s/c cause rather large peristic loses

not saying it wouldn't be awesome and like i said i've been wanting to do it on a pre 85 900c 8v motor for a long long time

mainly because k-jet is mech fuel injection, and with some tuning you can make it doe basically anything u want (well not anything) but its nice because you can taper fuel off towards the top end as you need less

you can also write a little program to tickle the startup injector if you need it
You really seem to know what you're talking about heh.

Theres so much learn with this project, I'm excited to do it.
 

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ELJonesy said:
thanks! where are you from in CT? I'm in the danbury area.



You really seem to know what you're talking about heh.

Theres so much learn with this project, I'm excited to do it.
well this can be done for alot cheaper than everyone here thinks it can lol, but its alot of labor, and theres alot of roadblocks

the best advice i can give you is to get the gm 3800 s/c, and to get really familar with megasquirt

megasquirt ecus cost a couple hundred, from there just imput stock specs for the car (cam profile, timing , firing order) things like that, and get a palm pilot (there good for data loggers lol)

theres alot of technology here

although you know what i wound find intensely funny, is if you carbed the car

that would be cool lol
 

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i've been having the same issue of only seeing 900s models. as it happens, saabeh and i were talking about them last night, and he said that it would be possible to put a turbo with intercooler and all onto the 2.3 n/a engine and run maybe 5psi with an mbc. i figure, the lpt concept would be very safe without having to put in turbo pistons, and the intercooler would actually make it better than a typical saab lpt. it's not a supercharger, but it's an easy and relatively safe alternative.
 

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saabchilten said:
i've been having the same issue of only seeing 900s models. as it happens, saabeh and i were talking about them last night, and he said that it would be possible to put a turbo with intercooler and all onto the 2.3 n/a engine and run maybe 5psi with an mbc. i figure, the lpt concept would be very safe without having to put in turbo pistons, and the intercooler would actually make it better than a typical saab lpt. it's not a supercharger, but it's an easy and relatively safe alternative.
i think methanol injection in addition to the intercooler, and you would be safe running the turbo off the wastegate spring
 

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keep in mind, this wouldn't be the first thing i'd do to an n/a engine. i'd much rather do better flowing intake and exhaust to start. that alone will increase (or give great potential) to increase power.

patiently waiting though cuz it's impossible to find a good saab where i live.
 
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