throttle body upgrade/swap?

[kilo_tech17]

i was wondering if i would be able to swap my throttle body for a slightly larger one that would fit or would be able to fab fit? i have a 79 900 turbo. if i could get one that is larger that would fit and work would it effect the fuel injection system on the car? or would it not be worth it all the while. i plan to auto-x it this coming jan-march when the next season starts. i'm trying to think of future upgrades that i will be able to do on the car. thanks

[Squaab99t]

Welcome. Looks like you have a B motor in your 79. Every so often on Ebay a Weber TB will show up. $s. Said to be a larger dia. I have never seen one to measure. I'm pertty sure 16v TB will fit, not positive. Not sure what class you will be auto X, check the rule book on what you can change for what class. I would look for the 6 port fuel dist (2 are blanked off). adjust the boost, disable the fuel pump over boost, but remember the B head is getting very hard to find. so not too much boost Cleaning the injectors, KN drop in filter, general tune up stuff. There is a bunch to do you just need to know how to tailor it to fit the class.

[sonett1]

i am sure Group 9 or similar over there in the US used to offer throttle bodies with a larger diameter/throttle plate on an exchange basis?

[ejenner]

IMO with forced induction you needn't bother enlarging anything unless your looking for serious power.

Should have a nice low compression ratio on that early motor so just up the boost, keep an eye on the knock situation and consider water injection.

Handling, suspension, brakes and tyres are probably more important.

[sonett1]

Regardless of whether your engine is N/A ot turbo, the big gains are when you get more air into the engine.

[ejenner]

No doubt. but when you got a big air pump pressurising the inlet manifold you're off to a flying start. A larger throttle body is quite insignificant and so is a lot of the inlet tract. Just bump up the pressure so when the valves open air is crammed into the combustion chamber. Turbocharging is a shortcut to high performance and stock system can be tweaked. It's true that bigger spaces everywhere will allow more air through the head but higher pressure can compensate for a lack of space.

[sonett1]

All things being equal, either N/A or turbo, there still comes the point when the engine can only flow so much air, have a look at this to get an idea what i am getting at............... http://www.pumaracing.co.uk/turbo.htmMy approach to performance tuning is that with 4 stroke engines, the starting point should be with the cylinder head, without getting the head done first any other modifications relating to the engine will not be at their full potential.

[ejenner]

totally agree. But an extra 50bhp above stock is no trouble at all on a forced induction system. It is important for hopeful tuners to know that it does get to a point when extra pressure in the manifold isn't producing more power. Couldn't say what that figure is but when you hear all that talk of "wow - look how high my pressue gauge reads now" that is probably the time when those extra psi's aren't doing anything.

Riding down the straight at Bruntingthorpe in the Noble M12 watching the boost gauge proved to me that pressure is pretty un-important. When I pointed out that the Noble requires something like stock T16 pressure to produce all it's power Matt Faulks said "high pressure is a sign of a restriction" which I thought was spot-on.

[kilo_tech17]

i have been to a couple of events and have talked to some of the managers of the chuckanut sports car club and they said i would be able to race it in the novice class, being able to upgrade suspension, shocks, intake filter, sway bars, etc but all to stock design. i already have a k&n drop filter in, i have intrax springs with newer kyb's that came on the car. one thing that i am slightly worried about is i have a 2.25 exhaust on it that isnt stock. i just hope that doesnt put me in a higher class. the water pump shaft also has broken on it that i was goin to replace with an electric pump. untill recently i found a full kit with the new shaft+impeller+seals and all. i am unsure of how far into the classes i will go with this car but i am goin to start off with it and go up utill it is more practical to change cars. i have read a bit on the puma racing site and that is a big help, thanks for that link sonett1. i will try and get pics of progress on the car and i will keep you guys informed on how i do with auto-x, thanks again

[ejenner]

In its day the 99 was able to win races so should be competitive for a while.

VinceT from this site competes with a 99' so you might do well to check out his website and maybe ask him some questions: http://members.shaw.ca/saaboteur

Also James from Team SaabWorks who races 99's and 900's knows a lot about competitive Saabs. His username is rally900 and his website is: http://www.saabworks.com

[kilo_tech17]

as far as installing a 900t intercooler, that i have with original hoses and piping, is the mechanical fuel injection able to compinsate for the cooler charge? i also saw an "upgrade" kit for the stock intercooler, the one that fits behind the driver headlight, that had new samco hoses and larger diameter piping like 2.25 or 2.5. would that also be a decient upgrade? i just dont know how it will all act with the fuel system.

[Saab-Daniel]

No problem, an intercooler will work fine on a t8 like yours (and mine). A 9000 intercooler is a even better solution, stick it in front of the radiator, and will give you quite a nice power-upgrade.

Daniel.

[ejenner]

Maybe an original 900 IC stuck in front is better than a 9k IC?

[Saab-Daniel]

It might be, but piping is more difficult...

Daniel.

[Eric van Spelde]

Two 900 IC's side-to-side with custom top and bottom end tanks should be good - in all cases, be prepared to do some metal cutting. Personally I'd sooner go for a liquid/air IC system, but that's just my liking for short, simple intake tracts and dislike for structural changes...

[Si]

Two 900 IC's side-to-side with custom top and bottom end tanks should be good - in all cases, be prepared to do some metal cutting

No metal cutting nessesary, just remount the radiator