Power boost for a 308gtsi

Are there any practical and not super expensive options? I don't want to put a blower on it. FWIW, We have no state emissions tests in Florida. At least not now.

Morrie

 

Hemi powered flatbed

You have a QV, so there's not a lot of options. Turbocharger, supercharger, or maybe carb conversion for a few horses. The money is better spent "upgrading" to a later model.

 

Here ya go!
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no

 

It's a 1980 2-valve car. I have never driven one, but will do so this weekend. I don't know how it compares to my previous 308 QV and 328.

 

Ah, sorry, your profile threw me off. Best answer, early cams and a carb conversion. Ask Russ (snj5) about that. Probably still not cost effective

 

In that case, throw a couple extra hampsters in the engine compartment.

 

A fellow who used to frequent the forum did a bit of work on the 2V injecteds. He claimed they would run okay with early carb cams, and IIRC, he ran intakes only and left the original exhausts. There were some other discussions about recalibrating the WUR or otherwise altering fuel pressures at idle to keep the fluttering sensor plate from altering fuel mixture at idle and low speed.

The CIS does not like reversion waves (backflowing air pulses) hitting the sensor plate, it causes the fuel mixture to go over rich. And the early cams being longer duration do produce reversion. But its been discussed that its not as bad as claimed and can be tuned down to make the car quite driveable.

One other person claimed that with ported heads and early carb cams on a CIS motor, to have pulled nearly 270HP RWHP on a dyno, but this was never confirmed.

If I had one of these cars I would try the early carb cams and see how it runs. You can always go back if it doesnt work out well, or keep going forward with carbs, etc., if it does. Another option is a larger throttle body and larger smooth bore intake snorkle (between the CIS unit and throttle), which should work in theory to add "some" power. But as no one ever opened up the plenum behind it to the same bore diameter, no change in HP was ever noted (nor is this surprising). Unfortunately, Kermit left the scene and disappeared a couple years ago, and no one has done any further work on these cars since.

 

+1 to everything Paul said.

The basics:
Exhaust: replace old heavy muffler/thermal reactor with lightweight true dual flow ehuast. See current cheap 308 exhaust thread to get started, but many more.
Make sure everything there is in the best condition and works well.
Your current K-jetronic will fed up to 270 hp, if you can get your engine to flow that much air (cams, heads). It is also a terrible flow restriction in itself, and you will pick-up 20 hp just retro-fitting to Webers.
If you want to keep the original injection, the order is: K&N air filter (debatable), metal flow tube replacing rubber accordian tube to throttle, cams with more lift, cams with more lift and a little more duration, port the heads, port the heads with larger valves. We've never talked about extrude honing the manifold and plenum, but a some Porsche guys do that.

Good luck!