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hotrodding the 4.3 V6 (tips & tricks)

198342 Views 190 Replies 52 Participants Last post by  sixsix
G'day, mates!

For those of you who have the venerable 4.3 v6, but want more power as well as throttle response this post is for you.

First off, I know how frustrating it is to have to work with all of the limitations built into the Astro engine: the small choked up t.b.i., or the weirdo c.p.i. "spider" intake manifold, mild cams, and weak ignitions, etc. :crying: There isn't one day that goes by that I don't think about how can I make my engine PERFORM better.

I will admit, a v-8 option SHOULD have been offered. As well as a turbo (look at the syclone/typhoon), or at LEAST take the tuned port intake (instead of cpi) and chop two ports off of it and tune it! (Would make an awesome project). But, since I rent an apartment, most projects HAVE to be done within a day or two.

So, most of these tips are Very doable with minimal downtime. 馃崒 Also, throwing big money at hipo parts doesn't always pay off. (Not in this day and age, anyways) Only the parts that are reasonably priced will be mentioned.......

1. Ram-air: bringing in COOLER air makes it easier for the engine to make power. (Try driving your van without a/c with the windows up on a 90 degree day, your engine is in the same scenario ) This can be made at home with dryer ducting with an aluminum sheets and some clamps. Cheap Cheap! :dance:

2. K&N filter: (8-10 horsepower). If you are in a dusty area, add a foam filter as a buffer. Paper filters restrict your airflow and most people forget about them and they get progressively dirty.

3. Morosso or Proform Air cleaner base: smooths out the airflow and allows removal of the stock "restricter" ring underneath it. This thing is TERRIBLE for performance.


0000tbi choker.jpg

















4. Raise the TBI injector pod: this allows more air to get in past the injectors. Turbo city has some goodies. View attachment 4 This spacer/gasket raises the injector pod 1/4". I raised mine to 1". :layrubber:

5. Adjustable fuel pressure regulator: Add more air, add more fuel. Raising your fuel pressure on late models is akin to changing jets on a carb.

0 1000 cfm adjregulator.jpg


6. Fuel pressure gauge: for proper fuel pressure tuning. I set mine to 15 psi. these are fairly cheap.

7. Throttle spring modification: Removal of the stock throttle spring, and replacing it with a SOFTER old-style return spring(s) will increase the opening speed and improve overall throttle response.

8. Throttle enhancer: Casper electronics has a piggyback sensor that when the throttle is at 70% open, it tricks the computer into thinking it's at 100% open, increasing throttle response. (This product DOES work very well, I have one on my Fiero as well)


0 1000 tps enhancer.jpg


9. Bigger TBI: Stick with the stock one...UNLESS you add an edelbrock aluminum intake with a 7.4 liter TBI with the 2" bores. ( This is just a backburner idea at most)

10.1" Throttlebody spacer : (fits under TBI) will add torque by increasing the intake volume. Swirl-type spacers also help mix the fuel and additional air before it's combusted. Unfortunately, swirl types don't work on CPIs....they're port-injected already. I currently have the helix 1 1" spacer. I thought I remembered seeing a 2" trandapt spacer years ago but, I think they discontinued it. Just a while ago, found out CFM technologies has a spacer that's supposed to allow the engine to pull air/fuel from either tbi bore (if it's a duel-plane), offering a more balanced air/fuel mix resulting in more power. Not sure if ours is a dual or single plane, but it's worth mentioning.

0 1000 supersucker.jpg


Most of these parts , together as a whole and with tuning, should net 20+ horsepower. :rockon:

This concludes part ONE for now..........stay tuned for more.

Thank you

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I over-killed mine because that's what I had in the shop- shorty headers(unknown make) with 2.25 y-pipe into 3" pipe to the Cherry bomb extreme muff., and dual 2.5" out the back. It's noisy as ****, and the wife hates it!
TRUE THAT!!!! It sounds almost as bad as headers with sidepipes on a ASTRO...OH WAIT NEVERMIND! :rofl: just kidding 355, i had to say it cause i have headers with 2 1/2" with 24" turbotubes that goes straight out the back and i LOVE the sound, of course im not running one of the 4.3's..Id say a v-6 with large dual exhaust does sound like a obnoxious v-6 with dual exhaust...my :2:
I agree...VERY entertaining and also a little informative...A+ :ty:
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