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hotrodding the 4.3 V6 (tips & tricks)

197932 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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Not everybody was born with a silver spoon in thier mouth and can afford these kind of complete motors.Kids today are hot rodding hondas because that all they got to work with.It a free country where you are(quote unquote) in the pursuit of happiness.If it makes that guy with the puffed up chest happy I say more power to him.The octane requirement and the computer were designed to defeat performance in these engines.That is part of the hot rodding spirit trial and error learning.Friend of mine had a 71 chevelle he had less than 150 bucks in it.It ran 12.70 in the quarter consistently for 8 years just headers.Stock motor.Computer is your biggest performance enemy on these vans.I posted my speedo and I got a 6 second better 0-65 times than factory. Not spending a dime just tuning the beast.A car/van dont have to be a 9 second machine to be enjoyable to drive.But at least get the performance out of it,it is capable of.Dont be defeated all or nothing.I dont understand that train of thought.If I cant compete in NHRA drags I will make it run as poorly as it was factory.Seems self defeating and sadistic.The purpose of this thread is how to better enjoy your van.Not how/why to hate its engine. :2:
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T.Neff said:
I'm actually promoting people to do bolt on go fast items computer,TBI, and all.Just to spend the money in the right places and know why they did that.Sleepers are not by mistake.They often are well planed smart performance updates on a limited budget.
Got ya.I with that program to.I want my daily driver to not be a turtle so much.
Just for giggles I ran the 4.3 in stock form through the dyno program.Just headers gave it 38 HP.18 percent increase in horse power.I used the worst possible engine combination available.Weakest heads weakest cam.Went from stock exhaust to smallest headers.Just taking the cat converter off was 10 horses.It is comp cams running the dyno test.
I used a TBI intake. Thats what I got.I know it contrary to popular belief but it makes more power than the CPI intake in the program.The heads and cam are why the CPI got more power.94-95 vans CPI and TBI have the same heads I been doing my homework.Checked the part numbers on both.I agree bumping up the fuel pressure best bet for keeping up with higher demand on a CPI.A TBI 350 injectors have more pounds/hour fuel capacity and they bolt right on.On a OBD2 a re-program,head porting [email protected] cam, headers.It not real shabby.On my semi-dyno-tech OBD1 Injectors and ajusted fuel pressure with those parts work well.I been keeping up with the S-10 guys they hot rod these things.Guy dynoed 400 ft/lbs 350 HP with an automatic.Now thats a sleeper with quiet pipes.I am more a Deep bass tone guy myself.Rumble at low speeds and quieter nailed keeps the local constable happy with me.
The mazda 3 makes 167hp with a 2.5 liter almost as much as the 454 you mentioned and that would be 288 horse in our vans.Yes I have a tuning issues with that.I am sure the mazda passing emissions.Any monkey with a wrench could tune a 375 horse 396 and get 500hp with headers it been done a hundred times.Where that OBD1 tuning program you talking about.Oh it does not exist.Replace the computer buy a tuner and program.1000-2000 bucks and you have not even touched the engine yet.Yes I consider that a performance enemy when I can buy a faster car for the money it cost just to tune one.Or buy a carbed 450 hp 383 and stick it in for the same price.The 2 MPG and 8HP claimed computer over carb set up is not worth the money.I can drive a long way on that much money.The 71 chevelle had 135 bucks in it.Ran the number 8 years headers 4bbl 4 speed not that tough to do hang at the strip a day.No it was not in factory trim it had a highly restrictive single exhaust 2bbl 3 on the tree.Glad you brought that up it kinda was the point.Show me any computer car where you can increase performance that dramatically for 75 bucks 10 hours work and some junk most would have thrown away.Yes he paid 60 bucks for it.And for the crack about him needing to go to jail.Nobody ever said he was doing 165MPH late at night coming home from work.Beside you said it was impossible so I guess he safe. :whistle:
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I am not even saying thier not better just expensive.To the average joe it cost prohibitive to do anything at all to them to increase performance.And as it has been said so many times on this forum it just cheaper and easier to stick in a V-8.Since we brought up superchargers.My brothers monza had 900 dynoed RWHP with a carbed 383 and a 6-Speed and 20lbs of boost.21 MPG and I garentee he had alot less in it than either factory supercharged car you mentioned.Theres an apples to apples comparison not an apples to oranges.I am more concerned with performance than mileage a few miles per gallon difference wont kill me.The van already gets the same milage as my chevelle.His charger in my album has a wicked 440 ready which will be also a carbed supercharged car.We will see soon what the milage is with the OD I am sure it not great.Even after restoration and motor it still alot cheaper than his next door niebors non supercharged camaro which has 400 hp I think the dealer said with the modifications they did.His 2004 GTO got 26MPG ran a 13.My chevelle when done will run same range high 12 low 13 get 20 MPG even with its rediculous cam.Cost 15 grand less to build and be worth the same thing when it done.All I am saying is for cheap performance gains you cant beat just cranking the timing and changing a cam and jet in the carb and headers.Seconds faster time for 300 bucks if you know what to buy.Those days are gone I know it as you pointed out.But that dont mean I have to like it.
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As usual I know your right but I really old and hate to let go of the muscle cars.I grew up in it and I love it.Thats why I got the van I drive it right now while I do my car.So go ahead just kick an old guy when hes down I can take it.I am starting to play with the computers and I do need to break down and get me a laptop OBD1 and 2 cable since it obvious I stuck messing with them the rest of my life.I just hate seeing the dinosaurs dying out.I in a circle of muscle car people there are 8 like new cars in my family already and many more have passed through our hands.Then there are friends cars like the El Camino which was in the background of one of my chevelle shots in the album.We are doing our best to keep as many dinosaurs alive that we can.The garage my car sits in devoted to them.No new car ever sits in there unless it a major mechanical emergency.And there a 67 lemans in my house basement waiting its turn to be restored as a GTO clone.My car will have completely new interior by the way and it is not cheap.I am over it back to playing with the vans.And when they get old I will be fixing them forever saving them from the crusher.
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Phantom said:
chevymaher said:
As usual I know your right but I really old and hate to let go of the muscle cars.I grew up in it and I love it..I am starting to play with the computers
How old are you ? I was thinking you much younger than this old guy :mrgreen:

You got a car in your basement? is that like Prince Albert in a can ? :rofl: :rofl:
I am 50 and not getting younger quick.Yea I got prince albert in the basement.One car foundation garage and this car 90 degrees to the door.Now thats an adventure getting it in and out past the post.All I can say is wheel dollies and a good thing it only going through the door twice.Once in and once out.
I with ya on that pontiac motor.Personally I over rev them and blow them up quick I had some fire chickens in my day.I could not keep a motor in the 67 to save my life.It had a 455 gran prix tunnel ram engine it it last.And after I finnished that one off there was only two pistons left in the cylinders.Good thing this car belongs to a 16 year old girl maybe it will last longer.Send that motor formula to me.If you look in my album the pic with the lemans in it.The 400 poncho on the front of the trailer.It was supposed to have run a high 10 in another GTO.We looked it over it a sound motor with those 6X heads on it.Dont know what they came off of size wise.My 67 bird would lay twice as much rubber in each consecutive gear with that 455 3 on the tree.Oddest thing i ever saw.Think G forces were starving the jets in lower gears.Engine never made it long enough to be straightened out,Jet extentions and what not.It made it 2 weeks I spun a bearing on the freeway in second gear,was far from home.She jerked down and barked the tires.Then tick tick tick the rest of the way.I knew she was through I had done it to pontiacs twice before.And it grenaded next day but it got me close enough to walk home.Yea I was young then and a hothead to boot.When it starts hammering turn it off dont nail it in the next lower gear till it locks.That chunk of cam that wedged between the crank and block did it in.
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T.Neff said:
We posted at the same time.Many companies out there to upgrade to a EFI on older vehicles.Just saying..........
I read your post and agree.But I just crotchety because I know my van would run alot better if the factory computer would stop pulling off the timing,when it hits 200 degrees or the air on.I got it running alot better than it should already tricking the computer as I call it.But I just hanging in there till the chevelle finished being a money pit.Then she getting some serious power upgrades of some kind.And I will get a front wheel drive granny car to whine cry and moan about because I cant stand weak cars. While the van getting its due and returns to be my daily driver.
Yes I know all that now.But when I was a kid I had a high horse 327 then a 283 so I was used to spinnin them hard.I had pontiacs later in life and never blew them up.My first big blocks they bit it pretty hard.The 327 going into the chevelle a good motor.Rebuilt right to be beat on.Plan is once that done get the van a real motor.Supercharge the V-6 or a V-8 I cant make up my mind.Then back to the chevelle a big block and overdrive.Tag team event.By then mine and my brothers cars done and we will start working on the girls cars who are lolygagging around more worried about teenage girl things at the moment.They saving thier money for parts well, but the working on them got them flabbergasted so far.What mean work, speaking slowly with blank stares.They know we will do it if they fart around long enough.I mean really we would be bored to tears without something to play with.

T.Neff Okay atta boy.I have studied that stuff in depth but I always have run carbs so far if possible and a HEI.I got alot of dinosaur parts laying around and they do work pretty well.It just has not been cost effective to switch over for me.I got everything here just need block and internals big power fairly cheaply.If I go computer controlled I starting at square one.What in the car or van not worth a nickle for the power levels I like to play with.So I would have to buy everything new.In the future I imagine I will have a junkpile to pick through like I do carb stuff.Once these things get older or get crashed and I can pick up on some stuff that way.The higher horse parts.Or I break down and buy what I need.Then I will again be back to replacing internal parts when I destroy them.And servicing the other parts that dont get destoyed in a missed shift boo-boo.
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Phantom said:
chevymaher said:
The 327 going into the chevelle a good motor.Rebuilt right to be beat on.Plan is once that done get the van a real motor.Supercharge the V-6 or a V-8 I cant make up my mind.Then back to the chevelle a big block and overdrive.
Why not save some money and time , put the 327 in the van , and put a Big block in the chevelle the first time :dance:
You dont know how many times I wanted to.But the chevelle been apart not driven for 3-4 years.When it painted I want to drive it.All the parts there just needs put together.And I want to pop that hood on the 2X4bbl intake.That would never go in van single 4bbl I am not taking off that engine cover constantly to ajust them.They are cool and a pain in the rear to.At one point I wanted a 502 crate motor for the van.My brother said how much power you want in that thing.Get your chevelle done first.Tim the tool man Taylor syndrome to much is never enough.That was about the time I joined this forum.I knew very little about the vans then I just drove the thing dog that it was.So I hot rodded the V-6 to tide me over.
drmmhmd said:
I have a Monte Carlo stranded on the second floor of a shop for 11 years, they put it up there and then their care elevator broke. no rush
Sweet what year monte.Wow this getting way off topic.We getting a runnerup spot on the cupholder topic.And I seeing a common connection with us van lovers.All hot rodders from all different disciplines of cars who found comfort in the vans as drivers.Now just kick me in the family jewels tell me to stop being all philosophical and whatnot sit in my van and think about what I just said. :whack:
Place is hopping tonight sorry I late for the party.

EGR Block. Electronic doesn't need the ceter hole only the bolt holes.

EGR Block.jpg
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andrew728 said:
That was fast !!!!. Lol. One last question. How think is the aluminum piece? I was thinking it was going to be 1/8" thick but yours looks like almost 1 1/2"
Mine is made from 1/8 inch steel. I used a furniture bracket. Cut, drill, sand smooth. Installed with 2 gaskets one on each side. Mine is a electronic. The pic is from making one for my customers truck. But it made from the other half of the bracket. Waste not want not.
WoodButcher said:
Yeah CM, you're gettin' slow in your old age,,, 14 min. Did your walker break down?
Last night checking in new post, reading post, it was jumping.

And yea I've fallen and I can't get up. My little button was just out of reach.
andrew728 said:
I have been looking and can't find it !!!. I am looking on the passenger side. I replaced the Dis.Cap and rotor and wanted to take care of this while I had her open.
Your looking for the EGR?
I been hunting a picture of one. It a cylinder on your year. 6 inches long and 2 inches in diameter.

What is your engine vin? X didn't have one.
Okay that solves that yours doesn't have a EGR. A vin search will tell you the vans options it came with. Unfortunately the free searches got greedy and want money for it now.
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