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hotrodding the 4.3 V6 (tips & tricks)

197963 Views 190 Replies 52 Participants Last post by  sixsix
5
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. 🍌 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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We posted at the same time.Many companies out there to upgrade to a EFI on older vehicles.Just saying..........
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:
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.
chevymaher said:
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.
Yea a good set of dollies works wonders

I 55 :eek: When you get around to building the motor for the Pontiac I got something for ya ;the 400 and 455 Pontiac engines are a couple of the best engines there are , I have had several and still have much documentation to get 500+ HP from a stock motor with just a few mods , and the torque is at an unreal number over 500 as well , When I get a flatbed scanner installed here I'll scan them for ya and send them to ya, The first secret that comes to mind that can give 30+ Hp with just a swap is to find a set of 6X heads from a 350 cu in Pontiac and bolt them on a 400/455 there are 6X versions that came on 400/455 as well , it's important to get them from a 350 because the chamber is smaller and raises the compression a full point , so simple swap and big benefits :layrubber:

and also find an aluminum intake from a 68-69 -73 factory HO Firebird or GTO they are the equivalent to an edelbrock Performer Series intake for less than 1/2 the cost
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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.
Wow you are real hard on motors ,,, is there super cement under the pedal that refuses to let go of your foot? :lol: :lol:

In most factory cars the Big Cubic motors are designed to achieve max power at or near 5000 rpm, and often at 4500-4800 rpm , never any need to go much above 4800 , , Now the Big cube motors can be built to go to 10,000 rpm or so , it just more expensive to build a Big cube motor , small blocks are well known for the need to hit really high rpm in order to make real strong power , and some people make the mistake of thinking Big Cube need to do the same , it is not needed. Actually running at really high rpm is where the wear and the increased heat comes from , breaking down oil and breaking parts ,high rpm is really hard on any motor which is why the factory wanted motors that could make more power at lower rpm , because for everyday street use is performed in the low rpm range , no need to go 5000 rpm in 2nd gear just to stop a a red light in a few blocks . I have had 5 Trans Am and 2 GTO all in the 70's years and have taken some of them to the track and raced them all year long , The last one I had owned it for 10 years , raced it hard for 10 years and I have never spun a bearing or had any serious engine problems in any of them Pontiacs , now I spun bearings in a 2 fords with 390 cu in motors , threw a rod though the oil pan with a 350 Chevy , but never in any Pontiac I ever had , I still have some Trans Am parts in storage for the next time i get one :mrgreen:
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T.Neff said:
The TBI MAP sensors do not like performance applications.Those need to be adapted to MAF sensors.There is a company the eliminates the use of chips in obd1 systems as a piggy back system and there for no more back and forth for a chip burns.In the link click on the different sections to see how it works.

http://www.dynamicefi.com/TBI_Fueling.php

The computer systems are sensitive to cam profiles in this way.Not much over 230 duration and really not much below 112 cam lobe centers-114 being better.

It is still to purchase a really good system like Edelbrock Pro flow very expensive.The Fast systems will nickel dime you to death once you have bought all the parts and Holley Commander 950's are still in the low $2,000 once you have all the parts.

The balancing act in tuning is to not have a over rich idle and still have enough flow for the top end.Remember these injectors have to be able to cycle fast enough to supply fuel at the top end.Some guys go for a enlarged injector with a increase fuel pressure knowing the injector doesn't have enough time to fully cycle and ends up almost consistently flowing fuel at higher RPM's.Of course they need to add a regulator to that.You can and should enlarge the bore size on a TBI to pick up more cfm.Much of that size is dependent on the selected cam,C.I., keeping in mind these EFI need a good vacuum signal to work.Still the above link requires a lap top for tuning.The weather conditions and the where you are with the vehicle does come into play in the tune.So you never get to cut the USB cord so to speak.

I am a fan of the SFI's because of the more exact fuel management and know the trade offs because of the design of the system.
Gezzzz. :banghead: I thought I would get a thad-a-boy or somthin. :shrug: Before you say it-I agree,it is pretty bad when you quote yourself. :whistle: Just wanted to get on the current page for folks to see it.OK??. :thumbup:
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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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:
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 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
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:
thank u for your tips . in my van i notice that the passenger side manifold vacuum hose block with a screw in a little peace of hose and i know it is wrong can u inform me where it supposed to be connected to please .i have 1992 safari TBI
My first post here.. but I've been lurking and modding these vans for years now and have more than a clue to their main weak points.

So, with that in mind there are a couple of things I would add for those doing low budget mod's on these vans.

1. Mod the factory TB air-hat to provide a larger(less squished) plenum above the TB's bore. GM squashed the hell out of it thinking that you would need to access the thumb-screw for removal from the front of the engine bay(underhood), whereas most who are going to that extent will just remove the doghouse anyways. I easily added about 1.5 inches of height to the airbox's plenum when I chopped and glassed mine. Smoothing the radius's on the interior with epoxy filler didn't seem to hurt airflow either. Combining that air inlet mod with a modded and/or bored TB can increase the gains from the TB mod's alone even more. One improvement just brings out another's weakness, sort of thing.

2. For those of you who run cat-back's. The factory y-pipe is very restrictive internally in the design and workmanship of that exhaust split. All you need to do is cut the existing Y out and fabricate(or mod a pre-fab'd unit) to take its place. Then once you have the factory transition removed?.. take a peek inside at the irregular/very sharp protrusions that had been previously interrupting the exhaust flow. I have pic's, and trust me.. it ain't pretty from an airflow standpoint. An easy and conservative 20-30 CFM gain to be had by all.

3. Be VERY wary of muffler choice.. especially in kits, and even more so for those which only include single mufflers(dual outlets will not make up for poor internal design and/or those which are hastily built. And always remember.. even shiny high priced polished mufflers can flow less than a cheapy painted one. In fact, with many kits exhaust flow and overall performance is often traded for sound and/or those shiny stainless "I'm a big boy" looks. Obviously we need to balance the want for power with the need for quieter non-reverberating sound waves banging around inside our "cool tin boxes" as we cruise down the road. Chambered mufflers are quieter by nature and therefore more restrictive by inherent design requirements. Straight through/baffled designs are generally more powerful(although they too can have internal design flaws which contradict this basic rule).. but they often trade for long term hearing loss that you may have wished to avoid in the process of trying to sound so cool. Most muffler mfgrs have flow charts available and it's always best to do your homework before buying Pre-Fab'd kits or building your own custom system. Because even on a near stock vehicle a bad performance muffler choice can easily cost you 15 horsepower and 2MPG over a good one.

4. Headers. Last I looked(which has been a while).. there were no Astro/Safari headers for 4.3 motors. Some are modding the S-10 or even V8 headers to fit but I actually found it cheaper and more effective to custom build my own from end to end(with the prerequisite EGR delete of course). There are more than a few suppliers of V6/V8 flange kits to get you started and the overall results are far better than the little tightly radiused shorty kits. Long tubes will always rule on a street engine and once the pipes are merged below the frame.. longer/smoother collector transitions can help the airflow cause even more. Some builds(those with cams)/usage scenarios(towing) would be better suited to dual muffler cofig's whether they be dual or ganged in single pipe arrangements. Using more mufflers in parallel makes the use of cheaper/lower flowing mufflers with smaller internal tubes/passages more realistic for those still wanting upper end power gains. Duals/ganged setups are often quieter as well.

Exhaust work is not so much about peak flow, and more importantly has little to do with the all too commonly thrown around term of.. "back-pressure"..(although some "stock tunes" obviously seem to prefer less exhaust flow), but is generally more about controlling the velocity/scavenging effect at various airflow levels(which would normally be a derivative of RPM or power adders). Maintaining the smallest possible diameters/transitions without creating too large of a choke point at any given location in the system is the key to keeping your lowend while not giving too much away on top. Higher average torque numbers over the typical operational RPM(especially with stock cams) will make the truck or van that much more enjoyable and responsive to drive with the added benefit that the gas mileage increase will help pay for the mods faster than most may realize.
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astro355 said:
Yes but the exhaust would have to be done right. True dual exhaust for a 4.3L would make it run worse. The exhaust flow would decrease because the exhaust would cool too quickly and slow down in the pipes. You would need a X-pipe at best to help with the scavenging and maintain some of the heat. The same thing would happen if too large of pipes were used.
Where did you study flow dynamics? Your statement that the exhaust would cool too quickly is TOTAL B/S!
Temp has nothing to due with it -- pulse speed is the bug-a boo. An "X' pipe or an "H" pipe helps balance the flow,
and helps prevent backpressure caused by standing waves. Pipe that are too large cause pulse cavitation with the
gases bouncing from wall to wall, causing backpressure.
Go read some of David Vizards articles on flow bench testing!
ok, so ive been reading thru this thread (as well as a few others, and i have to say that while i really do appreciate the amount of effort that went into this, its nearly caused me a brain aneurism! there is a lot of good info on here but it is completely diffused by all the zippy side commentary and incessant use of these goofy little emoticons :screaming: :screaming: :bouncy: :banana: :bow: :confused: :wave: :ty: they render the whole thread almost completely un-followable!

whats wrong with some nice clear CONCISE basic info?

i have a few basic questions that have led me to many hours of google dead ends because the info provided did not apply to my Safari (its an 03 btw)

may i propose another sticky thread with some general basic info? such as but not limited to...

1 the basic difference between "W" and "X" motors (or any other relevant ones)
2 the difference between t.b.i and c.p.i. ( along with helpful data such as which came on what years etc).
3 OBD II? OBD III? IV? wtf is this??? it is referred to often enough that i know it matters, but do i really want to search yet another term just to find out it doesnt apply to my van?
4 any other relevant distinguishing information that would allow a 4.3 noob to do some quick research, so they could then possibly search out the threads that might be useful to them?

i realize i can search all of these separately, but what worries me is, what are the terms i havent stumbled across, that might really matter?

i read ALL ABOUT the cfm technologies spacer that is supposed to help with airflow and bake you cookies when youre asleep, when i finally looked up the company "oh great! doesnt apply to my van, perfect! i just wasted 2 hours reading about this thing and their throttle body spacer that also doesnt apply to me either.

i really hope im not sounding like a whiner here. it really just seems like it should be easier to find some basic fundamental info, and lay off these feakin things!!! :banghead: :whack: :bouncy: :wave: :whistle: :ty:
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Thank God for that good ol' nog00der bcuz i have no idea what the hell these seasoned vets r talkin about. Now to add on if someone could please explain those four questions by Mr. nog00der, excellent questions by the way us astro newbies would greatly appreciate it.
IMO the trouble with trying to make those three questions above into a sticky quicky is that they simply are not "quick answer" questions. Throw out the 4th question, it's not a question and essentially covers everything in the AstroSafari universe.

On TBI/CPI for example (and there are others besides those two)...That's basic stuff that I need to know in order to do nearly any kind of maintenance, tune up etc on my van. There are literally thousands of web pages on TBI alone. Trying to distill that down to a paragraph for a sticky would surely lose a lot in the editing.

TBI is Throttle Body Injection
CPI is Central Point (port?) Injection

That nearly expands the abbreviation. It doesn't go into the huge body of work, discussion, arguments about the pros and cons and how to work on either style injection.

One sure fire way to make a reference like that materialize is for YOU to build it.. :thumbup:
Go look up the answers, do the research, distill the information and put it into a form that you think will be useful.

I would suggest that anyone who is at the stage of wanting to "hot rod their 4.3" should probably have a very, very good working knowledge of what all those terms mean. More knowledge than might be gained by reading a short sticky.

All the information is out there. Heck, it's all in here! It's in hundreds of posts complete with diagrams, drawings, photos, part numbers, web links. All specific to not only 4.3s but to our actual vans.

Lump
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In order to find concise info about your van the best source is the FSM, (factory service manual). You can find them on fleabay.
What I would suggest is to start your own build thread and look for feedback on ideas there. Any hotrod thread posted here will likely be on that one van, like lumpy did with his lift or chevymaher did with his rebuild. (those are two gifted pups right there!) (lumpy picks a mean guitar) :rofl:
Max attempted a general guide but there are so many variations over the years and differnt ways to get from a-z so you get this- :banghead: and then turkeys like me add our :2: and you get this- :blah:

I would encourage all new guys here to start a thread on their van and in that way you get the feedback and share the wealth of knowledge you pick up along the way. If you do a write-up of one specific task with lots of pics I'm sure it will get stickied, If you gather the info on hotrodding the 4.3 v6,,, It will be sticked, don't forget the pics.
Lump doesen't sleep well w/o is daily ration and then goes out painting camo on everything,,,,
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