IronBelly

A coworker of mine has an 88 firebird formula 350 TPI and I have an 89. From what I can tell they are pretty much identical, mechanically speaking. His is a little beat up and rough around the edges. We both have aftermarket exhaust, mine being Edelbrock ti-tech shortys with custom built 3", no cat and edelbrock SDT muffler. That's where our aftermarket similarities end. His list of mods is as follows: hooker shorty headers with flowmaster 80 series catback. msd ignition coil, cap, rotor, superconductor 8.55mm wires. Jet performance 180 degree thermostat, 180-195 degree fan switch, and stage 2 chip. Of course I can't forget the K&N air filter. He thinks these few little add ons make the world of difference and that he would blow me away at the track. All in all he says he spent about $350 on all of it, not including exhaust. My question is how big of a difference would they make? I wouldn't mind spending that much if it gets me a little bit of a boost in power, or is it not worth the money for a negligible difference that won't be felt when I put my foot down. I've read a lot of different opinions about some these add ons but nothing quite answered my questions/thoughts.

86Z

iTrader: (4)

i don't think all that will make a big difference, the chip is probably adding timing...

throw a cam in your's and a custom tune

BadSS

I used to do "super tunes" back in the 80s - porting the plenum, cutting out the air box on the Zs, adding K&N filters, home made ram air with dryer ducting, adding an adjustable fuel pressure regulator, and adjustment to the throttle position sensor and timing would make a considerable difference. I never worked on a single Pontiac TPI, so I don't know what if any benefit the K&N would be over a fresh filter (my guess is not much).

Nothing the other guy has done would make any significant gains assuming you had a new air filter and ignition system is in good condition. Yours would probably run just as fast as his assuming the same gears and condition of the transmissions are comparable if you ran premium gas and bumped the base timing to 10-degrees - that and making sure you're as close to 5volts as you can get it (anything over 4V is "OK") at the TPS under WOT. I've read a couple Jet chips and about all they do is jack the fuel up a little (no better than increasing the fuel pressure with the stock chip) and add a little timing.

TTOP350

iTrader: (8)

Buy a 160 t-stat and proper fan switch then install them.
Modify your maf and air filter housing
Do the old school ram air trick, raise the pass side headlight and remove the bezel and light, lower door about half way.
bump your base timing to 10-14 degs an run 93 octane.
buy a fuel psi regulator and bump it up to 48-50psi. You'll have to find what works best w ur car for timing and fuel psi
since you are a maf car, you can unhook the knock sensor with no light. Only do this if you understand the knock system and what it does/doesn't do properly.
Have a good shift kit installed and a mild tq converter (one from a 4.3 S10 works decent).
These are all budget things I did back when these cars were new. My car flew compared to a stock one.

fervernt

ok not that I condone street racing, but wouldn't a good way to see how much of a difference these upgrades make be to line up at a light and see what happens? I mean it wont give you numbers, but if he destroys you at a light it would answer your question on if they make a difference lol

IronBelly

What modifications would I do to MAF and air filter housing? I understand what a knock sensor does but I don't understand what the benifit would be from disconnecting it. Could you elaborate? I think for now I'll start with a cooler thermostat and fan switch just to keep the heat down. Summers here can be rough and sitting in traiffic it runs around 230-240. The second fan doesn't come on until about 240. I don't like that. I'll probably tweak the timing a bit too. So simple and I didn't even think of that.

BadSS

Take off the screens, use duct tape to cover/protect the internal element (both sides), take the blade loose on a hacksaw, feed it through the MAF sensor, reattach the blade and cut out the fins. I then take a dremel and smooth things out,, clean it up and take off the tape.

This is the best picture I could find.


Here’s a link to porting the plenum.
http://www.gmtips.com/3rd-degree/dox...-port/port.htm

TTOP350

iTrader: (8)

The knock sensor sees a lot of "false knock", when it does, it pulls timing and is very slow to bring it back to full timing.

I'm going to be starting to do a complete writeup on my friends 100% stock 70k mile 89 formula 350 in the next yr or 2 as to which mods add what kind of power...

chazman

iTrader: (4)

That'll be interesting!

I did most of the cheap/free mods on my '89 back in the day, and although each one individually didn't make a big difference the combination of all of them really woke it up.

TTOP350

iTrader: (8)

I have a very cool road test from back in the day on a new 89 Formula 350 that they did a bunch of stuff like this.

no new tires

Don't do that...not worth possible damaging a $1xx dollar sensor for no real gain.

TPI

Definitely do not descreen or cut the fins out of the MAF, there are far better ways to make these engine run quicker. Cam/tune, ignition and a CAI will make the car move, if you want more.. Stall, and gear it. But then, traction will be your next enemy.

BadSS

Descreened and cut out the fins on at least 12 different MAF cars over the years - never damaged one and no one ever experienced a problem from it. Probably won't see much if any gain if you don't do it with other mods (increased air flow before and after along the MAF with an AFPR or tune), but every little bit adds up with these TPI cars. Obviously if you or anyone else is uncomfortable or scared to take it on,,, don't do it,, or any other mod as far as that goes.

TPI

The guy is talking about very minor bolt-on's and people are suggesting de-finning MAF's? ...really?

Apologies in advance, but I say no. Get the car to run cooler, jam cold air down its mouth, get some solid spark. Don't kill the drivability of a already fun to drive car!

no new tires

Truth

BadSS

Again, this is a mod unless your comfortable doing,, just don't do it. Yes there are other things you can do, but this is definitely one that works (there's no denying it increases airflow).

I didn't suggest it, but he asked - Truth?

Killing drivability? Really? Seems strange I've never seen any drivability problems with all the MAF cars I've modified. HOWEVER, I've always added an adjustable fuel pressure regulator (back in the day) or tuned for it (once the hardware and software became available). So maybe this is something that everyone can't handle.

IronBelly

The link above has a lot of tips and mods that can be done for free. I would definitely not take the screens off the MAF. There's an excellent article at said site explaining why. Thanks for everyone's input. So as of now this is what I'm going to try: a good tune up with msd cap, rotor, wires, and 48k volt coil, set timing to 10 btdc, jet performance 180 thermostat and 195-180 fan switch, relocate MAT, port the plenum, spark plug mod, throttle body coolant bypass, and cutout holes in bottom of airbox. The full list of all these mods can be found here: http://www.gmtips.com/3rd-degree/dox/tips/tips.htm I don't expect huge gains from this but overall I think it will help with throttle response and drivability. Any input on these ideas or anymore ideas for more free or cheap mods that will wake it up? Would an AFPR be needed for these?

TTOP350

iTrader: (8)

Not a thing wrong with d-screening or d-fining the maf, have done it to all my cars and many many of them through the years.
Also picked up a bit of power, even on stock motor cars, some I even dyno'd and proved.
I did finally lose my original maf at 220,000 miles.
If they go out its due to the crappy electronics in them, a bunch of them died when they were brand new.

Fast355

iTrader: (2)

I agree, I ALWAYS DESCREEN the MAF. On my 2014 Titan the maf is simply bolted into a tube. Stock was about 3.25" ID, it now sits in the middle of a 4.5" ID tube that feeds from a 6" filter. HUGE difference in power over the stock setup with the right ECM tuning.

I have actually built my own 4" TPI MAF housing using the stock guts without the screens on a car that had a 450 HP 383 in it. Rescaled the MAF tables and down the road it went.

Ultimately all engines like a good healthy supply of cool air.

TPI

People have different ways to go fast, and in this regard I just advised against it considering what he is trying to accomplish.

The story would be alot different if the said engine was a 383 cammed and headed monster starving for every little molecule of air! In this case, the gains would be negligible to risk a $200 sensor.. Definitely not saying anyone's advice is poor, just to clarify. Sounds like you have a pretty solid course of action, have fun!

Orr89RocZ

iTrader: (20)

Gut the camaro style air box filter bottoms and run ducting to grill for ram air. No dyno or track results with descreening maf here, but it certainly did NOT hurt anything about the car.

Ice the plenum at the track between runs. Warm motor ice cold intake plenum was worth a tenth for me.

Then all the basics, ud pulleys, exhaust, play with timing. 8 deg base worked well for me. The motors already see 34 deg of timing stock so 2 more degrees gets them as far as they seem to like on 93. I had seen some knock counts at 36 deg and ran 35 when i did my chips. The better gain is altering shape of timing curve. Not sure if the jet chip does that. In the past i heard they were junk, not much changed over stock

I cant see his mods being much different than your car unless your ignition components are old and not working

chazman

iTrader: (4)

I've never de-screened the MAF. I know others have, but just something I didn't want to do. Gutting the Camaro airboxes is another great free mod.

IronBelly

Agreed. I found this on gmtips.com. This explanation makes sense to me.


"The Myth: Across the internet and word of mouth spread the news of this "free mod" and countless pages promoted the technique of MAF Screen Removal without considering some very basic theories and the potential harm of doing this mod. Consequently time after time you will see the post and topics "I removed my screens - now Code 33".

The Fact: The MAF Screen Removal Process WILL NOT CREATE horsepower within itself. It can only in the right conditions FREE UP horsepower that ALREADY EXIST and only under certain conditions.

Why?

1. Your stock MAF with screens will outflow your stock 48mm throttle body.
2. It will even outflow a 52mm throttle body.
3. It will also outflow your stock intake.


This Means: that if you are still using these stock components your MAF screen removal process is totally wasted and potentially (code 33) dangerous and could cost $100.00 + if you screw it up. The MAF has to be the most restrictive element in your chain of flow to even possibly make the mod worth anything and ONLY if you already have the horsepower to free up by a modified throttle body and intake."

TTOP350

iTrader: (8)

He also said they were his
Opinions & Theories:

It is your car, you should do as you want! Use all the info you can, make a plan and go for it.
You'll be back tho, wondering Y the guy in the other lane with mods that someone on the net said "don't work" walked away from you.

Fast355

iTrader: (2)

NOT EVEN CLOSE....

A stock 48mm TB without an airfoil is 783 cfm corrected for 28 in/h20
A stock 48mm TB with airfoil is 822 cfm
A 52mm TB with airfoil is 899 cfm
A stock Bosch TPI MAF w/ screens is a wheezy 518 cfm
A descreened MAF is 658 CFM

http://www.gmtuners.com/flow/index.htm

chazman

iTrader: (4)

Hey, interesting link!

I wonder what the stock airboxes flow compared to the gutted ones?

TTOP350

iTrader: (8)

I think its in TPISs "insider hints" book. They flowed several intake combos and just the parts to see what flowed what.

chazman

iTrader: (4)

You know, I have that book. I haven't read in over 20 years.

Wonder how long I need to be in the basement tonight to find it.

TTOP350

iTrader: (8)

Mine is in my file cabnet with ALL my service manuals, engine building books and old catalogs!

no new tires

TPI nitrous kit

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