I accidently posted this on the TBI board, but i didn't get much of a response anyways, so here it goes.

I'm going to replace most of my ignition system in my 1991 RS TBI. Here's the list

MSD 6A Ignition Module
Spark Plugs (platinums??)
MSD 8.5-8.8 Wires
MSD Blaster 2 Coil or Accell
Cap and Rotor (Accell)

What kind of gain can i expect on my completely stock TBI? In terms of HP, torque, 0-60 MPH and 1/4 Mile times.

Would an adjustable fuel pressure regulator make a bigger difference if i have a better ignition? I plan on doing this small project afterwards.

FYI, I also plan on a K&N open element (more spark needs more air) with Dynomax exhaust+CatCo on top of all this.

 

You may add some HP and Torque, but overall you'll just have a betterignition. You'll see improvements in starting, and idle and through the RPM range.
Sounds like a good setup. You'll like it.

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350 4 bolt main, Speed-O-Motive 383 stroker kit, re-sized rods ground for clearance,TRW Forged pistons,10.7:1 compression,HPC Coated RPM intake, Speed Demon 750 cfm carb,World Products Sportsman II heads,2.02/1.60 valves, Comp Cam 1.6 roller rockers, Comp Xtreme 284 cam,240/246@.050 with .540 lift,Crane pushrods,ATI damper,Proform HEI and MSD6A box,HPC coated 1 5/8 headers, 2.5" exhaust with 40 series mufflers,TH350 with B&M 3000 stall, Powertrax NoSlip Locker, 4.11 gears.

 

If your car is relatively stock, you will notice better idling and smoothness of throttle and other small stuff. Until the car is totally unrestricted (well, as much as possible) with a freer flowing exhaust, and intake, not much power will be realized.

I just like to take care of the basics before doing little stuff though. Must be just me.

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--Steve S--
1984 Trans Am 305 LG4, 5 speed
Daily Driver, Flowmaster 80 Series

 

I hate to burst your bubble but you will not realize any gains except for imaginary.
#1- plugs/wires/cap and rotor are tune-up items. No power here unless what you have now is shot.
#2- Ignition amplifiers are WORTHLESS on cars that are anything but heavily modified. And by heavily modified. And by heavily modified, i mean, big compression, blower or juice. HEI has no problem igniting your 170hp TBI. If your tuning is way off, it might help some, but it'd be sidestepping the real issue of your tuning being way off. You'd make more power by having your tuning dead on.
#3- even the coil is a waste on a completely stock engine. Since they're pretty cheap, they're worthwhile if you have some mods and are spinning well past 5k frequently, as teh stock coil will start to fall off in the upper 4k range.

Instead of wasting $150 on the box, use it for real mods, like start saving for a full exhaust. Or buy a cam and a dremel.
And don't buy thos ehigh dollar wires. They are not gonna be any better for you than any generic 8mm wire. Accel wires have never given me problems, and with the moeny you save here, again you can save towards real mods. Or hell, stock up on M1 for your next few oil changes with the money saved, i guarantee you will get more from running full synthetic than those wires would give you.
And don't buy platinum plugs, the platinum tips have a greater tendency to retain heat, and thus cause detonation. Their only merit is that you can go longer without changing them, but personally i'd rather change my plugs every so often juust to keep an eye on their condition anyway. Also, do not waste your money on any gimmick plugs (splitfires, rapidfires, jomamafires, etc), they hold no value eiether exceot the placebo effect. Don't believe me...take apoll on this site and see how many serious cars use 'em. I doubt you'll find anybody who runs better than a 14.5 who says he thinks they're worth it. And i try not to take advice from slow cars on how to go fast. The most knowlegeable EFI guys on this site tend to run autolites (cheapest plug you can get) so they can change 'em and read 'em often. I ask you again...who do you take seriously, guys who are running 12s and doing all their own work, or guys who are 2 tenths better than stock who throw money at their car to think it's faster.
...ed

 

good call Ed,
I second that post

 

I agree with Ed on everything but the Accel wires since I've had quality issues with them . But that post was full of good advice.

 

Accel Wires suck

 

Finally... Thanks for the answer guys. Every time i search or inquire about this subject i get two completely opposite answers. HUGE gain or little gain, sometimes no gain.

From all the answers i've collected it seems the only things that may be remotely worth it is a set of thick wires and possibly a coil. I will be upgrading my engine as i go along, so i don't plan to keep it stock. I'm gonna do the AFPR project which i could prolly make use of the coil with.

That'll save me about $160 I was about to throw out the window. I'll buy an STB with that.

Now to settle this K&N issue....

 

I did my MSD 6AL box and Blaster SS coil because I was running out of mods.. There's not too much to do to a 2.8, ya know. I did some testing though, with a coil upgrade and a wire upgrade, that you might find interesting! Remember now this info's for a 2.8 Multiport-injection, I don't know if it'll be representative of your 5.0 TBI.

Stock coil vs Accel Supercoil: The Accel Supercoil gave me some more push in higher rpm's. The trans also shifted later, but I think that's because the engine had a bit more power.

Cheap 7mm wires ($20) vs MSD 8.5mm's ($70): The engine seemed to rev up faster with the MSD's. With the cheapies, the car took a while to get off the line.

Accel Supercoil vs MSD 6AL/Blaster Coil: The engine takes a second or two longer to crank with the 6AL box on. I've noticed that my pinging has gone down, and strangely enough, the gasoline that my car used to hate (Sunoco) is now the brand that it runs strongest on!

If you want more convincing, look at the newest Hot Rod magazine. They upgraded the old-school "points" distributor on an old Chevy- and put the car on a chassis dyno for a before/after comparison. They noticed no gain in HP.

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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

[This message has been edited by TomP (edited February 16, 2001).]

 

Wheres that MSD Tech guy when you need him.

 

What K&N issue? The only one i can think of is this...is it worthwhile...YES.
I do not believe you'll see any gains from the filter itself. The advantage is that you can clean it often. And a clean filter will make more power than a dirty one. True you could buy 10-15 stock filters for the cost of a KN, but it's a small enough investment that i don't think (gains/$$) matter much. If you're looking for max power, save your money. If you'd like to be able to clean your filter every other oil change w/o buying a new one, then get a KN.
...ed