What "free mods" can be done to a 305 TPI with speed density. Since I don't have a lot of money right now I'm planning on a K&N, airfoil, and maybe a muffler. What free mods would work well with my planned mods? Are my planned mods worth it? What kind of muffler would you guys recommend? Thanks.

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90 Formula 305 TPI 5 speed.
Bone stock (for now)

 

First, make sure the car is tuned up with new plugs, wires, cap/rotor, all new filters, check the timing, set the TPS, etc. The airfoil definitely isn't worth the money. Unless you can get it for 5 bucks or so. K&N filters are a good start for anyone, but go ahead and cut your airbox. I see that you have a Formula so I'm not too familiar with the airbox on that car. Someone else should be able to tell you exactly how to do it. The muffler is a great first mod. It not only gives the car a little bit more power, it changes the sound of the car. If you can afford a complete cat back kit, go ahead and do that. I'd suggest the Hooker or the Flowmaster catback. Check the tech articles on this site and search the message board archives and you'll find alot of great info.

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1991 Z28 - 350 TPI, T56, McLeod street clutch, LT4 pressure plate, Pro 5.0 shifter, ported plenum & runners, AFPR, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember

 

Free mods=

1) Bypass the coolant flow to the throttle body

2) Cut the airbox open fromt he filter element down. Make it as open as possible while still being able to retain the filter.

3) TPS adjustment. Stock is .54- I recommend going to .60. What this does is trick the computer into going into Power Enrichment Mode at 1/2 to 3/4 throttle.

4) Advance the timing from stock 6* btdc to 8* or 10* (depends on the quality of fuel you use regularly. The higher octane, the more advance i'd give it)

5) Depending on your state's emmissions laws, I'd eliminate the cat converter.

Hope this helps. Everything I mentioned is either free or real cheap (under $100).

See sig for recommended mods.


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Mike L.
It ain't pretty.......

1987 IROC Z TPI 350 A4 3.27 Borg-Warner.

Mods: 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler, 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog

http://www.MichaelLasiuta.home.att.net

**BOYCOTT LAPEER DRAGWAY**

 

What are you talking about when you say "cutting the air box"?

 

Im looking to find an intake and options for my existing one. I was just gonna but a k&n and a new lid but if there is a was i can do more i would liek to know.

 

FOr the Pontiac air intake system, the best thing is to just get rid of that entire air box setup and slap a K+N (or comperable brand) cone on the end of it. You can also try to route a hose down to the air damn and up through the fender that puts fresh air into the filter but just doing the cone will give you a lot better airflow than the stock setup. SLP makes a cold air kit that has all the same rubber intake tubes as your stock setup and a box that seals against the inner fenderwell wher the EVAP sanister currently resides. You could buy the SLP airbox, a K+N for the stock airbox (as it is the same size and works - I had it on my 85 T/A), remove the EVAP canister and related mess (not needed and car the car will still pass emissions unless they do detailed underhood inspections), and just attach it to your stock rubber hoses and you would have the exact same setup as the SLP cold air intake system.

I had that system on my 85 T/A and it worked well. I could really hear that thing when I got on it. I currently have just a cone on the end of my rubber hoses right now but with the engine being so loud, I don't hear the air intake system sucking . I plan on fabbing up a PVC elbow to put my K+N cone into the fenderwell more so it gets a little better air flow.

There are a lot of posts in the archives about this subject and I have discussed it often. Do a search and you'll find lots of different setups.

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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23*, LT4 Hot Cam, Ported plenum and intake, SLP Siam Runners, Edelbrock TES, gutted Cat, Flowmaster, K+N cone, AFPR, TB bypass, AirFoil, !AIR, !A/C, !EVAP, ARAP, 2300 stall, Hotchkis STB.

 

Yea i thought about routing the stock hose tworads the air damn but didnt go any farhter with the thinking. The slp intake soundds good but I dont really have the money for it becasue im getting headers and rims at some point. I'm gonna research the directing the stock hose thing though.

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Chris
-91' firebird V8, 305
-Flowmasters with stainless steel pipes
-B&m megashifter

 

Muffler?? Flowmaster!!

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89 RS

Looking For:
87 IROC-Z28 350 TPI

 

Your sig says your looking for a car?

What would you offer for mine? It needs paint. The factory paint is delaminating (peeling off).

Other than that its nice.




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Mike L.
It ain't pretty.......

1987 IROC Z TPI 350 A4 3.27 Borg-Warner.

Mods: 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler, 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog

http://www.MichaelLasiuta.home.att.net

**BOYCOTT LAPEER DRAGWAY**

 

Do the stuff people have already mentioned:
1) Full Tune-Up
2) TB coolant bypass
3) Port the upper intake plenum
4) Cold-air/forced induction setup

With a Camaro, the forced induction is really easy, cause you can just cut the bottom off the airbox, and run some home A/C ducting down to behind where the foglights are. But on a Firebird, I'm not sure exactly what to do about it. I've got the Speed Density system, so I don't have to worry about the MAF sensor, but I haven't figured out how to engineer this yet. First I was thinking of the SLP kit, but at $269 for the single inlet and $309 for the dual inlet AND relocation of the carbon canister and battery (for the dual inlet), I'm not sure I want to go that route. I was thinking of putting a K&N directly onto the TB, cause I don't have to worry about a MAF sensor, and building, or finding a box to put around it, and finding the ducting to run down in front of the engine and under the radiator to the air dam. But there's not a lot of room to work with there, so I'm not sure that'd work. The other option I was considering was keeping the ducting stock up to the filter, then somehow boxing the filter and cutting a hole through the tray underneath the filter and running some ducting to the air dam from there. Neither option sounds very appealing to me, so I might just stick with what I've got for now.

 

Yea those are the options i was thinking of but there really isnt musch room at all to work with.....

 

What does the firebird THERMAC system do? I dont believe mine works because for some readon its bent up looking like the guy before me had a problem that he took out on it. Do I need it? I've noticed it has another tube going from that system but i dont know what for.

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Chris
-91' firebird V8, 305
-Flowmasters with stainless steel pipes
-B&m megashifter

 

Do you have any pictures of your car? I tried your web page but I couldn't get to it. Where abouts do you live?

 

Since you're low on money, I would skip the air foil for now and put that money towards a good tune up. Your money would be much better spent on something like a good set of wires (ie: Taylor or MSD) and some new spark plugs (ie: AC Delco). For the amount of minimal gain you'll get from the airfoil, you're better waiting a bit for that one.



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1987 Camaro IROC-Z
350 TPI (L98), HyperTech Airfoil, K&N Filters and modified airboxes, AC Delco RapidFires, Taylor SpiroPro 8mm wires, Energy Suspension polyurethane bushings for front and rear LCAs and sway bars, KYB struts and shocks, BFG g-Force Z-rated tires, MAC STB, JET low temp stat, CarSound Hi-flow Cat, DynoMax 3" Mandrel-bent pipes, Flowmaster muffler, 3" chrome tailpipes, T-tops, and White exterior with red leather interior.

2001 Sunfire GT
Bone stock 2.4L, 5-speed, K&N cone filter, interior detailing, 200W Monsoon Sound System (8 speakers), Silver Metallic exterior with grey interior.
3rd Place Stock Class at annual 2001 JCO Bash

Web: http://www.angelfire.com/on3/whitelightening