85F-body

what does ported plenum mean and do i need larger runners for it or what

irocz

It means that the area behind the tb has been opened up to remove the cast-in material that blocks the flow and also matching the plenum to runner holes. You don't have to have bigger runners to do it. Look directly into the TB w/ the blades held open and you will see the restriction.



------------------
87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 161,000 miles, !cat, 9" K&N

Ski89Z28

Take a look at this site it has pictures which I think is alwats better than words, no offense irocz. http://www.tribal-treasures.com/cars...-port/port.htm

Good Luck!

------------------
89 IROC 350 Auto
Custom DUAL Exhaust
Edelbrock Performer 6085 Aluminum Heads
ZZ9 Cam
TPIS Level 5 Chip
14.01 @ 97.0mph with 2.77's gears and a bad ignition control module!
And Free mods.

ws6transam

Hmm... I just shipped out a ported plenum today.

Porting the plenum is the first step towards improving the TPI. By itself, I'm not sure it makes a huge difference. It certainly makes NO sense to install a larger throttle body until the plenum is ported, nor does it make sense to install aftermarket runners or intake base without a ported plenum. The page referenced in the prev. post has some nice pictures on the improvements that can be made to the plenum. The above page shows how to remove a portion of the inner webs of the intake, which are simply figments of the casting process.

I've been porting plenums for about six months now, and everyone has emailed me with good feedback. No one has given me quantitative data, however, that shows that this performance improvement is worth "x" horsepower by itself. I suspect that the TPI is pretty much balanced right around the 200 to 245 HP level. I further suspect that to make signicifant improvements requires not only a ported plenum, but improvements to the runners, intake, and possibly the throttle body, mass airflow sensor, and associated ducting.

However, we all know that you can't do everything all at once. If I was to choose a starting point, I'd start with the plenum, JET (or TPIS) Aerofoil, modified MAF, and free home-made cold-air conversion as found on Andris Skulte's website http://www.skulte.com. These can all be accomplished for a total of less than $200.



------------------
Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Turbine Technologies 2500 stall converter, underdrive pulleys, Crane Hi-6 & more.
1.05g skidpad verified.
New best E/T! 14.039 at 100.82 MPH in 41 degree air at Stanton, Michigan.

85F-body

what can you do to the M A F besides take off the screens and throttle bodys cost an a$$ load like 500 dollars do you know anywhere i can find a cheaper one and also do 89 camaros have M A F's or M A P's ???

ws6transam

You can modify your MAF by removing the cooling fins from the inside. You have to be careful, but they can be milled out for better airflow.

As for the throttle body, I can get your 48mm throttle body bored out to 52mm for $225 plus shipping. If you want an aftermarket throttle body, I think I've seen some BBK throttle bodies sell for $340. Check out Carparts.com for their prices.

By the way, the 1989-1992 app is a speed density system and doesn't use a MAF so there's no need to worry about the MAF modification!

GregWestphal

iTrader: (1)

Actually, only the '90-92 F-bodies have MAP sensors (are speed density systems). The '89 still had the MAF sensor but not the cold start injector.

------------------
Greg Westphal
'87 IROC 305TPI/A4

ws6transam

Thanks, Greg, I stand corrected!