It's great so far. The car pulls quite a bit harder from 4000RPM up, is more willing to rev, and just feels better, especially from 50MPH on up. I wish I had track times or something else concrete to offer, but that will all come in due time, hopefully within the next few weeks. I'm hoping for mid 14s and a 94-95ish trap speed. BTW I'm not even realizing the full potential of this because my timing is set around 4 degrees advanced... 2 degrees below the stock setting. The distributor cap is stuck against the EGR solenoid and I can't advance it any farther.. I'll figure out something though.

As for what I did, I used a Dremel with the Flex-shaft and a carbide cutting bit, and I ported the plenum, runner openings (removed casting flash from the openings), then I moved on to the runners and removed the small ridges at the openings of each runner tube, and finally I spent most of my time on the intake manifold itself, removing material from the intake at the runner/manifold interface to give a better transition from the runners to the intake, and to give the air a straighter shot at the head openings. I also worked on the head side of the intake manifold a little, enlarging the openings to match the gaskets.

total cost: $28 for the flexshaft, $8 for grinding bits (the cylindrical and the conical shaped ones), carb cleaner to clean out the metal shavings, $3.

time spent: roughly 20 hours of work

this is definately worth the time... if you have a TPI car DO IT

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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday

 

I'm using my air compressor and a 33,000rpm grinder with SNAP-ON metal cutting bits. I siamesed all four ports in the intake in less than 3 hours so far. I'm thinking about using my dremel for the flash right before the heads but I havnt decided yet. Good ob though man!

 

MrJ- Sounds good. When I get my L98 done this summer(ZZ4cam,headers,ported heads,etc) I plan on gasket matching all the TPI and porting the plenum. Only thing is that I'll be doing motor,porting, and all mods all at one time so I'll probably just see one big change. Its good to know that it all adds up though in steps like you've done. Hell, if I prolong my L98 much longer, I may just pull the TPI off my LB9 and port it. Then I'd really know if it helped me. Well, good luck at the track! Later

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'91 GTA:
www.fbody.com/members/91WS6GTA

 

I'm still working on the programming, but I can say I've hit the 6200RPM fuel shut-off twice now with no problem. Unfortuneately the first time was when I was teaching a LS1 T/A to respect thirdgens. (Went home with tail between legs after redlining )

Setup includes:
Ported plenum
Siamesed SLP runners
Ported base
LT4 Hot cam
And more...

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Bob '89 Ram Air Formula 350
And until that time when death won't wait, let each man rage against his fate. (O'neill)
My car's homepage
Rider's Ride

 

Rob, you crack me up!

You are right though, many folks that are doing the siamesing are talking about noteable SOPT differences. However, no one seems to be posting quantitative data! Does anyone have any concrete befre/after data that they can share?

 

That's an extremely hard question to ask because most of the people who do porting and stuff like that also modify something else in the process. Why take the manifold and everthing else off if not to throw in a cam, or headers, or 1.6 rr's.

I figure on any p&p job gains are less on a stock car and increase more significatly the more modifications you do. It's cheap and if not done haphazardly will always net some increase.

The only hard rules are not to lower the intake floor more than to match the gasket. Raise the ceiling as much as possible (Even laying aluminum weld on the intake runners to raise it more than the casting allows is great), if in doubt it's always better to make the intake port smaller than the head port and the exhaust port on the head smaller than the pipe it's flowing into.

Porting heads is a whole different ballgame...

 

Dan I'm hoping to run this fri and for the first time since installing your ported system everything is good to go.Hoping to run better than a 14.78 w/stock cam & heads.
Fri's run willbe baseline for retro-fit project.
Bill

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86 IROC mods:T.E.S.,Flowmaster muffler
T.P.I.S. airfoil,Dan Burk ported intake system,,March
pulleys,Accel 8.8wires,ign.mod,Crane PS-91 coil,Crane HI-6S ign.box
RAM AIR induction,gutted MAF,
B&M shift kit,3.73 rear gears,Accel afpr,Hypertech stage 2 chip,Random Tech.cat.,Lakewood lower control arms,Lakewood adj.panhard rod,mac subframe connectors,PST polygraphite bushings
"The more I learn about women,the more
time & money I spend on my IROC"