Last night i took apart my upper and lower intake. Took about 2 hours maybe. damn lower intake needs a nice porting job it's resticked like a champ. I didn't relize that where it mates with the heads its very restricked looking. So i'm gonna clean all my intake parts then start porting the lower intake as much as possible then smooth out the little groves on my runners then port my pleuim. So nothing to crazy just mooding up what gm should have never let slide of the line. if anyone has tip please let me know. i'll be getting gaskets and porting/ sanding tools at sears soon. haha can't wait till she's up and runing. Oh one more thing i think i'll be getting an air foil and a fuel pressure regulator ajustable. Anyone think thats a good idea?
Thanks

 

forget the airfoil.

And btw, dont clean anything before you port it. once you start porting you will "clean" the areas youve ported and the grime will be like a guide coat. when you are done porting then clean stuff.

 

I used "sanding drums" to great effect when I was doing my porting and matching. Good luck with your project.

 

Yeah thanks for the tips guys, 1989GTATransAm you did A porting job right? Just wondering what kind of results you got? Did you feel a nicer pull up in the higher rpms? I think since i'm in a corvette that low end torque is not needed becasue i spin to much (because it's light) so hopefully doing this my top end will pull and hopefully get my shift kit to do it's job corretty and get me sideways like it should. My parts should get here pretty soon. Oh i all pulled my valve covers off and barely barley barley tighten my rockers i mean like a notch. Just to get a little slack out of the 98,000 mile motor. Thats a good call to right?? Anyway thanks y'all hope to here something.

 

Well I wouldnt rip my valve covers off my L98 and start adjusting rocker arms till I have the valve lash specs.

tho it shouldnt be to detrimental to the engine, I wouldnt have done it.

 

With my modified TPI and porting my max horsepower is now at 5000 rpm according to the dyno.

 

Cool thanks again

 

I did my plenum and a little base work with a "roto-zip" bit on a dremel.
Cuts aluminum like butter (almost that fast anyway)
Then went back over with sanding drums.
I was happy for my first time doing it.
Opening up the first of the 4 center holes on my base took me over an hour with drums, and stones(bad to use on alum).
After the "Bit" was put on, the other 3 took 15 minutes.
Good luck.

 

So did you get good results? i'm keeping it all stock and porting away.

 

JP86SS,
Not to get off topic but what roto-zip bit did you use? Do they have one specificly for metal?

 

STD one that came with the Dremel.
1/8" X 4" long aprox, might have even been 3/16 diameter.
I love it!

Now back to your regularly scheduled discussion

I still have the stock exhaust so my new heads and porting did not yeild the results I was hoping for.
Stealth Ram in my future...

 

JP86SS,
results where not all that huh? Did you do it to a 305 or a 350?

Kinda off topic, but does a L98 350 in a 88 vette use a differnt cam then say a 88 Iroc L98 350. I know heads are the same but i think the only differance is a cam. Just wondering what results i might have after porting.
thanks

 

It was a 350 but I didn't go hog wild on it.
I removed the main restrictions near the IAC ports and cleaned up the walls behind the TB. Did "some" matching of the ports on the intake to heads.
the runners were untouched because it didn't appear to me that i could do much to really make them better.
it was my first time and was more interested in polishing the unit than porting. (yea, I know "all show, no go)
I really expected a little more going from the 1.94 intakes to the 2.02's on the Sportsman II's but I think the exhaust is really killing me for the top end. the heads I took off were the GM 183's (don't remember but think that is correct)
Don't get me wrong, the thing pulls like hell out of the hole but still gets the feeling at 4800 that there should be more. Above that it does seem to flatten out. Still left me wanting more so I do wish I put more time into it when it was apart.
He's a bit of what I did. I smoothed out the wall on the right side a bit more after the picture was taken. You can see what needed to be removed.

 

At least the show part worked out
Good luck with your project !

 

Wow very nice work, what did you do to get it coated like that, did you sand it or just clean it up then paint it? and with what type of paint. Spary paint? or brush it on, how many coats. Will it chip off later and look ungly? I think as far porting i'm going to make sure i invest a great amount of time in that area. cutting away unneed crap. It's gonna be a fun project. The bad part is my car is down for a couple weeks and its pimping summer time everyone has there rides rolling around town.

Thanks

 

All polished, no coating except some high temp clear on the fuel rails. I polished them, then used some red "chrome" type paint I got form Autozone. It really looks good over polished surfaces. I didn't polish the TB and just painted it and it came out darker than the rest. Probly should have silver base coated it to bring out the color. 2 coats of the spray paint works out well and I think its called "ColorChrome".
I used a belt type sander to get everything smoothed out on the plenum surfaces, then used a DA with 400 grit. I recommend doing it that way to keep the surface flat. I originally just smoothed it and polished but it looked ripply and didn't give the result I wanted. Once it was "ground" flat by the belt (I think it was 120 grit) the DA and polish work came out real nice.
From then it was polished on my buffing wheel.
The runners were done completly with a 4" buffing wheel on a drill. (My arms hurt after the 5 hours of polishing)
The little "flap" wheel type sanding tools worked pretty good on the runners to get the "orange peel" look of the cating out of them. Lots of small spots that were difficult I used a file to get into.
Like I said, The porting turned out to be a secondary matter so I really just wanted the easy major restrictions removed in hopes of a little better flow.

BTW, glad I spent a couple of nights making the engine block and front end orange(insert sarcastic tone). It's completly covered up and can't be seen even if you try But I know its there.

 

Damn man it look very nice. I think i might use a wire brush to clean up my parts then just buy the color crome you used. Will it chip away from the heat? I think i'll do the same to my vavle covers too

 

They will look like this with a silver base coat.
Haven't had any heat problems yet and has run for about a month or so. Its a little "chippy" if you scratch, but not if rubbed. hope that helps.

 

Wow love this porting thing, just taking forever. This job takes maybe 2.5 hour per port on the base. I'm seeing that i'm doing a pretty nice job cutting away the restricktions amost making it prefect. I honestly didn't think i was that good at it. Although the first thing i ported out was my pleuim the left side wall right behind the throttle plate opening. I f'ed up and got carried away and cut a very small hole into the side of the pleuim. Very very small size size of the @ symble if not smaller. I was pissed on how stuiped i was not pay attention but nothing a little JB weld wouldn't fix. I spread a nice think layor on the inner and outter areas around the whole maybe an inch around the hole. After that i made sure to continue to cut and check cut and check. Using a burr on a wiz wheel makes the job like cutting through butter. I can run through different RPM s pretty flexable using air tools. You'll probably think i'm a jack a$$ for cutting through my pleuim you live you learn i guess. The only thing that keeps popping into my head is maybe i should buy a new pleuim just in case the vaccum from the motor sucks in the weak part where the hole is in the pleuim. I know you'll can't see the area i f'ed up but what do you guys think should buy a new pleuim or keep this one? The area that thin is not very wide it's only in an 1/4 of around and the hole in the center. I mean JB weld is the ****. Ummm

 

And or maybe scrap away the JB weld and use those aluinim radeator flux sticks. Not sure what will happen if i scrap the JB weld if it will make it bigger or not. Please help
thanks

 

I don't see why a nice goob of epoxy wouldn't do the trick.
It would hardly be noticable and can be shaped on the outside.
A goober on the inside to bond the two sides together when wet would never come out (hopefully)

 

Wow finally done with my base intake. It looks pretty nice much bigger to where it mates with the heads and remove the bumps where the intake meets with the runners. Next is my pleuim and runners then i'm done porting. Then its clean and making everything look nice. Can't wait till i try driving it. I wonder what kinda results i'll get? Most people say not much i guess.. Umm? I really need to take her to the trak after this. I'm hoping my vette at least runs 13.5 I think stock is 14.1 or something.

Here are all my mods when done, let me know what you think it might run in 1/4 miles

1.)Eprom( I've reprogrammed runs great with my last version i programmed i'll list those details later)

2.) 180 thermostat

3.)Ported runners, pleuim,base all gasket matched.

4.) throttle body foil

5.) Headers (1 5/8 factory) gutted center cat, no mufflers just pipes out the back,

6.) Stock 350 corvette motor aluiminn heads from factory

7.) all fuilds very very clean sntheic oils and fushed may times

8.)Fuel presurre regulator (ajustable)

9.) stock 24lb injectors

With all above on a 88 vette you'll think i might be runnng 13.5. I think i might runn 13.2 or 13 flat. Ummm? not really sure. I know what i've done it's **** but i no before all this it was running really good. Pulling by my buddys convertiable 2000 cobra too may times and smoking stock GTs all day long.

Later Mods

1.) stroker motor and all listed iteams above and mill the stock heads 10 or 15 thousands of and inch not more.


I live out in VA so theres only so much i can do to stay clean for edmissions. Other wize i'd be buy regals and drop LS1s in then all day long. hehehe one day once i'm outta this silly state.

So after all this is said and done i'm buying a blm cable and software then start to change fuel and timing curves for maxuim hp and tq within rpm vs load.

This site is kick a$$ even though i'm might need to be posting on a vette site. It's all the same Product. GM's is the $hit.

 

nice job! with that porting i think mid higher 13's is not out of the question... my 89 Iroc is doing 13.8's with 2800stall on 2.77 gears with only headers and catback exhaust. some suspension work as well. your vette should be 200 lbs lighter i think so it should be possibly 13.6s-13.7s. a good torque convertor should help out ALOT tho

and this site is very good for technical info on TPI and transmissions that can be applied to all cars using TPI and thirdgen parts like street rods, TPI vettes, and offroad trucks using TPI

 

Thanks Man, This is really turning out pretty nice. Once get all my parts painted and thrown on the car, I'll setup an new post with all my pictures. I'll show my ported areas long with the paint job on the parts. and final shots with them on the car too. It's been a long job and to many beers but the hardest parts are outta the way and form what i see i like the results. The d@mn lower base is no joke when porting. It takes a long time and lots of detailed work. I think my nebors will be very happy not hearing my die grindder grinned away. Silly nebors have had to listen to me cutting away at my intake for weeks and weeks.

 

No matter what, It always runs better when you do it yourself.
Attention to the details... Priceless

Now that mine is pretty good looking, I'm going to change to the HSR (Polishing now) so now my neighbors have to hear it some more too! Heck with 'em, It for a good cause.
Good Luck.

 

Yeah the ol nebors don't understand but they will once she's done. They said they'd like to check it out once it's done. I think it'll be running it this weekend hopefully. can't wait

 

It's alive runs pretty darn good too, The ECM is in need of a little reprogramming. i need a BLM logger soon too, program the best way. Also once i have my pictures devloped i'll post them.

Thanks for all the help everyone

 

Did you get a dyno of all those mods before you ported the TPI? If my ac problems ever get resolved, I am doing some TPI porting and I will supply dyno results. Just wondering. Keep us posted.

 

No sorry no before dynos. After dyno's i'll get soon hopefully. OMG though last night i burned a chip to kinda match up to my porting job. Good Lord bad @ss ride thats all i gotta say. it's faster thats for sure. i can feel a big differnce in preformance. bottom end it still pretty good too. the cyilinders have got to be filling up faster. I'd have to say from the feel it's gotta be very low 13's or higher 12's car. I'm very very pleased with my results. Every stop light i stopped at people where smiling at me, the sound is much meaner too. anyway I'll be posting so pictures and hopefully my dyno results. next mods hopefully next year is 383 short block TPIS cam and mill my factory heads 10 thousands and fully roller motor roller lifers, and rockers

 

I didn't read this whole thread but form the pictures I see people are not taking out the "taper" on the two throttle body inlet holes. The holes start out as 48mm and go down much smaller because of the taper. I grinded the taper off and smoothed it all out.

 

yeah i saw that tappered part i smoothed it out. thnaks

btw i've seen your ride around town everyonce in a while. Fairfax that is. nice ride