nikh23

hey guys, quick question that i know can be resolved with the search but as we all know its down for now.

My question is, is it worth it to port the TPI intake manifold, along with the runners and plenum, or should i not even waste my time and energy and save up for an aftermarket manifold. I thought that it would be a waste of time and I would see minimal gains but others have told me that i'd see a decent improvement. by the way i'm on a budget since i'm a college student. so the ultimate question would be woudl porting the intake help for the time being on a 305 tpi?

Guest

Its only a 305, just port what you have.

1MeanZ

iTrader: (9)

i assume we are referring to porting the intake base. that is tough to do. all i was really able to do to mine was port match it. i have no tools that can reach in the middle of the intake and open the ports. there are flow numbers published in a either a gm high tech or chevy high performance magazine. the stock runners flow the same as a stock base. so doin anything other than port matching is a waste of time. if you port the base so that it flows more, it will only be restricted by the stock runners. they both flow the same, so in order to get any kind of actual power gain you need to upgrade runners and base together. then you will be limited by stock heads, but they can be porte with good results on a 305. i would say port the plenum, and then port match the rest of what u got and if you still feel you need more flow, port your stock heads and install 1.94 intake valves, and install aftermarket runners and base

D Stroy H8

I would just get the edelbrock base/runners package. It's only 650.00 in Summit these days. That way, in the future when you actually do need more flow you can even further port out the edelbrock piece to make some excellent flow for a 305.

nikh23

ok well i think i'm going to just go ahead and port the sucker for now, and then later go for aftermarket stuff. so now the other question that comes to mind is should i spring for the edelbrock package in the future, or buy a modified lt1 intake off john for 400. which would produce more power? and don't include the 350 swap for now, thats way down the line

D Stroy H8

LT1 intake will be to much for that little 305. I'm telling you, you're going to wish you already had Edelbrocks stuff when you go to get it after porting the stocker. Just trying to save you some money/time.

nikh23

yea i would love the edelbrock stuff but 650 bucks at the moment is just too much for me, i have nothing to do over my spring break so i guess ill just give it a whirl see what i can gain from it

LYV18F

the converted intake might be $400, but you'll need a whole bunch of other little parts. if you look at the sticky thread at the top of this page (i'm pretty sure it's one of those, if not, i think it's in tech/ general engine) there's a whole list of stuff you need. i'm not saying anything bad about the lt1, it just seems like everybody thinks you just get it and bolt it on.

i guess it's that way with everything.

come up with an estimate of how much it will cost, and double it. come up with an estimate of how long it will take, and triple that...

nikh23

yea i know the lt1 intake consists of the modded intake from john for $400, remote t-stat around $65, and custom fit fuel lines for around $60. according to john's site that consists of most everything thats needed

D Stroy H8

Well see you didn;t imply you were gonna port it yourself. Cause then you're spending time not money, and thats different.

nikh23

yea i would def try to port it myself, not siamese but just enlarge the holes a little bit and gasket match them

shawn87gta

iTrader: (1)

I bought the Standard Abrasives porting kit, which came with a long bit for the sanding rolls. I was able to reach the center of the intake runner bores with this in a die grinder. I also bought a drill extension and turned it down a little to fit the die grinder, not the best approach but it will work.

If you have time & patience and no money to buy expensive goodies, you can probably see some gains by doing this - just don't expect huge gains. The key when porting like this is to match & smooth everything so there is minimal disruption of the air as it flows through the system. Here's how I think you could maximize your investment:

1. Remove the intake and pull a pattern off the intake ports in the heads. I used some mylar sheets to do this, whatever, it just needs to be rigid enough not to stretch or deform. Transfer this pattern to the intake and port each opening to match its mate. Only go as far as achieving a blend from the rectangular intake port shape to the round runner shape for now. You may find the intake ports in the heads are smaller than the manifold ports, if so leave this end alone.
2. Look into each of the runner tube openings, there should be steps where the tubes are welded to the flanges. Remove these steps, this is about all you'll get here. Measure this diameter to use as a guide for match porting the runner side of the intake.
3. On the intake where the runners bolt on, you should see where the casting shifts inward from the opening at the sealing surface. Open this up to match the diameter of the runner - going any bigger is a waste of time and costly sanding rolls. Port this diameter as consistently as possible to the middle of the intake runner.
4. Go back to the head side of the intake and port to the center to achieve a consistent diameter thru the length of the tube. Blend back into the rect intake port area.
5. In the front of the plenum where the throttle body mounts are the EGR walls. If you have never seen how high these are you will be shocked. Grind these walls down to match the plenum openings.
6. Make sure the runner gaskets do not intrude into your newly formed openings or you have just dicked yourself. Cut them if you have to.

You will probably get a little improvement out of this porting, but for the amount of work you may be disappointed. With the intake removed you are not too far away from pulling off a cam swap - if time & funds allow, this WILL make a difference if you choose the right cam, and probably more of an improvement than the porting. As a matter of fact I would not remove the intake until I could afford to replace the cam - but that's me. While it's tore apart there are some maintenance things that will help too. Send the injectors to Rich at Cruzin Performance to have them cleaned and a set matched. Buy a throttle body gasket set and completely disassemble & clean all the passages. DO NOT hose down the entire IAC with carb cleaner, carefully clean the tip. Clean everything immaculately before reassembling. Cam swap, port matching, a complete tune up and K&N filter and you would likely be smiling when you hit the road again.

nikh23

I've actually already done the plenum and runners up to the this point. I had bought an extra set of these two things and polished and opened them up a little bit while up here at school on my downtime. I figured before i swap these in if i could get a hold of an extra intake base and open that up a little bit too i might be gaining a few more hp here and there. I would love to do the cam swap but at the time thats just out of the question especially with the mileage i have no the engine i woudl have to do a lot of headwork as well. I was planning on having my injectors cleaned while they were off, as well as throwing on an AFPR in the process. Lastly my question is how do i go about rebuilding the TB, i've never actually done it and have heard very little about it, if you could provide some insight i'd greatly apprecciate it

shawn87gta

iTrader: (1)

Getting your parts ready in advance is the best approach in my opinion. Get it all together, buy your cam/lifters & other parts then do it all at once. I've been collecting parts for two years now....

You're not actually rebuilding the TB, you're just removing the top and bottom plates and cleaning air passages.

nikh23

sounds like a plan, and also where can i get the gaskets for the two TB plates? i can't seem to find them anywhere

shawn87gta

iTrader: (1)

The dealer should have them if your local auto parts stores don't.