TPI Intake Plenum inlet air restricting bump- kill it?
 

My TPI-style FIRST fuel injection intake has this annoying air flow inhibiting bump right at the bottom of both the throttle body outlet and the plenum inlet.

I talked to Ken and on the actual TPI intakes it was for some sort of EGR inlet. I will NOT be implementing EGR so I'm thinking I should probably grind the thing out into oblivion and remove the air restriction.

Thoughts?

I understand all I'd be doing is moving the bump back and making it a more gradual ramp, but with the restriction right at the throttle body outlet it seems like the worst possible place for it. If I move it back 1-2 inches by grinding it down the bump doesn't happen until the midst of the plenum where the air speed has already slowed down and there's a lot more room.

https://cimg0.ibsrv.net/gimg/www.cor...8f84098ea1.jpg

To be honest, I already removed half of the bump, but my dremel sandpaper flapper wheel died in the middle so while I wait for new ones to show up, I figured I'd pump the brakes for a second...


Adam

Yup, the bump is for the old EGR crap.
My builder ground it down and filled it when he ported my FIRST.
:thumbs:
Attachment 48254201

Leave it be it wont restrict anything

OMG that's beautiful! And insanely time-consuming / expensive-looking.

What did he fill it with? -I don't want to break through to any hollow cavities so it's good to know that if I make it perfectly flat that that will happen. I'm probably going to just clean it up from where it is now when my new flapper wheels get here, match the gasket to what I have and then grind the throttle body side to match and call it good.



What's the state of your build these days, Ezobens? You get the CAI figured out?


Adam

I'm honestly scared to not listen to you at this point, but can you humor me and provide your thinking behind this statement?


Adam

Why does the entrance to your first couple runners look partially siamesed while the later ones don't look like they are at all?



Adam

Thanks!
Yeah, my builder said it was the first and last one of these he was porting just due to the labor involved. :ack:

The EGR tube will need to be filled if you grind it down.
I believe he used block fill- The stuff they use to fill-up water jackets.
I suspect you could use JB Weld or something similar as well.

I'm neck deep in the CAI issue right now.
The biggest challenge is that the TPI sits so far forward and with the MAF on top of it really gives almost no room to play with.
I decided to go with the 82' core support for more air flow and ended up getting a new radiator while I was at it (talk about project creep!). :willy:

The front most and rear most pair of runners were siamesed the first inch or two in an attempt to get the flow among the runners as close to each other as possible. Seems the front pair and rear pair have the most restrictions.
Elm

welcome to tpi porting...lol the time spent is rediculous not many guys want to fool with them. At least you sprung for a good one instead of fooling with a factory piece- you can make good power with a FIRST

Other than the packaging challenges I have putting it on the C3, I have high hopes this will give me the big-block like low end torque I've been missing with the SBC.
:thumbs:

Somewhat similar, but I port matched my 82 crossfire manifold with my trusty dremel. Took one whole day per port. Ears got tired of the high pitch of the tool. Anyway, to the point, I took off the egr runner and filled the hole with JB weld and then smoothed the whole thing over. Wish I had pictures, but I lost them all when Crossfire Injection Forum went ka-put. Pictures stored there. Good ole Ken73 deleted all my pictures over a dispute. But he is long gone and I am still here.

It will youll love it ezobens.

I'm done with grinding mine down then; I do NOT want to deal with filling the EGR passage. I'm just going to clean it up so it looks a bit more pretty and gasket match it, then match the throttle body bump to the gasket and call it good.. (I've already removed 1/2 to 2/3s of the bump so I'll take a 2/3rds reduction in bump-related air restriction for 1/4 the work of filling the EGR passage and grinding everything down again.)



Are you going with a stock GM TPI ECU?
I don't even have the option for MAF as I went with Holley EFI and they're MAP-only.

I am getting a new radiator as well, but now I'm curious about the 82 core support? -you're talking about the bracket that goes under the radiator, right? -Does the 82 core support lower the radiator to give more clearance to run CAI up and over or something?


Adam

Ezobens do you have any other pictures of your FIRST or a build thread somewhere?

Your plenum is so "max effort" that I want to see the rest of your build.


Adam

The 82 core support does not change the position of the radiator vs previous year C3s. The only real difference is that there is a 'dip' at the top of the support to allow more air over the top for the Crossfire Injection CAI.

Yes, I am using the GM 1220411 PCM for my install, which is an LS PCM not a TPI PCM from the 80's-90's. I'm tuning it to work with the TPI (sequential injection, 1 coil configuration).
Elm

I don't really have any uploaded anywhere currently as I have pics on several computers.
The challenge I seem to be having with this site is that I can upload like 1 pic and then the upload tool doesn't seem to work again unless I reboot and try again. Very annoying and I can't figure out why I'm having the issue since my pics are within posted size limits.. :banghead:

Here's the weird thing: I talked to Ken @ FIRST and he said that the intake's EGR passage is solid cast now; it's not drilled out, nor cast with an EGR passage way... I'm confused why yours had to be filled.

Did you ask to have the EGR passageway put in yours?
-I know he keeps slowly changing stuff with the FIRST overtime, but now I'm confused why yours broke through into an EGR passageway that supposedly doesn't exist on mine...



Adam

Not that this matters....but has anyone every tried this.

I have and it works.


I often times get customers that want to get that last little bit out of their engine for whatever the reason.

I will say that doing an intake for an engine with a carburetor is something I would not do if the car is street driven.

DUB

Nope. The price is truly obscene for a full TPI intake. (ESPECIALLY when you consider that this is just silly putty (literally same substance) with some abrasives mixed in.) -Yes, they have to build a fixture for each intake, but you can't tell me that each of these companies don't already have a fixture for these intakes.


I also had the FIRST intake and my combo modeled in EA Pro by a guy on ThirdGen and increasing the inside diameter on the FIRST intake runners loses me more torque than it gains me in HP in the RPM and displacement that I'm using.

Maybe if I had one of those big cubic inch FIRST builds it would be different but with my 350 cubic inches now and 383 in the future and my desire RPM peak of 6,300, it's a move backwards after emptying my wallet.


Adam

The cost to have a full TPI or FIRST intake extrude honed back in 2008 was $900... My entire FIRST intake only cost me $1,050...

I can't remember how much material one pass of extrude honing removed but I think it was 1/10th of an inch... for $900?!?


:crazy2::crazy2::crazy2: