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I was looking around and couldn't find a DIY on porting a LT1 throttle body...so thought I'd take a could pics of how I ported mine. I didn't bother taking pictures of the throttle body removal, if you can you have a problem with that part this isn't for you lol. I have never ported a throttle body before but am pretty handy and have been working on cars for 20 years. I was bored last weekend and thought I'd give it a shot. Took about 4 hours from the uninstall until I reinstalled the throttle body on my car. Overall I'm pretty pleased with the results. Definitely improved throttle response. If you're not comfortable with power-tools and engine parts I would just recommend just buying a ported throttle body from one of the forum vendors. Hope this helps someone else.
Throttle body before Tools used - Dremel tool, grinding stones, 80 grit sanding wheels, 200, 400, 600 grit wet sand paper, liquid wrench, polishing compound, and rags. Soak the grinding stones in liquid wrench to prevent them from getting clogged. Using the grinding stones I carefully and slowly removed the lip. Keep them somewhat wet with liquid wrench to stop the aluminum from clogging up the stone. You can see the "no go" area in the center where the throttle blade closes. DON"T TOUCH THIS! 80 grit sanding wheel used to roughly smooth out the throttle body. Done with the sanding wheel. After fine sanding. Note that there are some areas where I ground a little deep leaving the scoring marks. They look a lot worse in the picture than in person. A little polish. And all back together. Filed down the back of the bolts too.
I started with a Katech PTB for the machined down throttle shaft. I than ported it out more & called it a Tech-Mo+. It performed as expected, more for less throttle input off idle compared to the stocker (87mm). However it is now on the shelf. I'm trying that new (un-ported) ZR1 95mm TB. I hope to have some track results soon.
Last edited by C7/Z06 Man; Sep 24, 2018 at 06:49 PM.
383vett - Looks good! I removed the throttle plate though since I was worried about damaging it. Your hand is steadier than mine!
C7/Z06 Man - I was originally going to go with the Katech PTB for the same reason. Down the road I still might.
Avanti - It wasn't really a money issue, I just wanted to see if I could since I've never done porting work before. And if I messed it up would have just bought the Katech
The LT5 TB can be ordered from any GM dealership. https://www.gmperformancemotor.com/parts/12669871.html It will bolt up to the stock IM but the opening needs to be ported so the throttle plate can open completely under full throttle. The other option is a LT5 to LT1 TB adapter plate which reduces from 95mm to 87mm. Kind of negates the point of a larger TB if you're reducing back down to 87mm though. One of the guys on the Camaro forums is running the ported IM with LT5 TB, but has a tune. So not sure if it would throw a code or not.
The LT5 TB can be ordered from any GM dealership. https://www.gmperformancemotor.com/parts/12669871.htmlIt will bolt up to the stock IM but the opening needs to be ported so the throttle plate can open completely under full throttle. The other option is a LT5 to LT1 TB adapter plate which reduces from 95mm to 87mm. Kind of negates the point of a larger TB if you're reducing back down to 87mm though. One of the guys on the Camaro forums is running the ported IM with LT5 TB, but has a tune. So not sure if it would throw a code or not.
LT5 TB will not bolt up to the stock IM due to a 'slightly' different bolt pattern which the adapter plate takes care of and the plate is approx. the same I.D. as the 95mm TB. Also the LT4 supercharger's opening is approx. 87mm and due to the spacer the LT5's throttle plate will not hit (I know). I'm not really sure if the LT5 throttle plate would hit without a spacer or porting because I did not check that out.
With adapter plate it's a bolt-on deal.
If you did match port the opening in the supercharger to the ZR1 throttle body it would most likely wipe out the groove where the round green sealing gasket goes in and leave very little sealing surface.
I think the Camaro guy drilled the LT5's TB four mounting holes larger until it would bolt up; by passing the need for an adapter plate. That would than most likely require some porting.
Last edited by C7/Z06 Man; Sep 26, 2018 at 01:37 PM.
LT5 TB will not bolt up to the stock IM due to a 'slightly' different bolt pattern which the adapter plate takes care of and the plate is approx. the same I.D. as the 95mm TB. Also the LT4 supercharger's opening is approx. 87mm and due to the spacer the LT5's throttle plate will not hit (I know). I'm not really sure if the LT5 throttle plate would hit without a spacer or porting because I did not check that out.
With adapter plate it's a bolt-on deal.
If you did match port the opening in the supercharger to the ZR1 throttle body it would most likely wipe out the groove where the round green sealing gasket goes in and leave very little sealing surface.
I think the Camaro guy drilled the LT5's TB four mounting holes larger until it would bolt up; by passing the need for an adapter plate. That would than most likely require some porting.
C7/Z06 Man - I see you edited your original much more condescending post from yesterday lol. As I stated the LT5 throttle body can be be bolted to the LT1 manifold with some porting. Watch the video - https://www.youtube.com/watch?v=htgy...ature=youtu.be.
Good job and I’m glad it worked out for you. In my past life I used to port just about everything on my cars, exhaust, tb’s, manifolds, turbos...you name it. Pretty easy with the right tools. Don’t use them much now as they sit in a nice box in my garage...lol. I do use my die grinder pretty often as I’m a professional ice carver and it’s invaluable! Been using the same Mikita one since the 80’s
C7/Z06 Man - I see you edited your original much more condescending post from yesterday lol. As I stated the LT5 throttle body can be be bolted to the LT1 manifold with some porting. Watch the video - https://www.youtube.com/watch?v=htgy0Gj8Wag&feature=youtu.be.
If you check your video closer/again: You will notice that the guy drills (not port) the 4 mounting holes in the LT5 throttle body larger to get the throttle body to bolt up to the LT1 intake manifold like I said.
Also you can see the green rubber sealing ring and it's groove when he holds the LT5 up to the LT1 manifold inlet which would need 'porting' to match the larger hole in the 95mm TB and that would not leave much of a sealing surface if you check the video closely. Have a good day.
Last edited by C7/Z06 Man; Sep 27, 2018 at 12:31 AM.
Could you port the intake while still installed in the car?
I would not. You may get grindings, etc. into the engine (that stuff flies everywhere) which may do the same thing to the piston rings, cylinder walls, etc. I have a supercharger which requires more work to remove but if you have an LT1 intake manifold it looks pretty easy in the video to remove/replace.
Last edited by C7/Z06 Man; Sep 27, 2018 at 11:53 AM.
I posted a thread a while ago regarding porting the throttle body and in particular removing the lip.
I am speaking from first hand knowledge. I first ported my stock throttle body. If you remove the lip, the air increases significantly between idle and 20% throttle opening. The manifold vacuum decreases and the ECU interpretation this as increased engine load so it pulls 15 degree of timing to compensate. Then at about 2800 rpm, it restores the timing. And when that happens, the power jumps up and the car surges. I confirmed the pattern by logging timing with HP Tuners. Very irritating.
I scrapped my stock ported throttle body and bought a Katech ported throttle body. It also had the lip shaved. Same thing happened. So I contacted Katech and explained the problem and they replaced it with a new one that didn’t completely shave the lip. Problem solved.
So, you must enjoy the process a lot more than I ever did. 
My DIY ported throttle body
