[RideWithDanger]

Originally Posted by wang970305

Im confused... the IM opening is choked back down to 87mm, how come the 95mm TB would work better than the stock 87mm tb

Because even at less open throttle, you still have more air coming through than you otherwise would, also allows for overall less restriction at WOT. It improves throttle response as well.

Personally I had my LT2 intake ported to help better match the 95mm TB, but even without that, a 95mm is still shown to have some improvement in power and throttle response over the stock 87. Its not huge, but better than nothing. Obviously porting the opening of the LT2 intake to open up the 87mm restriction is the best move when pairing it with a 95mm TB to optimize gains.

[7speed]

Originally Posted by RideWithDanger

Because even at less open throttle, you still have more air coming through than you otherwise would, also allows for overall less restriction at WOT. It improves throttle response as well.

Personally I had my LT2 intake ported to help better match the 95mm TB, but even without that, a 95mm is still shown to have some improvement in power and throttle response over the stock 87. Its not huge, but better than nothing. Obviously porting the opening of the LT2 intake to open up the 87mm restriction is the best move when pairing it with a 95mm TB to optimize gains.

Idk I previously had msd with ported 87 on my 17 then went to unported 95 and didn't see any difference at 1/4 mile.

So much in fact that when I got my 21, I just went with ported 87 with LT2. Granted 17 was stick and 21 is auto but best et is .6 better and 1/4 is 1 mph faster on my 21. (same mods but do have ati balancer on 21).

[RideWithDanger]

Originally Posted by 7speed

Idk I previously had msd with ported 87 on my 17 then went to unported 95 and didn't see any difference at 1/4 mile.

So much in fact that when I got my 21, I just went with ported 87 with LT2. Granted 17 was stick and 21 is auto but best et is .6 better and 1/4 is 1 mph faster on my 21. (same mods but do have ati balancer on 21).

You are comparing a ported 87 to a stock 95, so yeah there will be even less of a difference. I'm comparing a stock 87 to a stock 95. Im surprised the difference is only that much with the A10 + ATI honestly.

[wang970305]

Originally Posted by RideWithDanger

Because even at less open throttle, you still have more air coming through than you otherwise would, also allows for overall less restriction at WOT. It improves throttle response as well.

Personally I had my LT2 intake ported to help better match the 95mm TB, but even without that, a 95mm is still shown to have some improvement in power and throttle response over the stock 87. Its not huge, but better than nothing. Obviously porting the opening of the LT2 intake to open up the 87mm restriction is the best move when pairing it with a 95mm TB to optimize gains.

So it would still have some improvement by upgrading to LT5 from LT1 TB for unported LT2 IM, port the IM opening to 95mm would be the best way tho, right?

[RideWithDanger]

Originally Posted by wang970305

So it would still have some improvement by upgrading to LT5 from LT1 TB for unported LT2 IM, port the IM opening to 95mm would be the best way tho, right?

Correct, but you will need a tune. From what I have seen, its not a huge benefit without porting the snout on a dyno but people have said they definitely notice a better throttle response. You can always port the snout later too, and just do an update on your tune. I would suggest doing both at the same time for cost effectiveness though.

[Ventmaster]

+1 more for the unported 95mm TB and unported improved (LT2) IM. Back before there was a LT2, Matt@Tick performance posted the dyno's on an otherwise stock Gen6 LT1 engine. They had a stock car and bolted an MSD IM with a 95mm TB. It was impressive- see thread here: https://www.camaro6.com/forums/showt...&highlight=msd
Long story/short is it worked just fine on my car (no tune). The car felt stronger and continued to run quite well. It would seem a reasonable expectation that the 95 combined with the new and improved (unported) LT2 IM would have similar results.

[wang970305]

Originally Posted by Ventmaster

+1 more for the unported 95mm TB and unported improved (LT2) IM. Back before there was a LT2, Matt@Tick performance posted the dyno's on an otherwise stock Gen6 LT1 engine. They had a stock car and bolted an MSD IM with a 95mm TB. It was impressive- see thread here: https://www.camaro6.com/forums/showt...&highlight=msd
Long story/short is it worked just fine on my car (no tune). The car felt stronger and continued to run quite well. It would seem a reasonable expectation that the 95 combined with the new and improved (unported) LT2 IM would have similar results.

but the unported LT2 IM opening is only 87mm, has a 95m TB and taper back down to 87mm, doesn't make that much sense to me to be honest ....

[Joshinator99]

Originally Posted by wang970305

but the unported LT2 IM opening is only 87mm, has a 95m TB and taper back down to 87mm, doesn't make that much sense to me to be honest ....

Just because you have a 95mm throttle body doesn’t mean it flows the same as a 95mm opening in the intake. The throttle blade and shaft eat up a good bit of real estate, reducing how much air actually gets through the throttle body. Plus, you can simply open up intake opening to boot.

[wang970305]

Originally Posted by Joshinator99

Just because you have a 95mm throttle body doesn’t mean it flows the same as a 95mm opening in the intake. The throttle blade and shaft eat up a good bit of real estate, reducing how much air actually gets through the throttle body. Plus, you can simply open up intake opening to boot.

okay.. i think I see now.. I don't feel confidence to port the IM opening myself and not a fan of the RTV seal..I think ima just stick with 87mm opening

[EliteLT1]

Originally Posted by wang970305

okay.. i think I see now.. I don't feel confidence to port the IM opening myself and not a fan of the RTV seal..I think ima just stick with 87mm opening

Joshinator explained it well for WOT. The other point I was trying to make in an earlier post is, if we take half throttle for example. The 95mm will let more air flow in at half throttle than the 87mm

The area of a circle is pi*r^2 (gives us the opening of throttle body, ignoring the blade for simplicity)

95mm TB area: 7088mm^2 --> Half throttle = 3544mm^2
87mm TB area: 5944mm^2 --> Half throttle = 2972mm^2

At half throttle, if we're assuming half the area of the circle to be open, the 95mm TB has about 20% more of an opening. The same concept would apply for 1/4 throttle, 3/4 throttle, etc. Which would explain why you get a throttle response benefit during everyday driving

I'm also worried about porting the LT2 on my own so I did the same thing as you, left the IM unported and got the 95mm TB. And maybe pay to have someone port it in the future

[s346k]

i can contribute some info to this debate. anecdotal results but this is what happened.

full exhaust
stock lt2 manifold
stock tb

vs

full exhaust
stock msd
stock lt5 tb (ict billet adapter)

m6 car so i feel that is within the tolerance of driving & weather conditions, so its hard to say which one was realistically better. i measured 60-130 from hpt logs as this was before i had a dragy. 6 pulls with lt2 and 3 with msd. difference of averages was <.2 seconds. at that point the car was going 9.6-9.7. the msd was indeed faster but not by much. possible lt5 tb adapter issue.

if i had it to do over again i would have done a stock unported lt2 manifold and used a stock tb. having a larger tb than intake manifold is asking for tuning issues and a waste of time imho. achieve the same results with a pedal commander and never turn a wrench.

also. if using an lt5 tb, i suggest ovaling the mounting holes to avoid using any adapters. i was not happy with the ict billet adapter and ultimately took it off. the car kept showing low map kpa and i believe the adapter was contributing.

to answer your question: leave the tb unported. i saw .5 hp gain on the dyno from a ported tb on my bolt on engine.

[w123luke]

What would happen without a tune? When I bought my car I noticed when I opened the hood the manifold looked different but the dealership tried to tell me it was just missing it's engine cover... Well I've learned a lot about this stuff since I bought the car and I now know I have a LT5 TB with the LT2 manifold and I believe its ported as well. I took it to a tuner awhile back for various reasons and he told me it was running on a stock tune. At the time I didn't know about these mods so I didn't inform him of them. So the previous owner and possibly I have been running this without a tune at all for it.

[p47dman]

When you are talking about a port job on LT2 IM, are you also mating the ports to the heads? Or just the TB?

[SSShark]

I know this thread is a little old, but I have a question. From what I'm reading here, the way to go seems to be unported LT2 with only the snout ported to 95mm to mate up with an unported LT5. I've been reading every related thread while I wait for my intake and TB to be delivered. This is the combo that I think I will go with, but just looking for some encouragement.