: Ported vs. Larger TB?



BlownV
04-26-13, 11:11 AM
Have a bone stock V-sedan that is begging for me to mod her so I have come up with my initial list but I do have one question. I will be doing intake, 2.5" upper, 160 tstat, heat exchanger and ported snout to start. Most likely going to add cutouts to that list just for the optional sound when I want it. I am not sure whether to just port the stock TB to match the snout or if I should go larger on the TB? WeaponX has their 102mm TB and 102mm intake that seem like a good setup...but is this worth it over just porting the stock one and running an airraid? Any issues associated with the larger TB setup that anyone has encountered? Anyone done both and have dyno numbers? Thanks for the insight guys!!!

HUGN*RDS
04-27-13, 11:12 PM
One thing to consider is the fact the throttle body is only as large as its smallest diameter so if you are porting the stock one, the butterfly valve is already x millimeters so porting the opening in front and behind that valve will be effectively reduced because the diameter of the butterfly is the bottleneck. I would check out the LS7, I've been eyeing that one. May not be big enough so YMMV.
Later

V locity
04-28-13, 12:31 PM
If I had it to do over again, I'd leave blower & TB untouched. The quickest V right now, on 93 gasoline only (no NOS or meth), runs 10.2s & he has not touched the blower or TB.

Da V-Man
04-28-13, 01:57 PM
One thing to consider is the fact the throttle body is only as large as its smallest diameter so if you are porting the stock one, the butterfly valve is already x millimeters so porting the opening in front and behind that valve will be effectively reduced because the diameter of the butterfly is the bottleneck.
Not exactly. The TB acts as a venturi. Porting both sides of the TB causes the airflow to speed up as it passes through the narrower butterfly section, so it doesn't really act as a restriction. It's a similar phenomenon to the shaping of exhaust nozzles in rockets.

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If I had it to do over again, I'd leave blower & TB untouched. The quickest V right now, on 93 gasoline only (no NOS or meth), runs 10.2s & he has not touched the blower or TB.
And if he had touched the blower & TB, would he now be in the 9's?

BlownV
04-29-13, 06:58 PM
Correct on the venturi effect. If you port the TB on both sides, and port the snout to match the TB so that all the transitions are smooth then I would expect there to be some gains...the question is, how much? I am already going to port the snout while the shop is pressing on the smaller pulley, so it is just a matter of whether the expected HP gain from porting the TB is worth the cost or not? 2-3hp...not worth it, 10-12hp...worth it.

Da V-Man
04-29-13, 07:46 PM
If you don't have other mods that increase airflow significantly, I wouldn't expect too much HP gain. However, the faster airflow makes for better cylinder filling at lower engine speeds, which translates into improved throttle response.

BlownV
04-29-13, 11:25 PM
Intake, 2.5 upper, headers, cutouts, ported snout.

CADZLA RETURNS
05-03-13, 11:10 AM
If I had it to do over again, I'd leave blower & TB untouched. The quickest V right now, on 93 gasoline only (no NOS or meth), runs 10.2s & he has not touched the blower or TB.

+1 It's very easy to get sucked into all the hype and end up buying unnecessary parts, services, etc. Bigger is not necessarily better. I got caught up with the Whipple hype, spent $7200. Does is make more power than stock? Yes, if it doesn't break. But it's not worth $7k+. Period. There were ton of guys saying how great Stainless works is, so I spent $2400 on the full system, only to regret it. The alignment is terrible, the mufflers are 2.5, not 3. The headers are a work of art but other than that I would not recommend them (maybe just the headers or cat back, but not both). I bought a $450 4.5 intake tube that connected to a NW102. 102mm is 4 inches, so a 4.5 inch tube is useless. 4.5 going into 4 inches is pointless. Fortunately, the company (which is a stand up, respectable company) allowed me to return it for a full refund. The bottom line is don't overdo it, don't over think it, keep it simple.