speed_demon24

That's assuming the engine is always sucking in a steady amount of air and that the 600cfm is with 0 pressure loss.

camzaro28

^^^Final answer?
So end thread?

onebadponcho

Let me quote myself since this seems to have been overlooked:
That was just going from 48mm to 52mm on a STOCK 350 LT1 with a STOCK cam and a STOCK exhaust. You're talking about having a 383 with I'm assuming heads/cam/headers/exhaust/CAI, etc, and you think you'd only gain 5hp? Also, if you're patient, you shouldn't be spending $350 on a larger TB. You should be able to find one pretty easily for about the cost of a CAI kit, and I don't see many people around here saying those are a waste of $$$.

96LT1TX

You will come to a day where 350$ for 10 HP will be well worth the money, like I am at now. Shorty headers and stock TB are what keep me out of the 11s (and bad launching). I am about to break down, but not yet. I want to break 11s w/ stock TB, fuel pump, shorty headers just for fun first.

Bersaglieri

Ask Madwolf how his bigger TB worked for him. This isnt a new topic. I'd go bigger when you get a bigger cam and ported heads, or more.

-Dustin-

klrz28

An engine is an air pump, more air in = more air out producing more horsepower..

B-Rad420

You have a totally valid point but I personally would rather see results from an individual that has nothing to gain from the results. That book was made to be sold and you have to have interesting info to sell something. TPIS also probally donated the tb for advertising so even if it made no rwhp difference they are gonna put that it did anyways. I am not saying a that a bigger throttle body is not needed, I have no idea. I would just like to see some other results. Hopefully someone here has installed heads and cam on an engine with a stock TB and then bought a new one and installed it later. I really would like to keep mine stock if I can because I like the stock engine look and I plan to always stay with stock valve covers, heads and intake with porting to both (sleeper). I like doing the most possible with as little money invested as possible and $350 is a good chunk of change. I would rather spend $350 on gas driving my car around and enjoying it than gain 10-20 hp if thats all that can be had on a N/A motor.

dangalla

that does not make any sense, how are results from a dyno test on a throttle body gonna help him sell a book.

and you can port the stock throttle body to keep that look you want, and it will cost you alot less. leaving your throttle body stock will cost you power, if you want to know how much injuneer has already broken that down very nicely for you

Injuneer

I went back thorugh my archives, and found some dyno test data that I printed out 9 years ago. It was a series of dyno tests run by an indivdual named Markus Strobl, who had access to a dyno at Dynotech in Dallas, beginning in the summer of 1996. The results were on a website that no longer exists.... www.cyberramp.net/~mstrobl/96dynotest.htm. This appeared to be an individual who just wanted to test some of the popular mods of the day.... not a magazine, not a dealer, not a manufacturer. The documentation of the testing is fairly thorough.

The tests were run on a 96 Z28 with "Borla catback, Moroso airbox, Hypertech programmer plus, Homeported heads and 1.6:1 roller rockers".

Remove MAF screen: +1.1 HP, -0.4 lb-ft
Replace 48mm TB with stock TB bored to 52mm: +2.5 HP, +3.2 lb-ft
Add airfoil to 52mm TB: +1.1 HP, -1.9 lb-ft
MSD-6A: +3.5 HP, +4.7 lb-ft
Hypertech Power Program: +3.0 HP; +0.9 lb-ft
Cool down engine by spraying nitrous on intake: +7.0 HP, +11.1 lb-ft

dangalla

did you see the dyno sheets for that fred

what was his rwhp? and also i am assuming that is peak hp and tq, how was the average increase?

B-Rad420

My bad, It makes sense to me. I didnt mean it in that exact sense of just that book and test. If someone donates/advertises with a magazine/book/whatever of course they are going to make results look like what the company is advertising. Otherwise why would they keep advertising if all the magazine did was say that it did nothing or state a very minimal gain. Think about GMHTP and the companies that give them LT1 parts to test....mostly gay stuff. Book's sometimes do the same thing thats why I find it hard to beleive info from something/someone that is making a profit.

I also know that Injuneer has broken it down to me, 10rwhp. Thats why I stated 10-20hp gain....
Brad

Javier97Z28

All technical details aside... here's my cold hard facts.

I consistently gained 1 MPH at the trap after installing my 58mm TB. That's all I care about.

Car's that need 'em, gain from it.. those that don't... well they wasted money.

96capricemgr

I will completely agree on not trusting sponsored information and feel TPIS is one of the worst big vendors out there, they charge and arm and a leg for alomost no improvem,ent on a lot of their crap.

That said take a vacuum reading after it is together and try and get vacuum low see what it takes to get that. My money is you will endup needing a TB unless the heads are weak. If going 52mm a rebored stocker is THE way to go asves some of the hassles and issues guys have had with aftermarket units so you get your sleeper look.

Heads I would argue that for the overwhelming majority of applications ported stockers are the best choice not just the "sleeper" choice. If you thought using stock castings was just a "budget sleeper" idea as opposed to actually being a very good choice then you have not done enough research yet.

On the vacuum thing, the old rule with carburators was shoot for 1.5" or less vacuum at WOT with a street car, any more and the carb was a restriction. Using that rule let us know what you find.

B-Rad420

No I wanted to use them because I am going the AI 200cc route. Might go the 185cc route if I dont need the 200's with a smaller cam and 355 cubes. I also know because you have some of the most realistic posts on the forum and you def push ported stockers.

97SS0594

my AS&M 54 whistles when the car runs is that normal