JustAGoat

iTrader: (6)

I have some noob questions and some opinion questions to ask of everyone...

The car is a 99 trans am m6 car. The engine doesn't have the air emissions system installed, but all except the MS4 cam it is completely stock. It does have 1 3/4 long tube headers to a 3 inch ory to connected to a mufferless SLP cat back (catless). Also it has a SLP lid.

The plan is to put a FTP 98 mm lid, a abaco 98mm mass air flow sensor and fast intake and throttle body and go get a nice dyno tune.

So question one would be would a 92 mm fast be the best intake for the setup or do you think i would lose anything going to the 102 mm?? (i have heard witha stock ls1 displacement the 102 mm isn't the best choice)

Question 2 is it possible to put on heads while the the motor is still in the car??

Question 3 are the stock injectors fine?? (I think they are)

Question 4 what throttle body do you guys suggest?

Question 5 Does anybody on here run a abaco MAF i'm trying to get rid of the big cam bucking and i heard the maf would help out and ony other opinions on the maf??

I was hoping after putting this maf and fast intake that the car would be around 420 rwhp where i would be fine with leaving for right now to build the rest of the car up over the next few years and then come back and do a nice motor build...

Any opinions and suggestions would help
thanx in advance
Jason

dudeiwin86

iTrader: (1)

yes u can do heads without pulling the motor.
yes, (IMO) 102 is way overkill on a stock cube LS1
look at a 90 or 92 setup (IMO)

SS4Luck

iTrader: (10)

im about 200% sure my dyno was reading high, but MS4 cam only w/ an ls6 intake, pacesetters, TSP TDs under the axle with 4.10s i made 428/407 to the wheels

you could save the money over a fast and go with a used LS6 off of a forum member and save major cash. for the rest of the intake system just match the MM of the lid to MM of the MAF to MM of intake throttle body.

SweetS10V8

iTrader: (4)

Keep guessing...

You too...Keep guessing.....

Why is it that no one gets that the throttle body opening has ZERO to do with "being too big". As if it were a cam that is too big?????? Its not like that!

Its not a cam, There is no "too big" for throttle bodies when talking about power, you could put a 300mm TB on it and it wouldn't change the power nor be "too big". The runners in the intake are what determine "too big, too small, etc" The create flow an velocity on their own for each port, exactly like individual throttle bodies do. THE RUNNERS are what make the power, not the throttle body.

The throttle body simply has to be large enough to feed enough air to supply all 8 runners.

The best option would be to get a 102mm intake and bolt on a 92mm TB. Because at your power level, your 8 cylinders arent going to be asking for more air than a 92mm can provide. If you go with a 102mm TB go with the FAST, it has a built in convelude(sp) that helps drivability with such a large throttle body. My brother is installing one on his car right now.

I run a 102mm intake with a 90mm DBW throttle body.



EDIT: I found this for eveyone, this is FAST even says about the 102;

dudeiwin86

iTrader: (1)

a 102 intake with a 90/92 tb... ok, that may work
still overkill and not worth the extra money IMO

but a 102 tb on a cam only car is going to lower intake velocity.
no thanks.

SweetS10V8

iTrader: (4)

did you not read what I just told you?? The runners create velocity not the throttle body. The throttle body only has to get air in the plenum . How Di you think individual throttle bodies work

dudeiwin86

iTrader: (1)

yes i read what you said, but unless youre a mechanical engineer with facts behind it... your word of mouth doesn't make it "correct".

the entire intake system all the way back to the air filter is a "duct system".

youre creating turbulent areas in the intake runners by changing velocity that quickly. its better to have high velocity from the start of the system. less turbulence. less static pressure. more flow with less work, where work = wasted power.

bww3588

iTrader: (49)

im with sweets10...you dont know what your talking about...

incase you didnt know....

air doesnt get sucked into the intake, it gets pushed in by the atmosphereic pressure 14.7 to a lower pressure in the intake. the intake is only going to hold as much air as it will take, that includes the amount of air being used by the cylinders (including reverberation).

the TB opening and velocity of the air coming in has nothing to do with power or anything of the sort. the only way velocity and turbulence play into power is with forced induction. but even then, once you pressureize the plenum, its over.

bww3588

iTrader: (49)

and BTW, mechanical engineering has nothing to do with air movement within an engine. that would be fluid dynamics....

bww3588

iTrader: (49)

oh, and one more thing...

if it was overkill, FAST would go out of business because they would have lost 80 percent of their LS market when they discontinued the 78/90/92 intakes and TB's. a 102/102 is perfectly fine for a STOCK engine. yes stock engine. that removes the having to change once you mod. its an intake and TB setup that is good for stock engines all the way to insane.

dudeiwin86

iTrader: (1)

did i not say that it would work with a 92mm tb on the 102 mani? its still overkill.

fluid dynamics is part of getting a mechanical engineering degree. sorry for the confussion...

if the intake manifold is just a "box" to "hold" the air..
and the heads make all of the velocity...

why port the intake manifolds ?
why does a dual plane make more low end torque than a single plane?
why does a single plane make more high end hp than a dual plane?

having a 90mm or 102mm tb doesnt change the maximum ammount of air a 346cu engine can use.
assuming 100% VE you can use 700cfm at most. good luck getting 100% VE.
92mm is plenty for that CFM.

SweetS10V8

iTrader: (4)

Could be, but thats why you can use a 92mm TB. Its preference. A 102 TB wont hurt anything but drivability possibly(That's why FAST built in the convolute in the 102mm). This is a dry manifold, It only flows air. It could have the ability to flow 5 million CFM, but the runner are only going to "ask" for so much depending on your heads/cam/etc. Its not a carb where having it be "too big" is bad.
OK, reading is fundamental....try it. The RUNNERS in the intake determine velocity, flow, too big, too small, too long, too short, just right, etc. Anyone can build a box to sit on an engine. FAST just has better runners than everyone else. Because they have different RUNNERS in a single vs dual plane. Seeing a pattern?


I google image searched this for you....The green pieces are the runners....

dudeiwin86

iTrader: (1)

i agree on all counts.

i guess ive been raised on a different school of thought.

when you oversize, you have low velocity and low pressure, so you create a "balloon" effect for your runners to draw from in the plenum.
my problem with this is that you go from a low pressure to high pressure situation when entering the runners which creates turbulence.

ive always preferred sizing for max velocity with no restriction so that there is no change (or as little as possible) in static pressure in the system, and thus no turbulence created.

and if turbulence didnt matter, they wouldnt waste time porting the flashing off the inside of intake manifolds and minor "touch up" jobs on head castings.

maybe im too **** about airflow (since i work with it everyday). and it really just doesnt have that much of an effect. but its just principal.

ill have to spend a little more time playing with some numbers.

Jim85IROC

iTrader: (6)

I'm just an electrical engineer, so you can toss what I'm going to tell you into the trash too, but please allow me to try and explain why the throttle body size doesn't matter:

All the throttle body does is provide air to the plenum. The plenum "stores" air for the individual intake runners to pull from. In electrical engineer terms, the plenum is like a storage capacitor. The plenum volume is large enough that it should eliminate any velocity/flow issues, other than those within the runners/intake ports themselves. As long as it's feeding enough air to the plenum for it to supply the runners, then the throttle body has done it's job.

I don't have them in front of me, but I have seen dyno tests on various cars (mostly TPI cars) with various throttle bodies. Horsepower levels are unchanged on any motor whose air requirements are below what the throttle body is capable of flowing. There is a lot of FACT out there that supports this.

Generally there's no drawback to a bigger throttle body either... just don't expect a benefit. Often they make a car feel faster at part throttle because you're letting more air in for any given TPS value. On that note, I would imagine that if you go too stupid-big, that it could cause issues without a tune because the airflow will be way beyond what the computer expects for a specific TPS voltage, but that's just a theory.

bww3588

iTrader: (49)

your not moving from a low pressure to a high pressure....your moving from a low pressure (plenum) to an even lower pressure (runners and cylinder) simple physics would tell you, the lower the pressure in the plenum, the higher the velocity in the runners would be. a higher pressure always wants to move to a lower pressure.

bww3588

iTrader: (49)

thats why the more plenum volume you can get the better.

dudeiwin86

iTrader: (1)

i should have said "static pressure". mah bad.

and JimIroc... you only reinforce what i originally said.
its OVERKILL. there are no gains to be had. why pay for it?

--

that said, i admit some of my previous argument was faulty.
i did a little more research on the internals of the fast manifold, and they shape it different than i anticipated
(yes, im an LSx newb and am basing too many of my asinine comments on my experience on another platform)

for looking so similar to the late model hemi intake manifold, the FAST is lightyears ahead in the thought behind the guts of it.

i can see what you would just want to blow it up like a balloon and let the runners do the work.

in the hemi stuff... we have a "tube" inside of the intake manifold before you get to any of the runners.
oversizing throttle bodies would kill our velocity thru the manifold and it wouldnt stay full of air.

thanks for the schooling.
p.s.
102mm throttle body is still overkill

fatmat80

SweetS10V8

iTrader: (4)

I like threads where good information is passed on. I see some stupid/crazy threads, and you feel like you trying to talk to a brick wall...


Thats why its cool the 90/92mm TBs still bolt up!