aziroc

well when i was searching the net for T.B.'s i ran across BBK 58mm's for $300... is there anythign "different" about these T.B>'s as to y they are $200 less then Holley, Edelbrock, TPIS ect..

IROC-Z_85

I too am VERY interested in information about these.

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1985 IROC-Z, nuff said :P

MikeH

iTrader: (10)

I think the Holley is around 380.00 in Jegs. The Holley is billet were the BBK is cast Aluminum. The Edelbrock is the same as the BBK. TPIS is way over priced on everything.

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

LeeH

iTrader: (2)

My SLP 58mm was a repackaged BBK. Nice product.

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http://www.havemann.com/lee/firebird.html
1989 Firebird Formula, WS6 Package
ZZ4 Crate engine, Accel 24 pound injectors, Accel Superram intake, Accel Large tube runners
SLP 58 mm throttlebody, Edelbrock TES headers, SLP 3" SS exhaust, Random Tech 3" hi flow cat
700R4 trans w/ vette 2/4 shift servo, worked valve body, kevlar band, 2200 rpm stall converter
Borg Warner 9 bolt rear (full poly mounts) Hotchiss panhard rod, Lakewood LCA's, Spohn subframe connectors,
custom chip, Walbro hi-flow fuel pump, Accell HEI billet distributor.

breathment

58MM thats pretty big, u actualy thinking about getting it? If so wut mods u got etc.

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88' GTA 350 MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass

Kyle F

BBK 58mm Worked great on my TPI car. Only mods, SLP TPI Cam, INtake porting, 355, Headers, No Cat, Flomasters, and all the usual stuff like MSD and AFPR, and Bla Bla Bla. Really made a difference on my car, only thing was I had to fab a little on the Throttle cable, but after a Sping and a screw it worked perfectly. Woke my car up.
I know a lot of people are going to say you will lose low end power, but if you have a MAF car there is no explnation for this because your car does not run based on Vacume, but Mass. So if you have a Speed Density this will hurt you to go to big, if you have a MAF, well I am telling you from experience that it will work.

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!

b92z28

my local auto-zone has the holley 52mm for $230.

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92 z28 170,000 miles 14.20 on goodyear eagles before exhaust only mods k&n and slp 13/4 headers and dual 2 1/2 exhaust
87 trans am 12.20 on motor too many mods to list

b92z28

my local auto-zone has the holley 52mm for $230.

Matt87GTA

Lets think about this kids...

48mm(stock) TB flows 640cfm (I think.... - someone will correct me if I'm wrong)

52mm TB flows 790cfm

58mm TB flows 1000cfm.

How many 1000 cfm carbs do you see out there??

It is true that a SD car will be much more affected by this mod in a negative manner than a MAF car because of the design of the system. But 1000cfm?? Is that necessary?? I, along with most of the guys I know, don't think so. I have a 52mm on the way.

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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23*, LT4 Hot Cam, Ported plenum and intake, SLP Siam Runners, Edelbrock TES, gutted Cat, Flowmaster, K+N cone, AFPR, TB bypass, AirFoil, !AIR, !A/C, !EVAP, ARAP, 2300 stall, Hotchkis STB.

rondubbs

this topic has come up over and over again...
the stock 48mm is capable of flowing plenty.
just get an airfoil and port your plenum. save the money for another mod, i wish i did.

aziroc

well the reason i need a 58mm T.B. is because it *along with a new intake and runners...all ported and polished* are going on a 500 hp 406. now tell me a stock T.B. can flow enough air.

raven350

aziroc:

Some poeple will tell you that it will... Due to a certain article taht used one on a big block and the numbers that it got...

But what they failed to do was test a bigger throttle body on the motor and post those numbers.

I also have a 58mm BBK throttle body and I like it.

GlennS87

I use the BBK piece and it has worked well for me. I have heard about spotty quality control, so their couls be some inconsistency.

As far as why you wouldn't want to use a 58mm on a stock or mildly modified 350 has nothing to do with absolute flow. It has evrything to do with velocity. When the velocity of the intake charge is reduced, you can lose torque. The TPI due to its design actually creates its own small ramming effect due to the "tuned" nature of the runners. That's what gives TPI such good low and midrange torque.

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Neptune, NJ
White '87 Vette - 383 Superram ported and matched to TPIS big mouth intake, Eagle cast crank, 6"eagle forged rods, srp/je forged pistons, LPE 219 cam, ported heads(2"x1.56" ferrea valves), Comp cams pro-magnum 1.6 rr's, double springs, titanium retainers,Hypertech power coil and cap, 4 bolt block, TPIS headers, auto(trans kit,shift kit),Pro Torque 2600 stall converter, k&N filter, 3.07 rear diff., Silver ZR-1 wheels 17x9 and 17X11

Matt87GTA

Well, the higher the 'absolute flow', the lower the velocity of the air that flows through it at lower rpms. So how does 'absolute flow' have nothing to do with what type of engine it should go on?

As far as the 'absolute flow'; people aren't thinking about how much overkill they are strapping to their engine with a 58mm. Sure it will flow better on the top end than the stock one, but I am willing to bet that all but the largest cubic inch engines will see the same results with a 52mm. I do think that the 48mm is a little small for modded engines.

This issue is easier to understand if you compare the flow of the TB to what size carbs people run on comperably built engines. Granted a FI engine is, in most cases, more efficient and will take more airflow. So a 52mm (790 cfm) has pretty much everybody covered.

my $.02

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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23*, LT4 Hot Cam, Ported plenum and intake, SLP Siam Runners, Edelbrock TES, gutted Cat, Flowmaster, K+N cone, AFPR, TB bypass, AirFoil, !AIR, !A/C, !EVAP, ARAP, 2300 stall, Hotchkis STB.

91-ZZ4-Z28

I run a Accel/LPE billet 58mm and it is great and flows mutch smoother that the BBK.

RBMZ28

think about it 1000 cfm 58 mm.whay's missing is the fact that this is dry flow numbers!!!
comparable to a carb. it would equate out to an 875cfm( some one correct me if i am wrong).that being said ,a stout 350 or 400
would need and love this t.b.!!

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87 IROC WITH 409(.040 OVER400) MINIRAM,NOS(125HP)TRICK FLOW PORTED HEADS,C.C.CAM,FLOWTEK HEADERS,CUSTOM PROM,MODIFIED 700R TRANS,2400 B&M CONVERTER,3.73POSI REAREND.
LOOKING FOR THE 11 SEC. ZONE.

MikeH

iTrader: (10)

Are carbs rated at wet flow numbers?

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

Kyle F

Yes carbs are rated in wetflow, but comparing a carb to a FI sytem is just rediculous. A wet flow system need velocity crossing the throttle bores to pull the gas out of the venturies. Thats how a carb works. This has nothing to do with ourt dry flow design. The Tuned runners will create their own velocity. The Velocity crossing the throttle blades has nothing todo with the runner velocity unless it is not allowing enough air to enter the plenum. THe plenum acts as an air storage area. If it didnt the back two runners would not get as much airflow as the front two. So the velocity crossingf the blades has nothing to do with the velocity of the air entering the heads. Its a basic equation of fluids. Area1*Velocity1=Area2*Velocity2 so since the plenum just stores the air up anmyways you want to pump it full of air and use the smallest runner possible that will flow the amount of air you need to feen your engine. Though GM did something cool though when they designed the TPI system. They based the Airflow capabilities on the second Harmonic. TO those of you who didn't study waves in Physics its like when a wave in a pool hit the side and comes back, the second time it hits is the second harmonic(well it can actually get a lo more complicated than that, but thats it in a nut shell. This is the most powerfull point in a wave. SO actually it has a ramming effect and the TB has noaffect on this at all.

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!

Matt87GTA

At WOT the plenum is no longer a 'storage area'. That is where the TB comes into play and that is the only point that it comes into play,as far as size issues go.

I am not directly comparing a dry FI system to a wet carb system. Of course they are not the same. But you can somewhat get an idea of what you need by looking at them.


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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23*, LT4 Hot Cam, Ported plenum and intake, SLP Siam Runners, BBK 52mm TB, Edelbrock TES, gutted Cat, Flowmaster, CAI w/K+N cone, AFPR, TB bypass, AirFoil, !AIR, !A/C, !EVAP, ARAP, 2300 stall, Alum. Driveshaft, Hotchkis STB.

Coming Soon!!: Fourth gen 3.42:1 rear, Spohn LCAs and Panhard, '99 Camaro seats.

Matt87GTA

Nope.

Kyle F

Nope with a large enough ThrottleBody it can still remain one Thus not choking your engine do to your Throttle body size.

Besides Like I said the TB has nothing to do with the velocity in the runners. Well atleast not in this type of design.

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!

RBMZ28

I understand what you are saying about velocity,and i say again it would be a restrictor on a stout 350 or strong 400.Wher velocity would be great at low rpms,it would'nt pass enough air to support either of these motors at high rpms(6300 or better).
Not that I'm a 302 fan butI was wondering why Ford motorsport t.b. is rated considerably higher(70ty something if i remember correctly.By the way I think it complements a 406 miniram very well.

Matt87GTA

[quote]<font face="Verdana, Arial" size="2">Originally posted by Kyle F:

Quote:

Nope with a large enough ThrottleBody it can still remain one Thus not choking your engine do to your Throttle body size.

Exactly. So when you increase the size of the TB to the point where it no longer is a restriction for the rest of the intake system (I think the 790cfm flow of the 52mm more than accomplishes this) you are done. You no longer need to make the TB any larger. If you do, it will be overkill for the rest of the engine. And the plenum is not a 'storage area' at WOT because the incoming air is not under a large vacuum at that point since the TB plates are fully opened. The plenum is no more a storage area for the incoming air at WOT than the rest of the air intake system and, for that matter, the rest of the atmosphere. So the only thing, at that point, you have to rely on for intake air flow is the physical shape and maximum flow (size) of the intake componants themselves (ie TB, runners, intake port of head, etc...). That is when the actual size of the TB is relevant.

I don't know, maybe I am thinking about this all wrong , but I think the TB has more of an effect on the engine's intake system than you are suggesting.

Laterzzzzzzzz

MikeH

iTrader: (10)

I dunno.. Lingenfelter says I need a 58mm for my SuperRam so thats what I got.

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

breathment

All you guys with summit mags out there. look up the throttle bodies in there, it says 52mm is for stock or mildly modded engines, and 58mm is for really high flowing engines. I personaly would go with a 52mm unless i had a supercharger.

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88' GTA 350 MODS---&gt; air foil, K&N, Shift Kit, 180* therm, TB bypass

Scott 88 GTA

RBMZ28 - the reason that the Ford TB's are 70mm is because they only have one butterfly. The TB's on our cars come stock with two 48mm butterflies, which is almost as much area as one 70mm.

Mono 70mm = 3849 mm^2
Mono 80mm = 5027 mm^2

Twin 48mm = 3619 mm^2
Twin 52mm = 4247 mm^2
Twin 58mm = 5284 mm^2

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Black 88 GTA L98
261 RWHP, 345 RWTQ
13.406 @ 103.72 MPH
ZZ4 bottom end, Edelbrock 6085 heads, LT4 HOT cam, GMPP 1.6 RR's, ported stock TPI, SLP 1 3/4" headers, no cat, Dynomax cat-back, Stock PROM
E.T.F.A Member #11

Greenshamrock77

Just to give you a feel for how much a 48mm TB can support, the 502/502 ramjet BB uses a stock 48mm L-98 TB. It makes 510 HP.

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82' Z-28. 327" w/ flat tops. 216/228/112LS. Pocket ported 041 heads 1.94/1.50 SS valves. World Class T-5 from a 91'. Best run? Runs with 2001 vette to 150mph! Soon to be converted over to TPI w/ supercharger.

Kyle F

I used to be an Engineer For Liebert Corporation, which does HIgh Performance Air Conditioning ( I always thought that was funny when somone said that LOL) and we used plenums on are systems for a reason. It helped balace airflow. Ofcourse we were flowing the ooposite direction in a way, but the airflow characteristics remain the same.


I wish you guys would stop it with the 502, Sorry we ar dealing with 305's and 350's and I am sure we could pull 1hp per cubic inch on ours with a Stock TB to. I am waiting for someone to buy one of those and alsp a 58mm TB on it and all of the sudden have like 550hp.

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!

IROCZZ3

My 2 cents on this subject a couple of weeks ago...
https://www.thirdgen.org/messgboard/...ML/003349.html

Some of y'all need to stop reading magazines so much and preaching theories and do some real track testing, where it really counts!

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1989 IROC-Z, ZZ3 shortblock with some bolt-ons.
13.20 @ 108.69, 2.2 60'

[This message has been edited by IROCZZ3 (edited July 24, 2001).]

Kyle F

Yeppers, my 58MM on my 355TPI made me quicker. It took me from a 14.1 to a 13.9. It was what I was missing from my 13 sec recipe on a 2.77 gear N/A. With a Full stereo and in strret Trim

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!

1bad91Z

iTrader: (1)

Paging Kyle F ...... Maybe you can help me with this!! By the way the reason I went with a 58mm TB is so I wouldnt have to buy it twice when I install the Procharged 355!! Here it goes..I just installed a new Holley 58mm TB. The car idles like CRAP when it's cold, have to pedel it to keep it running until it gets warm! I've adjusted the idle screw out so it would stay running, but then the idle stayed to high (1600 - 1700rpms)after it was warm. So with the car running and now warm, I adjusted the idle down to 1200rpm. If I keep the car running at this setting, it idles fine until I turn it off and it cools down. With the idle set at 1200, it idles like crap when I start it again when the car is cool! I live in Houston, so the weather is between 75 - 90 all the time, so It's not cold weather causing it to do this. Also, I'm having a problem with the Transmission detent cable. The **** on the throttle linkage on the Holley is a hair bigger than the stock TB, so the detent cable cant swivel like it's supposed to!!! ANY HELP will be appreciated!!! By the way when the car is at operating temp, it screems now!!!

Kyle F

I posted a reply in your other post sorry I didn't get to it sooner.

Though I just had another thought to. When I installed mine I bumped up the Fuel pressure 1 psi according to my guage with no vacume. And set the base timing back one degree because I started to get some knock around 4700rpm, right before the sift. I had to fiddle around for a few days before I got it dialed in with the 58MM TB

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!