BBK 1537 THROTTLE BODY INFORMATION

[EOLIVER]

Hey fellow Vette owners, I'm considering the BBK 52 MM Throttle body (model 1537) for my 1989 Six Speed Conv, but I was wondering if anyone had purchased this model and whether it comes equipped with the necessary manual transmission hook up , or whether the linkage had be changed out from the original TB? It does not make sense to me, to have to transfer the connection point from the old TB onto a brand new one.

 

[LT4man]

I have the BBK 52mm Throttle Body on my 1996 LT4. Fit with no problems whatsoever.

They have a technical hotline 800 number. You could always give them a call.

Good Luck!

SAVE THE WAVE!

 

[EOLIVER]

Thanks for the quick response lt4man, is you car a six speed

 

[LT4man]

Yes, all LT4s from the factory are ZF 6 speed manual transmissions. All LT1s came with the 700R4 automatic transmission. The higher horsepower and torque rating of the LT4 was considered by GM engineers as too high for the automatic transmission.

SAVE THE WAVE!

 

[JEFNLSA]

I have the BBK 52mm on my LT4 as well. No problems here either...

 

[grumpyvette]

OK IVE JUST GOT TO ASK?
why would you buy a 52mm vs a 58MM throttle body????
now PLEASE don,t get me wrong,
the 52MM has a nice improvement in air flow over the stock throttle body, but in most cases that extra air flow is not used, especially on a mild engine or one with stock gearing and displacement, and the 58mm won,t in most cases increase the performance, and yes IM well aware from testing that the MAF sensors and the intake manifolds , and heads are the big restrictions, and that with out inproving those areas the stock throttle body works just fine.
BUT NEITHER WILL THE 58MM HURT a damn thing EITHER??
I tried BOTH on my 383 with BOTH the TPI and STEALTH RAM intakes, (I borrowed a friends 52mm to test, and I bought and installed a 58mm on my engine)and there was no real differance untill I was up in the 6000rpm range, and even then the differance was minor, but again WHY buy the smaller unit, that could potentially be a restriction with future mods done??
its NOT like a carb, you won,t get a big loss of throttle responce, in fact I could detect ZERO differance once it was correctly tunned) or for that matter experiance any down side to the larger unit provided of course your tunning skills are decent.
and before you guys get crazy, do some research!
I don,t remember ever seeing a dyno on anyone elses engine EITHER that showed a LOSS to the larger unit, just a few that showed no IMPROVEMENT in a particular application, and if your thinking of pointing out a lack of throttle responce thats been repeatedly shown to be due to tunning issues like low fuel pressure, too small of injectors,or the TPS voltage was off the mark, the IAC was not set correctly or the ignition timing curve was not ideal, or in a few cases the compression ratio was to low for the cam sellected, get the LCA or durration wrong for the application and AIR FLOW REVERSION in the runners CAN cause problems, like a bog when you transition from idle to W.O.T. almost instantly, but in no case IVE seen was the extra potential air flow a problem, especially once you realize that the plenum/ports carry only AIR, and the fuels injected in the last 4 inches of the runners

BTW
http://www.sallee-chevrolet.com/frame.html?/sales.html

RAM JET 502 - FACTORY FUEL-INJECTED BIG-BLOCK POWER
P/N 12499121 [Old P/N 12497323]
The recipe is simple; one part attitude, one part driving perfection, one part leading factory technology, and five hundred and two parts hungry rat motor. Ram Jet 502, you either have one, or you want one! When the idea of an all new big block fuel injection system first came up, we all thought it was a good one. When it was proposed that it be integrated with our 502 crate engine, we thought someone had clearly lost their mind. Who could possibly need the awesome, flat, broad torque curve only available with a long runner dry manifold? And who would want the neck-snapping throttle response of MEFI 4 controlled port fuel injectors? And what would be the need for aggressive tunnel ram styling? But then we remembered we’re not building 100 mile per gallon, 0 to 60 in a week, eco scooters. We’re in the hot rod business! So we called together engine management system experts from GM Powertrain, our own GMPP engineers, and fuel injected race engine builder and GMPP Pro Mod racer Harold Martin. After some great discussions, a little debate, a lot of late nights and 50 gallons of coffee we had an intake manifold design like no other. By leveraging leading fuel management technology, numerous production developed components, the industry standard MEFI 4 controller and the great Ram Jet name from the 50’s, the Ram Jet 502 is reality.
The new undisputed heavy weight champion, the Ram Jet 502, makes 502 horsepower at 5100 rpm and 565 ft.lbs. of torque at 3200 rpm. The instantly throttle responsive Ram Jet 502 drives like no other big block you’ve ever driven. With over 500 ft. lbs. of torque from 2,200 to 5200 rpm, the Ram Jet 502 is a tire shredding monster making more torque throughout its operating range. This is possible because Ram Jet has a larger plenum and runners than would ever be possible in a carbureted application. This means greater intake efficiency and greater torque without sacrificing driveability. The Ram Jet manifold is so efficient that we’re able to make all of this horsepower and torque with a production L98 throttle body assembly, you know, the one that Firebird and Camaro owners always replace when trying to make more power in their 350 engines. It’s all about airflow quality, velocity, and fuel and spark management. You’ll just have to drive one to appreciate it. If the one-second cold starts, no stalling, instant throttle response, and the solid pull from idle to red line don’t convince you that a Ram Jet 502 is for you, then maybe you would be more interested an a competitor’s futuristic dream of a 100 mile per gallon, 0 to 60 in a week, eco scooter or a good old fashion bicycle for those weekend events to impress all your friends at the local hot rod club or for those weekend cruses out on the highway to impress everyone else on the road.
The Ram Jet 502 is designed for ease of installation needing only 12V, ground, fuel feed and fuel return to run. Included are an instruction sheet, service manual and diagnostic tool for ease of installation and service. As with any GM Performance Parts Ram Jet engine, an in tank fuel pump is recommended to avoid possible vapor lock. See instruction sheet for fuel pump recommendations. Also included is complete throttle linkage that accepts your production throttle cable and transmission cable. Includes pre-programmed MEFI 4 ECM and wiring harness. This revised electronic and closed loop system gives a much smoother idle and better performance then the MEFI 3 ECM system it replaced.
The Ram Jet manifold stands eleven inches tall as measured from the front and rear “china wall” on the cylinder block. That’s just half an inch taller than a typical single plane high rise manifold, Holley carb and air cleaner combo.


RAM JET 502 TECHNICAL INFORMATION

 

[JEFNLSA]

Mine was on the car when I bought it.

 

[LT4man]

Simple reason to use the 52mm Throttle Body.

General Motors opened the air intakes in the LT4 intake manifold to 52mm. So, if you install the 52mm TB in the original manifold there is no need to match port the manifold to the TB.

If one was to use the 58mm TB, one should port the openings in the manifold. If one did not do that, you would be left with a major restriction in your air flow.

No wonder they call me lt4man!

SAVE THE WAVE!

 

[grumpyvette]

I suppose that manifold porting issue is a valid concern if your not willing to do the minor port work thats necessary,
but if your to the point where the throttle body is becoming a restriction to your power curve your well past the point where youve done far more extensive mods, than a minor porting of the opening behind the throttle body.
before the throttle body swap is worth the effort youll need new heads and an extensively ported intake and new cam and drive train mods

http://users.erols.com/srweiss/calcafhp.htm

http://users.erols.com/srweiss/calchpaf.htm

http://users.erols.com/srweiss/calcpchg.htm

http://www.wallaceracing.com/runnertorquecalc.php

http://www.z31.com/software/injector.pl

 

[Louis Bartay]

I read a post on another Corvette site about having to drill out a hole and install a piece of copper tubing for a good idle on a 52 MM TB. It had pictures and why this needed to be done on several brands of 52MMTB. So I have not bothered to but this and yes Grumpy I still have my screen in my stock MAF.

 

[96vetteLT4]

Which one

i'm considering putting the 52 mm on my LT 4 and for the guys that have them did you REALLY feel a difference. It's seems this forum and others to be 50-50 with the change. I want replies from guys who have made the change and found an improvement and those who did'nt. Also I kind of like the Holly over the BBK , quality looks a little better, again to those with Holleys let me know whst you think...and rember the corvette motto...items in the mirror appear to be loosing....G

 

[96LT1]

i'm with you , If you don't do major mods. all you will accomplish is over powering a valve train and connecting rods that will only stand 6200rpm MAX. Air in must equal air out at the same rate otherwise something will bunch up. You would not only need valve train mods but a complete exhaust replacement. If all a person wants is to maximize what's there don't over kill with probable catastrophic results. my 52mm. works great and it IDLES great, and it gets 35mpg at 70mph( imperial gallons, are 20% larger than US gallons)