matt07GT

I am getting a JLT/XCAL from Breenspeed...should I also get a BBK twin 62mm Throttle body...or a spacer? Would it make any difference?
Also, does anyone know the mm's for the stock throttle body?

Gene K

NO.

Bigger TB usually only helps when you start making major power.
Also aftermarket TB can cause all kinds of issues.
Because of the "Drive by Wire" Throttle the car has failsafes to avoid
a run away car if you get electronic interference. If air flow doesnt
match the throttle input it goes into "limp" mode.
The best TB conversion seems to be the factory GT500 TB.
It usually is most effective on draw through (Screw or Roots) style blowers at high boost.

Dyno Test have been inconclusive on the spacers.

Dyno Proven mods are the Steeda (Formerly FRPP) Economy CMCV Delete Plates (Tune needs to be set up for them) and Steeda
Underdrive Pulleys. I assume since you didnt mention Off-Road H/X-Pipe you live in a local where this can be problematic.

The Pulleys dont show that much on the Dyno but seem to help the 1/4 mi ET more than they should.
I think it has more to do with the inertia of trying to spin the accessories up rapidly than actual steady state load.
IE they would help acceleration more than top speed.

acascianelli

BBK TB: Useless unless you're running turbo/supercharger. If you do get it, you need a dyno tune to run one properly, and even then they won't give you much if any added horsepower.

TB Spacer:100% Useless, the whole idea of these is a relic of carburated and TBI engines.

I've read that UDP and delete plates are worth about ~15hp combined. I installed my UDP, delete plates, and a new tune (upgraded from canned Diablosport tune to Bamachips race tune) all at once so its difficult to tell which part gave a certain amount of power. But I did notice a big increase in response and power, about as big as when I first installed my intake and canned tune.

matt07GT

Thanks for the info...looks like I can use the $250 for something else

onederful100

definately not. i got a spacer it does nothing at all. also if you want to put on a plenum cover it wont fit w/ the spacer on there. but bottom line is the spacer and the TB is a waste IMO. i would suggest the plenum cover for under 100 bucks just for looks.

acascianelli

If you want to spend that $250 on mods that will add power; you could do UDP and delete plates but you would have to look for them used, or you could buy a o/r H or X-pipe. Or you could just do all 3.

On second thought, that O/R midpipe might not be a good idea with those Loudmouths.

matt07GT

Would it be too loud???
Also....what exactly is the purpose of delete plates?

acascianelli

Yes, it would be very loud. The only thing that would make it even louder is longtube headers.

Delete plates remove the charge motion control valves in each intake runner. They are originally designed to help low-end torque and to improve fuel economy. If you remove them, you will lose some fuel economy, and possibly some low-end torque; but since they require a tune, you can usually gain 5-8hp throughout the entire rev range. They were a great mod before when they only cost like $80 from FRPP, now FRPP doesn't sell them anymore and the only place you can get them is from Steeda and they cost $140. I would suggest buying a set of them used. I was fortunate enough to find a set of the billet plates (normally $300) used for $90.