My 89 L03 is stock, was wondering if this plus headers and 3" catback would make noticeable difference.

Xtremefi 46mm TBI throttle body PC Chrome 590cfm/340hp


http://cgi.ebay.com/ebaymotors/ws/eB...fvi%3D1&_rdc=1

 

You should do the tbi mods since the tbi i think its for when you have a high powered engine and i don't think your l03 has alot of power instead wih the price of that buy a lt1 cam and headers and exhaust how you mentioned then you will notice a big difference.

 

No help. way to confirm stock TB is too small is to datalog engine and montor the MAP sensor. restriction shows up there.

 

The LO3 stock TB is no restriction up to around 280hp. Under this power level there is not relly anything to gain, other then a new good looking TB.

For TBI parts much better to get your parts here http://stores.ebay.com/TBIPARTS/_i.h...4.l1513&_pgn=2
http://www.turbocity.com/default.php...b248a1f6b6db07
http://marine-performance-parts.com/index.aspx

 

So you'r saying it's possible to get to 280 hp with a L03?

 

Probably if you change the heads and cam also a good tune which is from what i have heard.

 

"The LO3's stock TBI with 25-28psi fuel pressure is capable of 280hp, but you already know heads, cam, exhaust, fuel and tune must be upgraded.
For 280-340hp a "ported" 46mm TB should be anogh, 65,68 and 80lb injectors with correct fuel pressure will work"

What's the stock fuel pressure on L03? At what point you would need to change the fuel pump?

 

I don't think I made it sound that way.

For that hp the LO3 would need aftermarket heads (maybe some ported heads could do it too), cam, EBL flash to tune it, VRFPR, TPI fuel pump and headers. Wich is not a LO3 anymore.

I was saying the LO3's stock TB flows around 450-480cfm depending on who's source and it will become restricting only at around 280hp.


I upgraded to turbocity's 46mm TB wenn I had my LT1 cammed LO3 with full exhaust and everything.
The 46mm TB didn't make any noticeble difference as far as performance, over the stock 43mm TB.


I hope you will understand it better now.

 

11.5-12 psi

TBI fuel pump could be ok up to 14-15 psi.

 

I just put CFM Technology's 46mm on mine, and it did make a difference, BUT my old TB was wore out.....With all the other bolts ons, and mods the car runs really well.....Cant wait to get to the track, and see how much of a difference there is from the last time I had it there...

 

its all in the tune!!!!!!