Throttle body injection, worth it?

[merc-blue]

I have spent all day today reading whatever i can on TBI, after it was suggested to me by oldcorrolas
and now im really keen to setup a NA TBI 3T-G.
I have a few questions
Is it worth the money?
for 1K your pretty much setup hardware wise just need to get a ECU and other small bits, this 1K would come from my engine parts budget, instead of forgies and chromly rods i would be going Hypereutectic pistons and shot peened factory rods, i would also be not getting as much headwork just standard clean up work and no opening of ports and so forth, the cheaper piston and rod combo should still have no problem in my application, i would still be going ARP studs and all the normal performance bits i would also have to cut some of the cost out of suspention no sway bars or strut braces for now, but still with knoi yellows nolophane bushes and nice springs

second question what style?
i think a dual 40mm throttle body (fit on a existing manifold) would be sweet, agree?
next question is length 30, 93 or 118mm if i wasnt going to run trumpets but a airfilter in this style LINK
I have NFI on what would be best but the 118mm appeals as i read that a longer body is good (but may have misunderstood)
megasquit computers look arite and price is right in kit form but how hard to write a map/profile specifically for TBI as opposed to regular injection. are the dyno guys gonna look at it and go WTF we cant touch that or be sweet with it?

info would be good
Cheers

[slide86]

do you mean having the injectors at the end of the trumpet and injecting the fuel into the trumpet?

Typically the longer the inlet tract modifies the torque curve. Hense the TVIS type system. The falcons also use a similar type system that opens longer runners in the RPM range to modify the torque curve.

I think that the internals that you will be running will suit your application fine. Have you thought bout balancing and blueprinting the engine? this could be a valuable step if you want to create a high revving atmo engine. The head is also quite an important part of an atmo engine and would be worth modifying

I havent done this setup myself, so i cant comment on how it will perform.

a decent dyno shop should be able to setup a map and tune the beast, best to ask and shop around tho!

[merc-blue]

slide86 i would consider blueprinting if i had the money im running a thin line budget wise ATM, pretty much the choice is a more agressive engine (more head work and better rods) on carbies or a more sedate engine on TBI,

whats going to be most reliable and still get good power?

I guess i will go the middle size (if i go TBI) then that way i have play in both directions

[oldcorollas]

i meant TBI as in a single throttle body, to replace a single carby (usually downdraught) like form Ford falcons etc..

the benefit is that if you are runnign a blow thru turbo setup, it's almost as good as port injection (except for fuel distribution), and a shitload better than suck thru or blow thru carb.

i was NOT meaning individual throttle body injection

grab a TBI throttle body/injector from a falcon (not sure what years), and an MS, and you can do for well under $1000.

if you are talking ITB's, then thats a completely different kettle of fish.

if you are only doing NA, just keep the twin carbs (assuming 2T solex type or whatever)

chromoly rods? why? forgies for NA? why?
look to the Venolia 89mm pistons etc for inspiration.


ideally, you would have ITB injection. then after that, twin carbs, then after that, single barrel TBI, and then after that.... downdraught carb..

i think you may have misunderstood what i meant (which was in relation to turbo setup anyway )

edit: to be honest, from the level of your questions so far, i think tuning an MS or even building one may be beyond you.. perhaps.... you need to know what you are doing and why.
T series engines have been beng modified since the 70's.. you have around 30 years of midification experience to draw on. if you can't find answers to your questions easily.. there is something wrong.....

[slide86]

yeah, i wasnt sure either. initially i was thinking of the falcon type setup....i was not aware there was talk of turbo.

the model falcon is EA. Camira and early barinas also share the same type setup. But i would think that the falcon type would have the largest diameter and the best flow. Being that it is the largest displacement engine

[merc-blue]

edit: to be honest, from the level of your questions so far, i think tuning an MS or even building one may be beyond you.. perhaps.... you need to know what you are doing and why.
T series engines have been beng modified since the 70's.. you have around 30 years of midification experience to draw on. if you can't find answers to your questions easily.. there is something wrong.....

To be honest I agree mostly, i have no problem with the physicality of building a rebuilding a engine, checking clearances and making sure its all right, but when its time for tuning a engine or building a performance engine them im compleatly lost,
when you said TBI I thought Jenvey throttle bodies and manifold and so forth, oh well.
when it comes the choice of cromoly rods and forgies, well, if you have a high compression engine being revved out i would rather pay more and not have my engine killed with a snapped conrod.
i think i might just stick to the initial plan of a more agressive NA twin 40mm solex carbed 3T-G, should have plenty of power and there is nothing i dont already understand required, although i might be going overboard on some of the parts

[MWP]

IIRC the Mitsu Starion also has TBI.

TBI is an easy way to setup EFI on a carb'ed car, but it wont have many of the advantages of multi-point injection.

TBI can still be better than side-draught carbs... how many people with side-draughts actually have them tuned correctly?? Not many.

TBI + Megasquirt = super cheap EFI.