Hi!
Which swap gets better MPG LT1 with EFI or LM7 5.3 carb?

 

Guys will claim lsx carbs will get mileage but id rather put money on lt1 efi since there will be greater control of fuel and spark inputs which are needed when shooting for max mpg

 

hands down the LT1 efi. LS1 efi tends to get a little better than the LT1 efi.

 

LT1 efi

 

5.3 with a well tuned carb knocking down economy as good as a lt1 still needs a cowl hood to run an air cleaner. Otherwise, odd comparrison. Great economy can be had from a carb, but efi as mentioned can have better tuning ability the is irrelevant to some and important to others.

 

Good point about the hood and cleaner. Not sure how tall the carb lsx setups are. Carb can get mileage but it would take a good bit of time to do it and still dont have the greatest control of fuel and timing but not sure how the lsx timing boxes work. Zone89 could tell. Can it control timing versus rpm vs map like in the efi systems?

 

So i cant use stock hood with lt1 setup?

 

You can use lt1 efi with stock hood it sits lower than the tpi intakes. No one said anything about it not fitting.

The carbed intakes may or may not fit. The lm7 lsx style intakes usually sit high up

 

Honestly depends if one is running fatter than the other throughout your RPM band...

 

What you guy thinks about ebay lt1 stand alone engine wiring harness kits?
http://www.ebay.com/itm/1994-95-LT1-...6fdefc&vxp=mtr
I have v6 camaro, i think its better use this kit than mess with v6 wiring harness?

Sorry for my bad english, im from europe

 

Why not stick with what you got and go with a turbo, just an idea to throw at ya? By keeping the V6 you'll get the best gas mileage possible when the engine is under vacuum.

https://www.thirdgen.org/forums/powe...o-time-v3.html

 

But what about 3.8 v6 buick turbo engine? I know guy who sell his good stock condition 3.8 engine for 600euro. Is this easy swap?

 

Yes, very easy swap. You can either run a V8 700R4 by using an adapter plate, or run the stock 200R4 with it. I would highly recommend the 200R4 simply because it doesn't lockout 4th gear at wide open throttle, but that's just me, as I'm a highway buff. For the computer look into Dynamic EFI's SFI-6, excellent price, and excellent product, or you can run the stock '7148 ECM, which is very easy to modify using a Turbo Tweak chip...

 

3.8 buick in fbody need custom fabricated engine mountings?

 

No, just adapting the bellhousing to the 700R4 transmission because of the different BOP pattern, unless you of course just run the 200R4 that came with the Buick engine. Remember that the 3.8 Buick Turbo came in the '89 Trans Am, it bolts right in. Very easy swap. Here is NeilB's Camaro w/swap, find his build thread on the V6 board...

 

You can disable 4th gear lock out with 700r4 using the 80's efi computer control. Retrofitting that to a buick gn ecm i am not sure. Lt1 stuff also not sure as they started gettin electronic trannies at some point

 

The only problem with that is that 4th gear is very weak in the 700R4, that is the only reason why I hesitate w/mine during higher RPM. Dana at ProBuilt would definitely have the fix for that of course. However, if he goes w/the 200R4 he won't have to worry about it...

 

True i just have yet to run into a situation where id want to be in 4th at high rpm.... I was doin 128 in the 1/4 in 3rd with plenty of room. No need to go faster. If so just gear it taller

200 does have a more favorable gear spread tho

 

That's cuz you haven't come across that arrogant GT-R owner on the highway yet...

 

Theres one around here from what i heard... Supras too. I have to worry alittle. Its why i still have 2.73 gears

 

I didn't know you were still running that tall of a gear ratio, where is your RPM at 80-mph?

 

I will be swapping but i have th400 trans so it helps on highway. 80 would be 2800 rpm by the tire size but my converter would likely be slippin a tad higher and id be on verge of boost lol

This new combo doesnt like tall gears. Turbos like load but not this much. 3.08 or 3.31 may be in order

Sorry for the threadjack

 

Where i can find wiring harness for 3.8 buick engine? My Camaro is 2.8 V6 or can modified my own car harness do work with 3.8 SFI engine? I need know easiest way to wire hareness.