BritishV8 Forum: TBI or Carb???

palmjeld
Paul Almjeld

(13 posts)

Registered:
12/30/2010 02:42PM

Main British Car:

TBI or Carb???

Posted by: palmjeld
Date: January 01, 2011 11:05AM

Happy New Year everyone. One of my cars is a '64 Sunbeam V8 (Tiger clone). I am thinking of switching out my Edelbrock 600 cfm carb for a TBI system. I'm presently running the carb over an Edelbrock F4B medium rise manifold. My engine is a 302 bored .030 over. I'm running a mild Ford Racing street/strip cam. All this goes through a C4 automatic to the stock Tiger rear-end. The car is very quick - at least by '64 standards. I am looking to improve the fuel efficiency, though, as I most often use it as a highway cruiser. Thoughts?

from sunny, cold, blustery South Dakota

Paul

MGB-FV8
Jacques Mathieu
Alexandria, VA
(299 posts)

Registered:
09/11/2009 08:55PM

Main British Car:
1977 MGB Small Block Ford, 331 Stroker

Re: TBI or Carb???

Posted by: MGB-FV8
Date: January 01, 2011 08:41PM

Paul, I'll chime in based on some personal experience. TBI fuel injection, because of its constant mixture monitoring will give you better driveability and fuel economy; horsepower wise should be comparable if the throttle body is properly seized. However, sequential multi-port fuel injection with long/tuned intake runners would be the better choice for economy and power.

There's lots more factors other than fuel induction that can enhance fuel economy, such as, gearing, tire seize, exhaust improvement, engine timing, choke setting, friction and drag etc., etc.,. What MPG are you getting now?

Jacques

Orange Alpine
Bill Blue

(45 posts)

Registered:
12/20/2010 07:36AM

Main British Car:
1967 Sunbeam Alpine 2.5 Ford Duratec

Re: TBI or Carb???

Posted by: Orange Alpine
Date: January 01, 2011 10:16PM

Hi Paul

Here are my thoughts:

It seems Edelbrock provides carbs with either economy or performance jetting. Do you know which you A) have, B) would prefer?

A change in rear end ratios is probably in order, do you know the ratio you now have?

Why TBI, why not multiport EFI? Here is a multiport step by step "How To". [www.therangerstation.com]

See you in September.

Bill

palmjeld
Paul Almjeld

(13 posts)

Registered:
12/30/2010 02:42PM

Main British Car:

Re: TBI or Carb???

Posted by: palmjeld
Date: January 02, 2011 08:46AM

thanks for the replies regarding the pending switch to fuel injection. I'd prefer to go multi-port but am not sure I have enough room under the bonnet for all the apparatus. Things are really tight on the Sunbeam. More research needed on that.

Rear end - 2.88 tough to get anything lower without going to AOD tranny. The final ratio on the C4 automatic is 1:1.

A tranny swap is a possibility.

Current mileage is around 17 when I behave myself on an interstate and stay around 65 mph. I'd like to boost that a bit, especially considering the rising cost of gas.

Carb is jetted for economy.

look forward to seeing you Bill. How's the Duratec project?

Paul

socorob
Robbie
La
(173 posts)

Registered:
09/17/2009 04:42PM

Main British Car:
1963 Sunbeam Alpine Series 2 Ford 2.8 V6

Re: TBI or Carb???

Posted by: socorob
Date: January 02, 2011 03:37PM

for hwy cruising overdrive is always a good idea.I went from a c4 with 3.55 rear end in my v6 alpine to a t5 with 4.11s and it turns over less RPMs at 70 now than it did before. I got the mustang V6 t5 so i could get the one with the larger overdrive gear. The 5th gear ratio is .68, so at 70 im turning about 2750ish. Much better drivability wth the t5 and fuel economy, plus sports cars should have a manual tranny anyway. Good luck with your V8, im sure thats a fun car.

palmjeld
Paul Almjeld

(13 posts)

Registered:
12/30/2010 02:42PM

Main British Car:

Re: TBI or Carb???

Posted by: palmjeld
Date: January 02, 2011 07:21PM

thanks for the reply. Yeah, it's a hot rod. Lots of power, especially from 3500 on up. I've had the car up to 120 on the interstate and it was still climbing. If I was 20 I'd probably know what the real top end is!

Paul

Orange Alpine
Bill Blue

(45 posts)

Registered:
12/20/2010 07:36AM

Main British Car:
1967 Sunbeam Alpine 2.5 Ford Duratec

Re: TBI or Carb???

Posted by: Orange Alpine
Date: January 02, 2011 07:33PM

The Duratec project is currently in pieces. Know anything about a Ranger M5 R1 tranny?

Bill

MGB-FV8
Jacques Mathieu
Alexandria, VA
(299 posts)

Registered:
09/11/2009 08:55PM

Main British Car:
1977 MGB Small Block Ford, 331 Stroker

Re: TBI or Carb???

Posted by: MGB-FV8
Date: January 02, 2011 10:55PM

Paul, what is the weight of your car and also the rear tire seize? IMHO, the car could see 20 MPG.

Jacques

socorob
Robbie
La
(173 posts)

Registered:
09/17/2009 04:42PM

Main British Car:
1963 Sunbeam Alpine Series 2 Ford 2.8 V6

Re: TBI or Carb???

Posted by: socorob
Date: January 03, 2011 02:06PM

Along the same lines, does anyone know of a factory tbi that can be bolted to a 4bbl manifold that can be megasquirted or something similar that flows 400 cfm or up?

MGB-FV8
Jacques Mathieu
Alexandria, VA
(299 posts)

Registered:
09/11/2009 08:55PM

Main British Car:
1977 MGB Small Block Ford, 331 Stroker

Re: TBI or Carb???

Posted by: MGB-FV8
Date: January 03, 2011 10:37PM

Try the early GM Chevy cars and P/U trucks 305 c.i. and 350 c.i. starting in 1986 up to the mid '90s. Also, the Dodge trucks (V-8) with 318/360 c.i. from 1987 to 90 something had a throttle body with built in injectors. Some minor modification (adapter plate) to adapt it to a 4 barrel intake may be required.

palmjeld
Paul Almjeld

(13 posts)

Registered:
12/30/2010 02:42PM

Main British Car:

Re: TBI or Carb???

Posted by: palmjeld
Date: January 04, 2011 11:49AM

The car weighs about 2250 lbs. The tires on the car are 185/70/13's. The 13 inch tires are standard for both Tigers and Alpines. Many owners have modified their cars and run 14 inch tires. Some have even gone to 15 inch.

The Chevy 350 throttle body is often used in the swap between carbs and TBI. There are a number of different electronic control systems that can be used, including the original GM. Megasquirt gets good reviews.

If $$$$ was no issue I'd install an AOD tranny, upgrade to 14 inch wheels and install a fuel injection system. At this point I think the least expensive part of this will be the switch to the TBI injection.

later

Paul

joe_padavano
Joseph Padavano
Northern Virginia
(157 posts)

Registered:
02/15/2010 03:49PM

Main British Car:
1962 F-85 Deluxe wagon 215 Olds

Re: TBI or Carb???

Posted by: joe_padavano
Date: January 04, 2011 02:01PM

"Along the same lines, does anyone know of a factory tbi that can be bolted to a 4bbl manifold that can be megasquirted or something similar that flows 400 cfm or up?"

Um, how about a factory Ford TBI as used on the mid-1980s 302s?

MGB-FV8
Jacques Mathieu
Alexandria, VA
(299 posts)

Registered:
09/11/2009 08:55PM

Main British Car:
1977 MGB Small Block Ford, 331 Stroker

Re: TBI or Carb???

Posted by: MGB-FV8
Date: January 04, 2011 06:30PM

Thanks Joe, I forgot about mentioning the Ford TBI. Paul, if you could find a 1985 LTD or full size Ford/Mercury car with a 302 that would be another choice although I can't remember if the EGR valve (with position sensor) was part of the TBI or bolted to the plate underneat it?

mgb260
Jim Nichols
Sequim,WA
(2465 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: TBI or Carb???

Posted by: mgb260
Date: January 04, 2011 11:20PM

The thread on Rover with 2 downdraft 2 bbl carbs on this page has a picture of mid 80's Ford TBI. Holley 2 barrel bolt pattern.

Edited 2 time(s). Last edit at 01/05/2011 02:35AM by mgb260.

Orange Alpine
Bill Blue

(45 posts)

Registered:
12/20/2010 07:36AM

Main British Car:
1967 Sunbeam Alpine 2.5 Ford Duratec

Re: TBI or Carb???

Posted by: Orange Alpine
Date: January 05, 2011 08:33AM

Paul, why go to 14" wheels? I felt the same way, but decided to go whole hog and am going 15". I think that in a few years the 14" tire market will be as dead as the 13" is now.

Be aware that 6" wide Saab 9000 wheels are a perfect fit for the Alpine. Correct bolt pattern and off set. Most styles are 15", a few are 16". Add some P195 tires and you would be in business. Get genuine Saab wheels, I think the aftermarket wheels are "close", but we know that "close" is not always good enough on an Alpine, right?

If interested, check out the listings on Saabnet and car-parts.com. The used wheels from these sources seem to be very reasonably priced.

Bill

socorob
Robbie
La
(173 posts)

Registered:
09/17/2009 04:42PM

Main British Car:
1963 Sunbeam Alpine Series 2 Ford 2.8 V6

Re: TBI or Carb???

Posted by: socorob
Date: January 05, 2011 11:20AM

ive read that the gm tbi is around 450-500 cfi, im trying to find the info on the ford. There is a good write up on the gm here.

[www.diyautotune.com]
I think i may have hood clearance issues with that, but ill go to the local upullit yard to see if i can get some accurate measurements. Summit sells a plate to mount the gm tbi to a 4 bbl intake.

I have 15 inch vtos, they are 4.4 backspace, look nice. If i have to do it again, id go with 4 inch backspace for the rear, and a little more on the front, to get the wheels more inline. Heres what it looks like. I would probably go to 16 inch if i had it to do over, 1 inch wouldnt make it look that much different, and i think in the future sport tires will be better supported.

[www.youtube.com]

palmjeld
Paul Almjeld

(13 posts)

Registered:
12/30/2010 02:42PM

Main British Car:

Re: TBI or Carb???

Posted by: palmjeld
Date: January 05, 2011 11:06PM

Nice youtube Alpine! The wheels look good on the car. How much trimming did you have to do, if any, to get lock to lock turning with no rubbing?

The guys at diyautotune are very helpful. Matt was quick to respond to my questions and helpful. When it's time for purchase that's where I will go.

socorob
Robbie
La
(173 posts)

Registered:
09/17/2009 04:42PM

Main British Car:
1963 Sunbeam Alpine Series 2 Ford 2.8 V6

Re: TBI or Carb???

Posted by: socorob
Date: January 06, 2011 10:11AM

I didnt do any trimming, but i think the PO rolled the front valance already. These tires are less than 1/4" taller than the 13 inch tires that i replaced, so not much difference there. If i can find a suitable tbi that will fit under my hood, ill go with diyautotune also, theyve answered every question ive had and have been very helpful. Im having trouble find how much the 302 tbi cfm rating is, and the height of it. I have limited space, 5-3/4 inches from where the carb sits on the manifold to the top of my aircleaner which i think almost touches the hood, so i may not be able to find anything to work and have to stick with a toilet on top of my engine.

Bill Young
Bill Young
Kansas City, MO
(1337 posts)

Registered:
10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

authors avatar

Re: TBI or Carb???

Posted by: Bill Young
Date: January 06, 2011 02:04PM

Paul, I think you should be getting a bit better with some type of FI either TBI or MPFI. I'm running a much smaller engine of course but my 2.8 with MPFI, a T5 with a final overdrive ratio of .76, a 3.43 rear gear, and 205 60 13s I get around 25mpg on the highway. The effective gear ratio in 5th is 2.60 so your 2.88s should be close. I'd think you would probably get around a 3 to 4 mpg increase with the injection, but an overdrive trans would make far more difference. Increasing the wheel diameter probably won't buy you much as you are effectively limited to overall diameter by the wheel wells anyway.

rficalora
Rob Ficalora
Willis, TX
(2764 posts)

Registered:
10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

authors avatar

Re: TBI or Carb???

Posted by: rficalora
Date: January 08, 2011 10:02AM

RE: which i think almost touches the hood

A quick way to find out how much clearance you have is to get some kids playdo or something similar. Make a ball a little bigger than you think the space is, put it on top of your air cleaner & close the hood. The hood will flatten the playdo & you can then measure how thick it is to know for sure how much space you have. Remember to look at the crown of the hood & where any cross braces are to decide where to put the the ball so you'll catch the area with the least clearance.

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