Mechanics

B2200 CARB QUESTION

1987 Mazda Truck

I have a 1986 Mazda B2000 and an '87 B2200. Both trucks have been modified with Weber 2bbl carbs and header exhaust. The '86 had approx. 120k on the engine when mods made. Mileage went up to 27-30 mpg at 70mph and top speed to 97 mph. '87 truck had mods made when engine was rebuilt. With 20k on new engine, mileage remains around 23 mpg. Top end is about 83 mph, and truck will not surpass 4k rpm in 5th gear. Why such a difference? Annoying as the '87 is the one I've sunk the restoration money into.
Also, any Mazda B-series clubs out there?
Thanks.
Avatar
R90Baron
February 18, 2007.



Need more info to tell u why. Also gear ratio makes a difference. Send me more info on the engines. Imsg me andi'll follow up

Tiny
Kin chan
Feb 22, 2007.
Both the '86 B2000 and the '87 B2200 have the same gear ratios according to my repair manual and the owner's manual. The '86 had the carb and header mods in early 2000, and showed a very noticable improvement. Engine had ~ 130k miles at the time. Now has ~190k miles on engine, biggest problem is occaional carb iceing.
" 87 B2200 was intended to replace Ol' Reliable. Engine was proffessionaly rebuilt 20k miles ago and carb and headers installed at that time. Emissions plumbing has been recently removed as an experiment, but mileage hasn't improved, nor has top speed. Town mpg is 19-20 and highway is 23 compared to 25 and 30 for the older truck. B2200 will not exceed 4000rpm in 5th gear. Thanks,
Will

Tiny
R90Baron
Feb 22, 2007.
First of all, are you looking at the gages when you say that it won't go above 4000 in 5th gear? If you are, that's a mistake. You may not believe it, but the tac is somehow linked to your truck's vacuum system. Secondly, the Mazda b-series truck's numbers actually refer to the size of the engine up until the late '90's(b2000 had the 2.0, b2200 had the 2.2 and so on) Have the vacuum and emissions controls re-installed, checking for gravel or dead bug parts in the vacuum pots and such. After they are replaced, watch the tac when you start the truck and rev it at idol. You should see a difference.

Tiny
HellCat18
Mar 30, 2007.