I have a 91 prelude Si

We may earn a small commission from affiliate links and paid advertisements. Terms

R

RobertF1

New Member
I have a 91 prelude si which i have made a race car out of it and i threw a rod i had the b21a1 in it and bought a b20a5 what is the diference and do i need to change any parts to make this conversion.

What can i do to the motor to add horsepower with only using stock honda parts because that is the rules
 
Last edited:
should bolt right in may need to swap out intake manifolds and exhaust but un sure on that.

im assuming this is a roundy roundy car. I would try geting a macine shop to lighten the flywheel while you have the car apart. Porting the head and intake if rules allow you could also do some piston changes with oem pistons from a diffrent engine. Do you have link to the rules for your local track or do they go by the standard CRA rules let me know ill help you out iv got 2 guys runing at my local track and one of them got second in points this year
 
I thought the B21 was not interchangable with other B series. :shrug2:

Maybe I just need to put the bottle down?
 
just keep your B21a1 stuff and use the B20a5 long block and it will fine. The B20A is a good overall motor, while the B21a1 was good for low to mid power range.
 
newb said:
I thought the B21 was not interchangable with other B series. :shrug2:

Maybe I just need to put the bottle down?
Click to expand...

The 88-91 Preludes had two engines available, the B21 and the B20A5. Neither of those motors are parts compatible with the other B-series engines...
 
well couldnt find the rules but if you are allowed to use any stock parts get you a set of pistons for a 2000 acura integra typeR or a 1999civic SI. The integra typeR pistons will net you about 11.9:1 compresion. If you mill .020 off the head and you are at 12.5:1 get you a intake cam from a B18B which is a non vtec integra form like 1999. if you do the piston change run 100octane or higher and get a set of 390cc injectors from a automatic turbo eclipse or talon. car will run a little rich but you should be ok and still fall into the stock parts rules with a unmodified ecu
 
You must log in or register to reply here.
Back
Top