I've got a 89 4ws prelude with a b20a5 that I'm in the process of rebuilding all bearing gaskets rings ect, its a pure track car but i can't do to much to the engine with out taking lap penalties. swaps would mean a lot of laps so can't do that.

i would like to boost it but couldn't find to may threads on almost bone stock b20a being boosted. I'm pretty sure that rods are going to be the week spot, i am resisting going with h23 rods they are slightly shorter and i believe will ruin my squish zone.

any idea on what boost i can put on the stock rods, it has to last 24 hours of racing before it will be rebuilt again so i don't care if its hard on the engine only if it breaks the rods, we won't be going over stock redline and run 94 octane. we will have an intercooler, and bigger injectors, variable fuel pressure regulator, ill try to keep it pretty rich (12.2:1), won't be chipping to tune the ecu, its a pretty small turbo. thanks

(rule of thumb with most hondas seams to be safe about 7-8psi long as you don't have knock does this seam rich to you guys)

any other tips about this car would be great

 

H23 rods are identical to the B20 rods, except a bit more stout. A worthwhile upgrade.

You could get b21 pistons and bore the block to 83mm. It is still a factory piston and would give you a little more compression and displacement.

12.2:1 isnt too bad.

 

read some guy talked to a rep at JE pistons and they told him

B20A5 rods are 142.75mm(5.62")
H23A Rods are 141.5mm(5.57")

the squish area of piston is usually as little as .04 of an inch, unsung h23 rods would make the squish area .09 inch instead. i worried this might be enough of a difference to hurt my engine. maybe i can get a thin head gasket and be ok.

 

The measurements I have are

b20a5 = 142.5 mm
h23 = 142 mm

I have built a few of these motors, the last one making over 400whp....(a lot for these motors.) I can tell you the rod is nearly identical.

Also, the f22 rods are the same. F22 = H23 = B20A5

Remember that most those guys you talk to are just sales reps. No real experience.

 

yeah but you said almost identical. but its half a mm shorter and that will indeed change my squish area making it larger and i personally want it smaller. ill just shave down the head. so that i can get a squish zone of .035 which i want.
do you think this is a good idea
do you think i can run 8psi safe for 24 hours do you think 10psi would ok.

 

Yea, I agree milling the head should take care of any concern you have.

I think 10psi is perfectly safe, if the tuning is done decently. Make sure the AFR are consistent and maybe pull a little timing.

Another worthwhile upgrade is to remove the IAB plate in the intake manifold and cut out all the butterflies and webbing. Do the same on the upper plenum. Then reinstall.

 

great ill keep it pretty rich and retard it a few degrees. really glad you told me about the IAB and the butterflies and webbing. i wouldn't have known.

 

also after i rebuild the engine should i break it in naturally aspirated and then turbo or should i go ahead and put the turbo on it and then start to break in the rings and bearings.

 

Break it in with the turbo on. Just dont let it sit and idle. Get out and drive it and pull some vacuum. (i.e. go to say 4k rpm in 3rd gear and let off the gas, allowing the engine to slow itself)

 

ok thats what i thought, just checking thanks, oh any recommendations on injector cc an online calculator told me about 450cc. could i us 350cc injectors

 

450cc will be fine.

 

can the stock fuel pump handle it.

 

Injector size is directly proportional to HP goal and dependent on the fuel you use.

I put down 469 @ 15psi with 1000cc injectors maxed out, because I'm running e85. On pump gas I would be able to go to 600 or so, e85 is better to me because it prevents detonation.

 

Very true, but he stated the fuel and hp goal.

 

thanks guys for the help i plan to be running 460cc injectors and not sure if I'm going to run 8 or 10 psi. i might run 8 just to be safe because it is a long race.