JDM B20a max bore

**mykwikcoupe** · 07-05-2003, 01:27 AM

Okay so please dont say do a search. As I am sure most of you know about my swap in progress so I have another planning question.

It is a turbo JDM B20A running with a garrett T25 turbo probably in the 8-12 psi range. I am planning 3" exhaust from the HKS BOV back with high flow cat and I have no idea of muffler(any suggestions that wont give me the ricer 2stroke sound would be cool). I would like to say that I running an intercooler but havent found a good routing spot yet so who knows.

Anyway the question is what is the max safe bore limit of the B20a. I would like to bore it out a little and keep the same compression and go with the turbo that has been desribed. I know that the ITR and CTR pistons work but will they work with this overbore or should i go with a custom made piston to keep the same compression. Also I was planning on just shot peening the factory rods with a de-burring and probably a polishing while Im at it. With this sufice or while Im haveing the pistons done just do the rods also. Thanks for all your help on this guys I really appreciate it. Im and old school chevy guy so This this the first Honda Ive rebuilt. Ive done a couple engine in the past but you know chevy, all the works done for you you just order what you need for the goals and put it together.

Also B20aturbo has turned me onto a rebuild shop called goldeneagle.com I was planning on sending them the block for the gasket and sleeving. If I am doing this then damnit im doing it right. Ad far as pistons Ive always been partial to wiseco and venolia. Heard good things about ross racing also.

**Mike's89AccordLX** · 07-05-2003, 03:32 AM

Are you going to have it carbed or fi? I was thinking about putting dual weber 45's on my jdm b20a. I've heard that it's not good to turbo a carbed motor though. I don't really want to convert everything to fi, that's why I'm going with the big carbs.

**mykwikcoupe** · 07-05-2003, 03:37 AM

well the turbo ones FI the other is carbed. Yes I have 2 b20a engines. The carbed on I was thinking of going with 2 40 dcoe webers but will most likely just go with weber 38/38 conversion. Its a milage machine only and I dont think the stock crappy keihin will keep up with the B20a.

If anyone here knows 89 lx sedan with an auto. I dont see the cable that runs to the tranny in the front of the car. Does this mean that I cannot use the weber conversion on the car. I have done the search and havent found this answer. thanks Mike

**Mike's89AccordLX** · 07-05-2003, 03:45 AM

Are you trying to figure out how to rig up the throttle with a weber b/c you have an auto? I would talk to A20A1 if you have questions about hooking up a weber to an auto tranny. Note: you have to use parts from the stock carb, so just don't toss it

I wanted to convert the car to FI but I was getting confused with all the stuff I would have to do and I figured carbs would be easier. But I really want to turbo the motor and I was told it isn't good to turbo a carbed motor. I wish I could figure out a way to supercharge the jdm b20a.

**mykwikcoupe** · 07-05-2003, 04:08 AM

jackson racing makes a supercharger kit for the b16-b18. It is possible to make those manifolds fit the accords but then your back to FI again

**Mike's89AccordLX** · 07-05-2003, 04:17 AM

I might have to shoot the breeze with A20A1 b/c I thought he might be working on a supercharger to work with the A20A1. So maybe I could try it on a carb. I know that there were some motorcycle carbs that might work. I don't really want to do the FI swap, maybe I will just pay someone on here to do it for me. I'm just too lazy to do all that wiring and stuff. I read the how to like 6 times and I just get a headache

**mykwikcoupe** · 07-05-2003, 04:21 AM

I was debating it myself for quite a while. The noice thing is the entire swap is plug and play. If you set aside a few days away from work and that cute thing you have standing in the front of your car you should be able to finish it. I myself just bough a second accord so now I have 1 FI and 1 carbed. Thats just me though.

**Mike's89AccordLX** · 07-05-2003, 04:27 AM

I wish I could find someone to buy my accord so I could buy a lxi or sei. That would be a lot easier

My parents would kill me if I bought another 3G. And if I did the efi swap I would put in all new parts so I would need a new gas tank, fuel pump, lines? (been awhile since I read the how to) Maybe it wouldn't be so hard. I bet if I could get a parts list from someone rather than have me try and guess what I would need. I wish I could afford to have Sean come to MN and help me. I know he would be one of the Gods that could help me out. He told me that if I did the swap I would want the Prelude ECU (B20A5) b/c of the fuel mapping and gibber jabber that I don't understand. I have my school to do all the work in so I have access to the tools for it. I just need to know what I need (everything) for the swap and go out and buy the goodies.

**wprocomp** · 07-05-2003, 12:31 PM

I would say .020 or maybe even .030 max,but I would sleeve the block just to be safe,that way you can play around with the turbo and not worry about shooting a piston out the side of the block...my freind ran a B16a with a .020 bore with 12psi of boost from a T3/T4 and it runs fine without any sleaves.

***carotman*** · 07-05-2003, 01:18 PM

the block is already closed deck

**Sean** · 07-05-2003, 09:25 PM

huh i can run 25 psi of boost without sleeve and a .030 overbore. funny hwo cast irpn is so much stronger

**mykwikcoupe** · 07-06-2003, 01:11 AM

ok cartot youll have to excuse the stupidity of my question here but by closed deck I have the impression you are reffering to the deck height. IE head clearence to piston height. That I have no intention of changing except at the machine shop when they do there resquare and such with line honing and alll.

I have heard the remarks of oped deck or closed deck could someone please reiterate