turbo q'ns

[karottop]

hi, I have recently aquired a 1989 a20a4 accord EXi and am looking to turbo it. and I'm still a bit vague in some areas.
Engine management. What do you guys use for fuel and spark control?
what is the advantage of a b20a over a20a4 from a forced induction point of view (obviously an extra 4 valves) is it stronger at all?
what sort of power can I expect from both with a stock rebuild?

we have plenty of b20a accords and preludes just sitting around here in NZ so a conversion shouldn't be too expensive but from what I hear there are 101 different engine/tranz configurations for the b20a's.

and as an afterthought
it has 190000 kms on it and from what I can make out it spent most of those being thrashed in one degree or another.
any and all feedback would be appreciated.

[A20A1]

I would stick with the A20's iron block and rebuild it... but not with stock parts.
unless you're not planning on going above 5-7psi, but even then why run the risk of having to rebuild the engine again.




I'm positive there are more informed opinions then mine though.

INTERNAL ENGINE UPGRADES
compression Calculator
http://www.c-speedracing.com/howto/c...c/compcalc.php

- PISTONS
--- WISECO
--- DIAMOND

Diamond pistons
- Bore your Cylinders first ONLY as much as you need to and then use those specs to order custom pistons.
83mm bore is preferable (stock bore is 82.7mm)

- Get the Normal Chromoly Total Seal Ring Package instead of the Gapless
here is some discussion on why not to get gapless
https://www.3geez.com/forum/showthread.php?t=26216

NEED HELP WITH YOUR DIAMOND PISTON SPECS?


- RODS
THREAD ON EAGLE AND CROWER RODS

--- EAGLE @ IMPORTPARTS.COM
* According to eagle the lowest priced place to get them is importparts.com
* This eagle Rod is a direct fit into the A20A engine. the only change required is to enlarge to a 21mm wrist pin from a 20mm wrist pin. Diamond pistons will accommodate this change here's the eagle part number
* Part Number - CRS5394a3d - Eagle rods

B18A / B18B DOHC non-VTEC
CRS5394A3D "ESP" H-Beam Connecting Rods

CROWER
B18A / B18B DOHC non-VTEC


- BOLTS FASTENERS
--- ARP

ARP Head Studs, part # 218-4703
http://arp-bolts.com/Catalog/Catalog.html
For '98-'02 Miata. Same as ours.

- GASKETS
Cometic head gasket
- Send in a new A20 Gasket and have a copper gasket made from it.
https://www.3geez.com/forum/showthread.php?t=56658

[MessyHonda]

send me a b20 with a manual gear box

[karottop]

so what do I do on the fuel management side of things? it'll need a new MAF meter but what do I use for an ecu?

[bobafett]

unless the NZ cars are significantly different than the USDM A20A3 motors, you don't have a maf sensor you will have a map sensor. you may want to upgrade to a 2 or 3 bar map sensor depending on the boost levels you plan to run.

the stock ECU is worthless, it can't be reprogrammed and doesn't have electronic timing control.

for management, there are several choices.
the cheapest, and least effective would be to get an SAFC of some sort to control fuel. You may also need to upgrade the fuel system by getting a larger fuel pump and certainly won't get very far on stock fuel injectors. A popular option is to run turbo dsm injectors (450cc) because at least stateside they can be found for $50 usually.

An SAFC will be able to handle the fuel adjustments, but you will still need to play with spark.

While using your stock ECU the only option is to run a device that modifies timing based on manifold pressure. A common part to use is an MSD BTM (boost timing master I think). cost should be around $500 for these parts

This is a fairly crude setup and the tune will be your weakest link, but should be good for around 10psi. if you plan on boosting much more than that I would start looking at some more elegant solutions.

other options range from obd1 conversion, or some form of standalone engine management. cost is probably $500-$4000 depending on what you choose. however the weak link probably would be mechanical and not a shit tune.

EDIT: i may be wrong and maybe A20A4 NZ cars use an obd1 ecu but my hunch says thats not the case...

[Hauntd ca3]

if you are a kiwi, buy a link ecu
they are not terribly expensive for a fully programmable and depending on the model you get
i think they can run up to 2 bar boost with the built in map sensor.
the flash ones will do pretty much all you could want them to do
keep an eye on ebay or trade me and one will turn up
b20a's are cheap
buy a wreaked si 3g and do the conversion