20b engine

[gez]

Hi guys new to the scene just came on here to pick your brains if i may, i.ve had my rx for 18 months now and looking for a 20b engine for a project anyone know for one for sale or anyone done the conversion for any info .
thanx gez

[KaosMan]

You're looking at an expensive swap. You will need custom mounts/modified subframe, aftermarket EMS, etc etc. Expect to spend $10K and that's doing the labor yourself. Its not for the faint of heart.

What year & model 7 do you have?

[gez]

Hi i'll be doing most of the work my self i'm a mechanic. the car i have is a 94 tt mods are apexi air filters,exhaust,power fc and fmic greddy got a budget of about 8k
thanx gez

[KaosMan]

You'll need the Hinson 20b subframe which allows for a straight drop in and moves the sway bar. Its about $1250.

PowerFC won't work with a 20B. Plan on a Haltech E11v2, 6 LS1/2 coils, and 3 bar MAP sensor. Here's a general list to give you an idea, assuming you're doing ALL the labor:

Subframe: $1250 (http://www.hinsonsupercars.com/p-23-20b-3-rotor-equipment.aspx)
20B Longblock from a reputable source: $4000
Haltech E11v2 EMS with 3 MAP sensor: $1700
LSx Coils (x 6): $320
Custom spark plug wires: $125
Custom DP for 20B twins: $100 approx
Fluidyne radiator - bare minimum for adequate 20B cooling: $400

If you're gonna run stock boost and not increase it - which I highly doubt if you're going to all this trouble - you're gonna need a worthy clutch. 6-puck & 4-puck clutches will only hold so much power, they will save you money but hold you back. IMHO the bare minimum for a performance 20B is the Exedy Hyper Twin Plate clutch.

Cheap clutch: $500
Exedy Twin Plate: $1400

So on the low side you're looking at $8395 with the low power clutch, and $9295 with the clutch that can take the abuse.

If your 3rd gen is a Touring model, plan on getting a twin oil cooler setup. You will cook a 20B with a single FD oil cooler!

It is very very important to get a good 20B unless you plan on rebuilding it first. If you have to do this it will be a considerable expense to do it right...$1200 minimum in parts if the cooling seal lands are intact and the engine didn't shit an apex seal. Look for "C" and "D" series engines...they are stronger. You can find 20Bs for the $2000s but its gonna be an undesirable A or B code and/or its gonna have a blown apex seal.

I don't know your mechanical abilities but like I said this is a difficult undertaking. Aside from the mechanical aspects, you need to be able to wire and configure the EMS...whether it be Haltech, Microtech, Wolf3D or MoTeC. This is not easy by any means if you've never done one before. If you get stuck here or have a shop install the EMS factor in another $1000+ in labor.

Hope this helps
(From someone who's building a 20B for a friend's FC)

[gez]

thanx 4 the info much appreciated ,the rx i have is the type r,i was thinking along the lines of modifying my 13b with a 20b crank and an extra rotor after reading about it on the net has anyone done this succesfully any info would be great.
thanx gez

[KaosMan]

thanx 4 the info much appreciated ,the rx i have is the type r,i was thinking along the lines of modifying my 13b with a 20b crank and an extra rotor after reading about it on the net has anyone done this succesfully any info would be great.
thanx gez

You mean R1 or R2?

The 20B uses a special intermediate iron, the "2nd" iron in the 4 iron stack, that has both a secondary & primary intake port and is set up for a stationary gear for the front rotor. This iron, brand new, is $2300. The eccentric shaft is also expensive, somewhere in the neighborhood of $800. Aside from needing a rotor housing and rotor for the front, you'd also need to open up the ports on the 1st, 3rd, and 4th irons to match the large 20B port on the 20B 2nd iron. Then you also need the special tension bolts for the 20B or the oversized stud kit + machine work.

So yes, you can build a 20B from 13B parts, but it will cost more than if you started out with a bad 20B core.

If you're on a budget, just build up your 13B-REW. The 20B is a great engine, but you can get similar performance from your REW in a "street" setting. I'm running damn near 500 rwhp on mine with 23 psi on pump gas and meth, and the car is on the verge of being unstreetable at that power level. And I'm on my 2nd rear end...you start breaking driveline parts north of 450. So with a 20B it gets expensive real quick and you can't even use the power on the street.

[gez]

Hi it's an r2,was thinking of a street ported na engine to get rid of the heat issues,the reason for modifying the original engine was the availability of the 20b as i live in south wales uk and rx7s are mega rare.
thanx gez

[KaosMan]

Hi it's an r2,was thinking of a street ported na engine to get rid of the heat issues,the reason for modifying the original engine was the availability of the 20b as i live in south wales uk and rx7s are mega rare.
thanx gez

If you can find 20Bs in the UK then go that route. It will cost less doing that then trying to build your original engine into a 20B.

In regards to cooling, there are ways to get the engine temps down with the stock engine. I live in Palm Springs, California - where summer temps hit 115+ F - so cooling has been a priority with me. I'm running a Turbonetics T-66 single and a Rotary Extreme monster V-mount setup, with a two-pass Koyo radiator. On the freeway at 75 mph I see no more than 85 degrees C in summer weather. Under boost & track conditions its stable at 95 degrees C, and that was before the methanol. With methanol injection it will come down further.

[gez]

Thanx for your reply and info i think i will look for a 20b in the uk if anyone has read these links in the uk and knows for a 20b could they let me know.
thanx gez