Honda CRX Forum banner
1 - 20 of 21 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Looking to pickup an 89 CRX Si.

wanted to make it a fun daily with fuel economy at the fore, but HP gains over stock.

plan was to use a motor from a 95 EX, but not sure what to do about tranny.


in the EX coupe, the 132HP would yield 37-45MPG.

I assume gains from the lighter cRX chassis, and I assume that it will also have better acceleration than my 160HP 2700 lb 02 RSX base.

if there are any glaring problems with transmission compatibility, or any tips on what else I would need to upgrade with this motor swap, please let me know.

would upgrade suspension over time, but don’t think I would need to upgrade brakes.

If I could build something with 50MPG and that power to weight ratio, I think I would keep it for 10 plus years and cover the build costs in gas savings alone.
 

·
Registered
Joined
·
20,350 Posts
plan was to use a motor from a 95 EX, but not sure what to do about tranny.


in the EX coupe, the 132HP would yield 37-45MPG.
I highly doubt you're going to see 132hp from that motor, it wasn't even rated that much from the factory.
Realistically, you may see 110 or so from that d16z6 motor.
As for transmissions, you can use any d series Civic transmission from 88-2000.
 

·
Registered
Joined
·
2,977 Posts
Mr. Wikipedia says 127 HP from the D16 in the 95 EX. It's still a D-series, so the regular transmission from the CRX should be able to work on it, though you may need to do some careful mix-and-match with clutch and flywheel parts. Alternately, you should be able to fit the trans from the later car into the CRX, but you will need a cable-to-hydraulic clutch conversion, possibly some fiddling with the axles, and likely something to get the speed signal into the speedometer and engine management.

The EPA rated the Ex at 29/35 MPG (city/highway), while the stock mid-range 1990 CRX (the "DX" with a manual trans) was rated at 27/33. Your numbers seem optimistic, though EPA can definitely be exceeded by careful driving. I would expect typical MPG numbers (assuming normal driving) for the 95 motor in the CRX body to be between those figures. There wasn't an immense amount of new tech that went into the engines in those 5 years.

That said, the gearing of the trans has a pretty strong effect on MPG and acceleration. The more-sporty CRX Si had a 1.6 liter (as opposed to 1.5 liter) and low gearing, making 108 HP and EPA 24/30 MPG, while the HF had much taller gearing (and other low-drag stuff) and made 40/47 MPG.

It will be a project. If you start with a DX shell, you'll have to do some re-wiring to accommodate the MPFI of the later motor. Si and HF shells are already MPFI, but there will be work to get the engine management to play nicely. It should be fun when it's done, though!

One suggestion I have to start with: Try the CRX in bone-stock condition if you can. It's pretty enjoyable in that form, and the economy is at least decent!

--DD
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #4 ·
I will try it stock. The civic ex from 95 got 35 city and over 40 on highway over the decade I had it, and I was thinking the extra 20 horses and the lighter weight would be amazing in the CRX. Thank you!
 

·
Registered
Joined
·
15 Posts
i would honestly stay away from doing that... not enough on the gain and horsepower usually just means how FAST you can go... torque is where you will get better mileage honestly... I drive a 91 HF with a b20b in it, bottom end from a crv so a little more torquey than the normal and I get between 25-40 based on how i drive(mostly 25 though lol)
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #6 ·
This is probably best to death in other threads, but I’m not sure how to form good questions to lookup best solutions.

if I start with a bone stock 89 si with a blown tranny, what is the most cost effective order of operations to get it running as a daily, and then build up the engine to 130-160 hp over the longterm?

Priority is daily reliability first, then improving it as a weekend backroad summer corner carving driver long term.

I like the idea of trying the engine in stock form, but if I need to have transmission and possibly clutch work done, what is the most cost effective upgrade to:

a) make sure whatever transmission work need done that it guarantees both current performance improvements and future compatibility with a possible engine swap

b) and what are some of the best b series swap choices for long term (again, knowing that the most HP I would need would be @160 but that I would be ok going from stock to 130 and then another bump to 160).

c) is it possible to have the engine rebuilt to produce @130 or is it smarter to save that money to invest in an engine swap capable of exceeding that?

I am looking at NA only / no turbo solutions for long term engine work, and don’t mind spending 1500-2000 up front on the clutch/transmission parts and labor. Looking to spend a few thousand a year until it’s fully sorted. I will have a daily in the meantime, so I can afford a few weeks downtime per year for upgrades.

And unlike most of the examples I have seen locally, I don’t want a race car, but want something balanced (performance equivalent to a retro version of a RSX type s but with much better MPG).

The question is, can I have both the mpg and the fun?
 

·
Registered
Joined
·
15 Posts
as i did that with my CRX I have a B20b that is rated at about 150ish HP and 140ish TQ with nothing done to it... so i am proly getting about 130-140hp at the wheel with everything. B20,B18 and B16 are the engines you wanna look at for B series... honestly any as well but the B20b is best for the B20... and as i said, i get 25-40 mpg based on how i drive... either i wreck others, or i drive like a normal person lol I also dont wanna go the turbo route and am planning on putting on this B16 head to get VTEC and building top and bottom end.
 

·
Registered
Joined
·
2,977 Posts
I don't have good answers, but I'll chime in with a few caveats:

  • The D-series transmission is not compatible with the B-series engine nor vice-versa. If you are going with a B, that means both the engine and the transmission.
  • Swaps get complicated in areas with significant smog laws. I am most familiar with the laws in California, where you cannot swap a truck engine into a car (that means most B20 engines) and any swap you do has to have the equipment and meet the emissions specs of the later of the engine or chassis. Check your local laws to see what is required where you live. And keep in mind that many of these laws also apply to vehicles brought in from out of state, so if (for instance) you want to move to CA then you should check out the laws there.

--DD
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #9 ·
Thanks for the feedback on D vs B series. Luckily, maine does not have emissions testing or smog laws, so I wouldn’t rule out a future B swap.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #11 ·
I have an RSX I can daily until the CRX is fully sorted.

if the CRX transmission is truly shot, I’ll need to put together a parts list.

from what I’ve read, one of the B18B series engines would be an ideal swap to hit my moderate 130-140 HP goals. I’ve also read that the transmissions from the integra LS series are an ideal swap if going with these engines.


In addition to motor and trans, I assume I will have to replace:

ECU
How much electrical will need to be replaced?

Fuel pump?

but what else?

Will that motor bolt up to the existing AC? As a summer daily, AC is a requirement.
 

·
Registered
Joined
·
1,764 Posts
If it was me I would just get another D series transmission, Si will give better response but will keep rpms higher at hgwy speeds hurting mpgs.

I would build a higher compression D16.
Either way you will need to tune, and 1.6 engine means higher mpgs but still fun to drive.
If you are looking for lots more performance then go with a swap but you will need lots of parts more, its not just putting another engine and transm and thats it, depending on what you pick some swap may even leave you spending more $ just to be able to have AC.

I'm not up to date on B or K swaps but from what I remember, engine and transm mounts, shift linkage, wiring,ecu, exhaust system mods.
I cant recall but there was some beating up on the chassis to fit the alternator on its original position.
im sure there is more to it.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #13 ·
If it was me I would just get another D series transmission, Si will give better response but will keep rpms higher at hgwy speeds hurting mpgs.

I would build a higher compression D16.
Either way you will need to tune, and 1.6 engine means higher mpgs but still fun to drive.
If you are looking for lots more performance then go with a swap but you will need lots of parts more, its not just putting another engine and transm and thats it, depending on what you pick some swap may even leave you spending more $ just to be able to have AC.

I'm not up to date on B or K swaps but from what I remember, engine and transm mounts, shift linkage, wiring,ecu, exhaust system mods.
I cant recall but there was some beating up on the chassis to fit the alternator on its original position.
im sure there is more to it.
Really appreciate this perspective. This community is great.
 

·
Registered
Joined
·
20,350 Posts
There is a bunch of info here that would help you out...

 

·
Registered
Joined
·
684 Posts
i would honestly stay away from doing that... not enough on the gain and horsepower usually just means how FAST you can go... torque is where you will get better mileage honestly... I drive a 91 HF with a b20b in it, bottom end from a crv so a little more torquey than the normal and I get between 25-40 based on how i drive(mostly 25 though lol)
Agreed. K-swapped 6-speed CRX I was getting 40ish mixed mileage with the OEM RSX type-S gearbox. Take off in second, shift to fourth, and basically idle around town in sixth. Car stayed in sixth gear the majority of the time I drove it.
 

·
Registered
Joined
·
684 Posts
I have an RSX I can daily until the CRX is fully sorted.

if the CRX transmission is truly shot, I’ll need to put together a parts list.

from what I’ve read, one of the B18B series engines would be an ideal swap to hit my moderate 130-140 HP goals. I’ve also read that the transmissions from the integra LS series are an ideal swap if going with these engines.


In addition to motor and trans, I assume I will have to replace:

ECU
How much electrical will need to be replaced?

Fuel pump?

but what else?

Will that motor bolt up to the existing AC? As a summer daily, AC is a requirement.
Do a cheap B-series swap. B20 if possible, and whatever transmission you want. Stock fuel pump is probably fine. Get a Hondata S300, you can't trust the capicitors on these old boards, and they use new caps. You're going to maybe need axles and shifter linkage between the stick and transmission (I've only done K-swaps, they're cable). Also hydro vs cable for the transmission in most cases.
I wouldn't bother with retaining the D-series. You can buy universal AC kits for like $500 so long as you have a compressor. Sell the D-series and spend a few grand getting it swapped, it will be worth it in the long run if you want the extra power and better mileage.
 

·
Registered
Joined
·
1,764 Posts
You need to decide how much $$ you are willing to invest in the car.
Then go from there.
 
  • Like
Reactions: Baker

·
Registered
Joined
·
1,764 Posts
Realistically.
^ 100%. Operative word.
(y)

I knew i was missing something. Lol
Tks Baker
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #20 ·
I’d probably have about $3,000 to throw at it in the first year (transmission, possible electrical) and then another $3,000 next year.

Wouldn’t want to dump more than that into it, because then it’s getting close to what purchasing one that’s already been sorted would look like.
 
1 - 20 of 21 Posts
Top