Thinking about a transmission swap - need input

[Ecky]

Hi all! It's been a while since I've been active here, but I haven't stopped tinkering.

In my Del Sol I have a B18B engine (a bit of a frankenstein really) paired with the very short (manual) transmission from a B16A. In 5th gear, 2500rpm = 45mph, and 65mph = 3600rpm. I've been playing with the idea of picking up a taller transmission but to my knowledge, the tallest transmission available for a B-series motor will bring me down to about 3000rpm at 65mph.

First problem: I have no experience with taking out or installing a new transmission. I'm not afraid to try, but it's a little daunting to go into it without assistance.

Second problem: having the shorter B16 transmission generally improves the value of the car. I've been toying with the idea of selling the Del Sol and picking up a used first-gen Insight or if I can find one (unlikely), an unmolested CRX HF. I probably won't have the cash needed to pay the difference for an Insight for at least a year or two though as I'm a poor college student.

The transmission swap is economically feasible because the B16 transmission is worth considerably more than the transmission I'd be replacing it with and I might even walk away with some more cash in-pocket if I can do the labor myself.

I guess I'm looking for some feedback, some "what would you do", if you will.


Some other thoughts:

With the weather getting a little cooler here in Florida, my fuel economy has actually improved. Cruising at 25-45mph I was getting in the area 42-48mpg. With the weather a little cooler (90F -> 60F) I'm now in the range of 45-60mpg. I've had trips across town (with traffic lights) where I've been just shy of averaging 45mpg. It's definitely the weather, as I saw an immediate change after the first cold front came through. Why might cooler weather have this effect?

Also, I was reading the thread concerning smaller throttle bodies and it got me thinking - I'm using the TB from my old B16A on the B18B intake manifold. Because it's such a large bore (the B16 was a higher performance motor), it takes very little pedal to get 0% vacuum. My question is: does the ECU learn and adjust the enrichment points, or does having a large TB allow me to run higher vacuum without hitting fuel enrichment? Are there any downsides to this?

Thanks all!

[nbleak21]

In regards to the TB, yes, your exu will adjust for the larger TB, via o2 sensor, but generally allows you to run slightly leaner due to the TPS offset.

I will likely be doing the same with my F22 Acura. I doubt you'll have any negative effect running the b16 TB.

[brucepick]

Maybe this is only semantics, but...
I think you want a taller transmission, not shorter. To get lower RPMs at any given road speed.

I think the tallest B series trannies would be from a VX, CX or DX. And ask around in tuner groups if you can use bigger rims with larger diameter tires on your DelSol. Keep them as skinny as you can though.

[Ecky]

Originally Posted by brucepick

Maybe this is only semantics, but...
I think you want a taller transmission, not shorter. To get lower RPMs at any given road speed.

I think the tallest B series trannies would be from a VX, CX or DX. And ask around in tuner groups if you can use bigger rims with larger diameter tires on your DelSol. Keep them as skinny as you can though.

My bad, was a typo. Fixed it.

Unfortunately the Civics by and large all use the D-series. I have no idea what is involved with mating a B series motor to a D series transmission, though I would consider it if it's not too involved.

The tallest B tranny would come from a 90's Integra GS/LS/RS. To my knowledge, there was never an economy car with a B-series motor so all transmissions are actually fairly short. The B16's is just the shortest of the lot.