1st gen CRX SI gear ratios?

[cashmo]

http://kumo.swcp.com/synth/crx/specs.html shows different gear ratios for 1985 US CRX SI's vs 86-87 cars. Can anyone confirm that these are correct?

85 = 3.30/ 1.99/ 1.35/ 1.00/ 0.79 with a 4.27 final drive
86-87 = 2.92/ 1.76/ 1.19/ 0.87/ 0.71 with a 4.40 final drive

Is there any chance that the 4.4 final drive can be used in the 1985 tranny?

Thanks,
Jeff

[ITC Racer]

While I have not disassemblied the two trans and counted teeth, I believe all gear ratios are the same from 84 to 87 within CRX Dx model. The gearing between the 85-87 CRX Si is the same as the Dx trans with the exception of the final drive gear which is a 4.4:1.

There was a difference in the 86 and 87 Si case that will allow a 4.93:1 final drive gear where the earlier cases will not.

Based on this, just pick up a complete Si trans and swap it in rather than swapping the final drive gear if you do not have to pull the case apart otherwise.

Good luck

[Knestis]

If any of the gearsets in eligible year cars are different that what is listed on the spec line for the '84-87 Si, it might be a good idea to submit a request to get them added, through "errors and omissions". The book says...

2.92/1.76/1.81/0.85/0.71

...which is different than either of those in cashmo's post. It would be a shame to get dinged because the spec line was incomplete and having all options listed would give you the greatest flexibility of replacement.

Kirk

[cashmo]

<font face="Verdana, Arial" size="2">There was a difference in the 86 and 87 Si case that will allow a 4.93:1 final drive gear where the earlier cases will not. </font>

Hmmm, I got the following from someone else...

"Yes, those numbers are correct. If you check the effective ratios between the two, you'll see that they are nearly the same. I think it's possible to swap the FD between these trannys to end up with a really short tranny, but I know that the countershaft is a little shorter on the 84-85s, so I think you have to use the case from the 86-87 along with it's FD. "

However, after figuring out the top speeds, etc. the swap between the 4.27 and 4.4 hardly seems worth it. However, the 4.93 sounds like a winner.

To be clear, the car I'm interested in is a 85 CRX SI. It sounds like I need to get a 87 CRX SI trans and find the 4.93 from somewhere, correct?

Thanks,
Jeff

[cashmo]

2.92/1.76/1.81/0.85/0.71

...which is different than either of those in cashmo's post.

Well, somethings sure wrong with the GCR. I can't imagine 3rd gear being higher than 2nd (1.81 vs 1.76). Does anyone have a 1st gen CRX SI shop manual to see what it says?

Thanks,
Jeff

[davew]

try this:

http://www.blackoutsi.com/tranny_specs.htm

dave w

[jsgprod]

These figures are right out of my '85 CRC Si factory manual.

2.92/1.764/1.181/.846/.714 F/D 4.428

I've also checked the gear count and the numbers are correct. The '85-'87s are identical as I have both. I have also disassembled and counted the gear teeth on a '86 HF box (4.06 F/D) and the tooth count is actually different but the gear ratios come up to almost (but not exactly) the same ratios as listed above! Sometimes Honda just outwierds(is that a word?) itself!

I also have a 4.93 F/D from Houseman, used three times, that I will not need in the very near future. These things aren't cheap! I do need another HF final drive though.

Jay

[Knestis]

Third gear number tranposition in the ITCS - break out the E&O eraser...

K

[cashmo]

<font face="Verdana, Arial" size="2">These figures are right out of my '85 CRC Si factory manual.</font>

Jay, is there any chance your factory manual has the valve sizes listed? Under ITA the ITCS says...

Honda CRX SI (84-87) 27.1 (I) 33.0 (E)

While under GP the PCS says...

Honda CRX SI (84-87) 27.1 (I) 32.1 (E)

Should the exhaust valve sizes be the same?

Thanks,
Jeff Cashmore

[jsgprod]

The pcs has the wrong information listed.
I still don't understand how they can have the right info in one category, IT, and get it all wrong in the same publication in the PCS listing.
All CRX Si's from '85-'87 came with 33mm exhaust valves. The carbureted cars had 32mm valves.

Jay

[ITC Racer]

Jeff- I doublechecked my Haynes manual last night (85 CRX and Si) and the ratios listed above by Jay are what is printed. The internal gear ratios (1st through 5th and reverse) are the same for 85 Dx and 85 Si trans. The only difference is the final drive- Si is like 4.4:1 and the Dx is 4.2:1.

Are you getting into CRXs from the RX7? If you have other questions on the first gen, let me know.

FYI- Midwestern Council runs the 85-87 CRX/Civic Si in ITB... They are a whole lot more competitive there.

Devin
[email protected]

[This message has been edited by ITC Racer (edited January 09, 2003).]

[cashmo]

Are you getting into CRXs from the RX7?
FYI- Midwestern Council runs the 85-87 CRX/Civic Si in ITB... They are a whole lot more competitive there.

Well, the Spec RX7 was sold after the 2000 season (got married that year). We still Solo like crazy but every year I watch the Runoff's on Speed I say to myself "I should/would/could be doing that". The original thought was to buy a 1st gen ITA CRX and convert it to LP GP. However the math is adding up to be a big money pit. $5-7k motor from King, then $6k for a Houseman gear box, $1k Quiafe, stiffer torsion bars & rear springs, stiffer shocks, fiberglass fenders & hood, lexan glass, upgrade the cage, Panasport 13x6 wheels, fire system, fuel cell, etc. It would be cheaper to buy an existing Prod car. Plus, you have to stop and haul 2000 lbs around on a LP suspension.

They just extended the Showroom Stock window to 10 years so that's another option. Neon/Mazda contingency money would be a bonus but I'd still have to have someone go through the motor to have a shot at being competetive.

Yes, plan B is to run the car in ITB with Council. At least that gets me back out on the track. However, plan C has just showed up in the guise of a SM renter that might need my help. Who knows how this will end up.

Thanks,
Jeff

[85gen1crx]

Jeff,

Check the 2002 MC results for Grattan and Gingerman...1st gen CRX Si can run and beat most 2nd CRX Si....find 4.93 & LSD combo and come and play with us.

Jason