KA transmission on SR motor?? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

stillen · 10-12-2009, 08:00 AM

Hi everybody. I need a few opinions before I do this. I am having trouble with my SR transmission but I can't find a replacement. My SR tranny is loud in the range of 2500-3100rpm mainly in 4th gear, I have to depress the clutch for 2 seconds before I can put it into first or I will break my hand by grinding the gear. It sometimes sticks into gear. This happened with both my exedy and spec clutch, so I doubt it's a clutch problem. There are plenty of KA transmissions. I checked the gear ratios between, the KA is slightly higher except in 2nd gear (sources are from the internet). These are the gear ratios:
KA24 SR20
1st 3.321 3.214
2nd 1.902 1.925
3rd 1.308 1.302
4th 1.000 1.000
5th 0.759 0.752
Final 4.083 3.369

For those who have experienced this kind of combo of KA transmission on SR motor can you please answer these questions:
1. Which one do you like the SR20trans/S20motor combo or the KAtrans/SR20motor?
2.Do you notice a slower acceleration with the KA transmission?
3.Do you notice that you are at faster speeds with lower RPM's on KA trans than the SR trans?
4. Is shifting smoother, the same or worse?
5.Anything you hate or love about this kind of swap?

All opinions are greatly appreciated. Thank you all.

clark · 10-12-2009, 08:28 AM

Quote:

Originally Posted by stillen

Hi everybody. I need a few opinions before I do this. I am having trouble with my SR transmission but I can't find a replacement. My SR tranny is loud in the range of 2500-3100rpm mainly in 4th gear, I have to depress the clutch for 2 seconds before I can put it into first or I will break my hand by grinding the gear. It sometimes sticks into gear. This happened with both my exedy and spec clutch, so I doubt it's a clutch problem. There are plenty of KA transmissions. I checked the gear ratios between, the KA is slightly higher except in 2nd gear (sources are from the internet). These are the gear ratios:
KA24 SR20
1st 3.321 3.214
2nd 1.902 1.925
3rd 1.308 1.302
4th 1.000 1.000
5th 0.759 0.752
Final 4.083 3.369

For those who have experienced this kind of combo of KA transmission on SR motor can you please answer these questions:
1. Which one do you like the SR20trans/S20motor combo or the KAtrans/SR20motor?
2.Do you notice a slower acceleration with the KA transmission?
3.Do you notice that you are at faster speeds with lower RPM's on KA trans than the SR trans?
4. Is shifting smoother, the same or worse?
5.Anything you hate or love about this kind of swap?

All opinions are greatly appreciated. Thank you all.

i'm not saying i'm right, but i understood that KA and SR transmissions were the same except fr the bell housings were different.

it's funny, i have the same problem in 4th gear at similar RPMs and have been slowly realizing it may be my tranny (i've been blaming my diff)

how did you come to the conclusion it was your tranny though??

have you changed your pilot bushing? what kind of drive shaft you have? stock or aftermarket?

stillen · 10-12-2009, 04:03 PM

I have a stock drive shaft. I don't know about the pilot bushing but my transmission grinds when you put it in first gear. I don't think it is the differential because the noise comes from the front/center of the car, no t from the rear. I thought of the differential but I'm sure it's not. I didn't change the pilot bushing. Tell me if you go through with changing the pilot bushing and if it does something.Thanks

*fliprayzin240sx* · 10-13-2009, 07:07 AM

Swap bellhousings and use the KA tranny...

JDM_s14 · 10-13-2009, 08:15 AM

Quote:

Originally Posted by fliprayzin240sx

Swap bellhousings and use the KA tranny...

That's what I did. Works fine now and save me money.

SochBAT · 10-13-2009, 09:43 AM

Might not matter, but I had an SR tranny on my KA.

The trannies are geared to each motor's powerband. The SR tranny, to me, burnt more gas without being more effective at accelerating at lowerspeeds, but highend RPMs were good. It was rare that I'd let the RPMs get that high though.

KA tranny accels faster from 0-4000 RPM, but kinda goes to shit from there. Boosting isn't as fun, but shit, you shouldn't be boosting that damn high when you DD.

johngriff · 10-13-2009, 10:09 AM

I like the ka trans on a lower hp SR, makes for a better drive, more tq in 2nd' and 3rd, easier to power over in drifts (IMO).

As far as diagnosing the trans problem. Is it difficult to put it through the gears with the engine off? If so it is probably the synchro in the trans, and its time to replace.

If its easy to put it through the gears with the engine off, then its something in the clutch system.

Air in line
Slave cylinder
master cylinder
too short of a throw out bearing carrier
backwards throw out bearing

Take it to a different mechanic than your regular and have them asses the clutch situation if the second option sounds more like you. You are not getting enough throw on the clutch assembly, and the input on the trans is still spinning after you depress the pedal.

john

S13 curtis · 10-16-2009, 03:22 AM

ka tranny has shorter gears

10-12-2009, 08:00 AM	#1
stillen Leaky Injector Join Date: Dec 2006 Location: USA Posts: 60 Trader Rating: (0) Feedback Score: 0 reviews	KA transmission on SR motor?? Hi everybody. I need a few opinions before I do this. I am having trouble with my SR transmission but I can't find a replacement. My SR tranny is loud in the range of 2500-3100rpm mainly in 4th gear, I have to depress the clutch for 2 seconds before I can put it into first or I will break my hand by grinding the gear. It sometimes sticks into gear. This happened with both my exedy and spec clutch, so I doubt it's a clutch problem. There are plenty of KA transmissions. I checked the gear ratios between, the KA is slightly higher except in 2nd gear (sources are from the internet). These are the gear ratios: KA24 SR20 1st 3.321 3.214 2nd 1.902 1.925 3rd 1.308 1.302 4th 1.000 1.000 5th 0.759 0.752 Final 4.083 3.369 For those who have experienced this kind of combo of KA transmission on SR motor can you please answer these questions: 1. Which one do you like the SR20trans/S20motor combo or the KAtrans/SR20motor? 2.Do you notice a slower acceleration with the KA transmission? 3.Do you notice that you are at faster speeds with lower RPM's on KA trans than the SR trans? 4. Is shifting smoother, the same or worse? 5.Anything you hate or love about this kind of swap? All opinions are greatly appreciated. Thank you all.

10-13-2009, 07:07 AM	#4
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Swap bellhousings and use the KA tranny... __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

10-13-2009, 10:09 AM	#7
johngriff Post Whore! Join Date: Jun 2004 Location: Long Beach, CA Posts: 4,103 Trader Rating: (4) Rides Gallery: johngriff Feedback Score: 4 reviews	I like the ka trans on a lower hp SR, makes for a better drive, more tq in 2nd' and 3rd, easier to power over in drifts (IMO). As far as diagnosing the trans problem. Is it difficult to put it through the gears with the engine off? If so it is probably the synchro in the trans, and its time to replace. If its easy to put it through the gears with the engine off, then its something in the clutch system. Air in line Slave cylinder master cylinder too short of a throw out bearing carrier backwards throw out bearing Take it to a different mechanic than your regular and have them asses the clutch situation if the second option sounds more like you. You are not getting enough throw on the clutch assembly, and the input on the trans is still spinning after you depress the pedal. john __________________ [email protected]

10-12-2009, 04:03 PM	#3
stillen Leaky Injector Join Date: Dec 2006 Location: USA Posts: 60 Trader Rating: (0) Feedback Score: 0 reviews	I have a stock drive shaft. I don't know about the pilot bushing but my transmission grinds when you put it in first gear. I don't think it is the differential because the noise comes from the front/center of the car, no t from the rear. I thought of the differential but I'm sure it's not. I didn't change the pilot bushing. Tell me if you go through with changing the pilot bushing and if it does something.Thanks

10-13-2009, 09:43 AM	#6
SochBAT Post Whore! Join Date: Dec 2004 Location: Abilene, TX Age: 39 Posts: 6,428 Trader Rating: (9) Rides Gallery: SochBAT Feedback Score: 9 reviews	Might not matter, but I had an SR tranny on my KA. The trannies are geared to each motor's powerband. The SR tranny, to me, burnt more gas without being more effective at accelerating at lowerspeeds, but highend RPMs were good. It was rare that I'd let the RPMs get that high though. KA tranny accels faster from 0-4000 RPM, but kinda goes to shit from there. Boosting isn't as fun, but shit, you shouldn't be boosting that damn high when you DD.

10-16-2009, 03:22 AM	#8
S13 curtis Zilvia Addict Join Date: Jun 2008 Location: Orlando,FL Age: 34 Posts: 651 Trader Rating: (13) Feedback Score: 13 reviews	ka tranny has shorter gears