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f23 how good are they?

20K views 35 replies 12 participants last post by  M/PORT 
#1 ·
what sort of power can they take?

how smoothe is the gear change?

can you get lsd for them?

are they parts avalible to fix them if they break?

think i may have had on in my vectra 2.6 v6 but not too sure

cheers peeps
 
#4 ·
1st to 2nd can get notchy. but very slick in all other gears (and them if they arent fooked)

Parts from GM are twatting expensive, but with so so so many F23's about you can easily get a few for spares.

power wise, the yanks are pushing LOTS of power/torque through them with the LSJ/L61/LNF etc
 
#5 ·
deek
what sort of power can they take?
not power- torque!
it has bigger gears then f16/18/20, i think size looks like f28.
how smoothe is the gear change?
it's better, because it has gearshift with cables. it's better with stock soft engine mounts.
can you get lsd for them?
Vauxhall Astra F23 Quaife ATB Helical LSD differential - Quaife Engineering
are they parts avalible to fix them if they break?
yes, but not cheap. may be you can find some aftermarket parts.
may be saab use that box?
think i may have had on in my vectra 2.6 v6 but not too sure
yes, vectra B v6 have this box
 
#8 ·
On the astra's 3rd can be abit hard due to engine movement causing the cables to flex, But its a easy fix by fitting the front engine/gearbox powerflex bush which costs around £20.

I dont know if this applys to the vectra tho ?
 
#9 ·
im also looking into this for my corsa let. doesn't seem to be much info around after searching the net though. astra owners club seems to have the best info on the f23. obviously the z20let mk4 gsi boys.
 
#10 ·
There is two setup you can use to fit the f23 to the c20let/xe

You can use the whole (C20LET) flywheel and clutch setup, But they use the pot type fly and is heavyer than the flat type (pot 9.6kgs, flat 6.5kgs)
OR
You can use the xe early flat type fly, You'll need the c20xe pressure plate to match the flat type flywheel, But you have to use the Calibra turbo(c20let/f28 box) friction disc to match the input shaft from the f23 gearbox (The f23 and f28 have the same number of splines).
 
#11 ·
cheers m/port but i was struggling more on which f23 to go for but turbo chris has just said the f23 from the z20let has different ratios. i suspect that it would be better suited than an f23 from an N/A car:rolleyes:lmao

one more question for you though (sorry deek). i know the 23 has a different amount of splines to the f20 so ill have to change the shaft right? if yes then will the astra one be suitable length for the corsa and my hubs?
sorry if there dim questions but im not really up on transmission/chassis.
 
#12 ·
one more question for you though (sorry deek). i know the 23 has a different amount of splines to the f20 so ill have to change the shaft right? if yes then will the astra one be suitable length for the corsa and my hubs?
sorry if there dim questions but im not really up on transmission/chassis.
Which splines do you mean ? Drive shaft inners or outer cv's ?

All astra mk4 (G) driveshafts use bigblock hubs (outer cv's 33 splines) no matter the engine size/gearbox, Which are the same as f20 outer's.

The f20 inner splines are 34 and the f23 inner splines are also 34, So they will also fit the f23 gearbox.

I dont know about the shaft lenghts but ill have alook now
 
#13 ·
i've used F23's on let conversions and using one now on my z20let conversion.

Jim on vvoc had one running 400lbft with a quaife and never had no problems. Chip also has one in his nova along with klasen in there 600bhp vx220 so there proven.


Also they are10 a penny in F23 guise but there about 20 different versions of the same box (i.e vectra's mount differnt to astras, diesels, v6's, 2.2, 2.0's all have differences then there different ratios also) so easy to get hold of


F23's are the future imo
 
#14 · (Edited)
Here you go fromtheearth the difference between the astra f23 and you orignal corsa shafts.

All the measurements are the Compressed lenght of the driveshafts.
astra mk4 left handside f23 shaft is = 595 mm.
astra mk4 right handside f23 shaft is = 957 mm.
corsa left handside shafts are = 565 mm.
corsa right handside shafts are = 915 mm.



But it depends on what car the f20 driveshafts are off as some are different ie astra mk2 gte, mk3 gsi, cavalier, calibra ect.
gte left handside f20 shaft is = 610 mm.
gte right handside f20 shaft is = 946 mm.
cavalier left handside f20 shaft is = 595 mm.
cavalier right handside f20 shaft is = 940 mm.
calibra left handside f20 shaft is = 595 mm.
calibra right handside f20 shaft is = 940 mm.

If your using any different ones to what ive listed give me a pm and ill get the measurements for you.
 
#15 ·
cheers M/PORT great info:beer:

lee wouldn't it be better to source a f23 from a z20let rather than from a N/A car? im worried that an f23 from a non turbo motor will have a **** top speed and wont be as strong:confused: trouble is i cant find one from a z20let on egay:(
 
#19 ·
so you will get a better top speed out of the zlet boxes and have to thrash it less on motorway journeys. ill keep an eye out for one of those then, even though i wouldn't know how to differentiate one from any other f23:rolleyes:
 
#20 ·
If you want a wr box get the f23 from a diesel.

I have searched high and low to find out if you i could get a cr f23 and fit the 5th gear from a wr f23, Just like you can with the f18 wr 5th in the f20, But nothing came up :(
 
#21 ·
i wonder if the z20let f23 are cr with a wr 5th:confused:

turbo chris said the turbo boxes had a different ratio to the N/A boxes.

also got told to make sure the box was from a petrol model.:confused:

sod it! all is forgiven f28lmaolmaolmao
 
#25 ·
also got told to make sure the box was from a petrol model.:confused:

sod it! all is forgiven f28lmaolmaolmao
You can use petrol and diesel ones apart from the f23 that comes on 2.2 as the cut out on the bell housing of the starter motor is in the wrong place.

And the vectra f23 mounts different to the astra one
 
#23 ·
just to confuse things further..... I read somewhere that the Zafira ZLET F23 is geared shorter than the Astra ZLET F23. So maybe the X20XEV and Zafira ZLET have the same ratios?

Also not all Astra G X20XEV's have the F23, earlier models have the F18.
 
#26 ·
Vectra


Code:
1 TRANSMISSION,ASSY.,4.17 RATIO 16LZ2,20NEJ,C20SEL, 1 90578385 7 00 032
(IDENT SQ) X20XEV
90578385

1 TRANSMISSION,ASSY.,3.74 RATIO C20SEL,X20XEV,C22SEL 1 90578390 7 00 037
(IDENT SR)
90578390

1 TRANSMISSION,ASSY.,3.95 RATIO C20SEL,X20XEV 1 90578386 7 00 033
(IDENT SS)
90578386

1 TRANSMISSION,ASSY.,3.74 RATIO C20SEL,X20XEV, YL000001 - 1 90578390 7 00 037
(IDENT SR) (FOR VEHICLES WITH C22SEL
PLANT CODE L)
90578390

1 TRANSMISSION,ASSY.,3.95 RATIO Z22SE 1 90578392 7 00 092
(IDENT ST)
90578392

1 TRANSMISSION,ASSY.,3.84 RATIO X25XE,Y26SE 1 90578391 7 00 038
(IDENT SK)
90578391

1 TRANSMISSION,ASSY.,3.84 RATIO X20DTL,X20DTH,Y20DTH 1 90578387 7 00 034
(IDENT SL)
90578387

1 TRANSMISSION,ASSY.,3.95 RATIO X20DTL 1 90578388 7 00 035
(IDENT SM)
90578388

1 TRANSMISSION,ASSY.,3.74 RATIO X20DTH,Y20DTH 1 90578389 7 00 036
(IDENT SP)
90578389


Astra G

Code:
1 TRANSMISSION,ASSY.,3.95 RATIO X20XEV 1 90578397 7 00 051
(IDENT SC) (EXCEPT OPC) (ALSO
USE 90470781 7 24 632)
90578397

2 TRANSMISSION,ASSY.,3.95 RATIO X20XER 1 24426557 7 00 090
(IDENT TS) (FOR OPC) (ALSO
USE 90470781 7 24 632)
24426557

3 TRANSMISSION,ASSY.,3.74 RATIO X20XEV 1 90578400 7 00 052
(IDENT SH) (ALSO USE 90470781
7 24 632)
90578400

4 TRANSMISSION,ASSY.,4.17 RATIO X20XEV 5 DOOR HATCH 1 9126007 7 00 088
(IDENT SD) (FOR SOUTH AFRICA) F48
(ALSO USE 90470781
7 24 632)
9126007

5 TRANSMISSION,ASSY.,3.63 RATIO Z20LET COUPE F07 1 90424091 7 00 091
(IDENT TR)
90424091

5 TRANSMISSION,ASSY.,3.63 RATIO Z20LET COUPE F07 1 (90424091) ( 7 00 091)
(IDENT TR) (NLS.- USE
24451449 7 00 220 AND
SUPPLY 90470781 7 24 632)
(90424091 )
 
#30 ·
do the ones from a v6 have a longer bellhousing like the f25 did?

is the gear change nicer then a f28?

im just undecided on what box to use,i have a f28 with a diff that i rebuilt and has done no more then 2k since,but i dont like the gera change to much,i have a saab gearbox in my van which i like but they brake with high power, but i have all the bits needed to rebuild them and have rebuild loads so could be athe best option,as u cant get bits for f28,then there is the f23 cable so id geuss better smother gearchange but modding needed to get in my van then if it breaks will need modding again to fit another box.

both the f23 and saab box need diffs and require me to sell my f28 to get a diff for them,which is why im struggeling to decide which is the best option,if all goes to plan i should have in the region of 500lbft of tourqe and dont want a box that will break within 5 mins
 
#31 ·
you will always struggle with any fwd box that to ask it to cope with 500ft lbs thats a massive amount of torque, depends how its used but you would kill any 3 of the above mentioned boxes i d say just keep a few spare boxes lying around :)
 
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