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Discussion Starter · #1 ·
Hello,

I have an 87 SR5 RWD with a 4AC in it. I also have a 96 20v Blacktop 4AGE with transmission, ECU, Wiring harness.

Is it to my understanding that this 4AGE will (with modification to the firewall) bolt up to the existing AE86 SR5 transmission that the 4AC was attached to?
Some websites say it will not and that I need a GTS bellhousing, others say that it will bolt up perfectly fine without modification.

Thanks,
David
 

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Discussion Starter · #2 ·
Update:
After sifting through forums and write-ups online I have come to the conclusion that the GTS Bellhousing is necessary to bolt up the SR5 T50 transmission to the 20v Blacktop engine block.

New question:
Using the T50 transmission and rear end from the SR5, how can I accurately record speedometer reading using the cluster that the 20v Blacktop ECU is made for? Should I:

A. Use new cluster that accomodates 20v Blacktop ECU
B. Install Autometer gauges and discard cluster
C. Use AE86 GTS cluster and hope the 20v ECU will plug in
 

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Rotary guy...
89 RX-7 Turbo
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the speedo is driven by a cable from the transmission. It'll display fine.

and I'm pretty sure you don't need the bellhousing from a GTS, but I could be wrong. I think all 4A engines have the same pattern.
 

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Discussion Starter · #4 · (Edited)
the speedo is driven by a cable from the transmission. It'll display fine.
Not sure how that answer's my question though...
The cable itself is not the culprit of inaccurate speedometer readings when using an SR5 rear end with a 4AGE motor.

However, I do see that you dropped a 4AGE into an 89 SR5. Did you need a GTS bellhousing?
 

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The speedometer will read fine on your cluster because the cable will be the same. However, if you are using an SR5 tranny with a GTS bell housing, be sure to swap the plastic gear inside the trans for the GTS speedo gear, otherwise it will read incorrectly, or break.
 

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Corolla 2000 LE
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The speedometer will read fine on your cluster because the cable will be the same. However, if you are using an SR5 tranny with a GTS bell housing, be sure to swap the plastic gear inside the trans for the GTS speedo gear, otherwise it will read incorrectly, or break.
That is completely incorrect... the speed gear (onto which the speedo cable attaches on the transmission) is on the rear end of the transmission... it is driven by a gear wraped around the output shaft of the transmission... you only need to change it if you change your differential ration, since it is made to indicate the speed of the wheel in relation to the speed of the driveshaft (which spins at the same speed as the transmission output shaft regardless of the gear selected). The engine has nothing to do with the speedometer in your cluster, since the cable is connected to the transmission and you are keeping your transmission.

As for the bellhousing, the bolt patern is the same between the sr5 (4ac) and gts (4age) but the sr5 as the starter on the passenger side in order to clear the exaust manifold (which sits lower because the intake manifold sits on top of it "non-crossflow head") but the GTS has places to bolt the starter on the driver's side under the exhaust manifold. I really do think that you can mount your starter on the intake side of the engine (passenger side) like your current bellhousing design... I don't see why you could not...
 

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I was under the impression that you were going to swap out the rear end for the GTS rear end. If you are still using the SR-5 rearend, I suppose you'll be fine with the speedo. You do, however, need to swap the bellhousing. This conversion has been done many times, and it is impossible to use an SR-5 bellhousing.
 

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Well in fwd application, the starter is on the intake side, since the blacktop exhaust interfer with it, it is a problem with mr2 (aw11) owners who have the old c50 tranny, since their is no provision to bolt the starter on the intake side while the c52 has... I'd like to see an example of someone trying to bolt the sr5 bellhousing to the 4age and failed... the only problem I could see with using the sr5 bellhousing, is that since the starter is on the passenger side, the clutch fork is actuated on the driver side and might be too close to the exhaust so you would have to shield it (and the slave cylinder) with a custom made heat guard in order for it not to burn due to close proximity with the exhaust. But the exhaust on the sr5 already passes close by, so I guess it won't be much of a problem...
I have read numerous post that tells you to get a gts bellhousing, but none where saying I tried and I failed because it doesn't bolt up, just that the stock 4age rwd exhaust hit the slave cylinder...

ince you don't have a stock manifold for the 4age rwd, you will have to locate one and the cast manifold sucks anyways. So instead of buying a gts exhaust manifold, a gts bellhousing, change the starter wiring to the other side, extend your clutch line to the other side... which will cost some money, invest it in a custom tubular exhaust manifold that follows your stock exhaust routing (away from the slave cylinder), you'll get more performance out of it and will end up costing you about the same and saving you a lot of headache with the other stuff... just my 2 cents...

Have a look a those picture of a 4age tubular header http://forums.club4ag.com/zerothread?id=6239 scroll down to a little below the middle of the page where he shows the steering rack and you'll see the space between the bellhousing and the exhaust (this is a gts bellhousing and you can barely see the stater at the top) the clutch slave cylinder on a sr5 would be situated a little below... which in my mind leaves lot of space to put a heat shield between it and the exhaust...

Here is an example of a 20v in an older corolla but with the slave cylinder on the exhaust side... http://www.rollaclub.com/board/topic/29506-20-valve-into-ae71ae86ke70/

oh and for the record, the gears ratio for the sr5 is the same as the gt-s one, and the same as the 2t-c, 3t-c, etc... the bearings are also the same between all the t50 bolted on a 4a engine (not the same as the early 2t though) so it is not any weaker or stronger thant the gt-s one.

The rear (differential and axle carrier) is a little weaker (according to everyone), but uses the same axle as the early gt-s... the crownwheel diameter is 8mm smaller, but since you have a 4 pinion carrier (instead of the 2 pinion the gt-s has) my bet is the strength difference must not be very big... and since you have a 3.909 rear ration (instead of the 4.300 for the gts) you will put less strain on the axles (torque applied on the axles is multiplied by the same factor as the reduction between the pinion and the crownwheel) less steep = less torque to kill your axles splines. For LSD option, you are pretty much fucked but that is all...
 
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