20/20 Vision

[DeftAnesthetik]

Well the time has come and I have done all the searching and scouring of the internet for the last year. I have been brooding over what 4a conversion to choose and have made my choice. I am definately going to go with a 20 valve. The only thing is I don't know which one to choose and need some advice and some additonal info from anyone who can offer it. Please do not try to sway me away or point out that i have limited modifications with the 20 valve, I already know this. I am not going to do forced induction of ANY kind (unless you count a cold air intake system as forced induction) I am just having a few hard time telling what the real difference between the B/T and S/T motors are. I know the AFM/MAP difference, that the B/T has lighter internals and rated for an extra 3kw over the S/T from factory. Other than this can someone tell me why the B/T is DOUBLE the cost of a S/T and if it is worth it? Also I am unable to find out if I can use the same Clutch/Oil Filters as a standard 16valve. I am in Canada so JDM stuff is not exactly available on a dialy basis so if the 20v has specific consumable needs I would be ordering a few to keep on hand but if i can use the 16valve stuff then thats easy to get my hands on. Again please do not talk about "what can be done to make it fast" as this engine is replacing a 3A engine and "specs out" at nearly TRIPLE the power I already have. $700US for SilverTop or $1400US for BlackTop. Is it worth the extra cash? And if so Why, if not Why Not? Thanks in advance to all who reply

[gearb0x]

Definately a big difference in price, i would be looking at *whether* that price includes the 6 speed box which seems to bump the price up a bit on blacktops

[Big T]

Differences that i can remember off the top of my head.

1. B/T uses some sort of silicon belt tensioner that is a bitch to change
2. 42mm S/T throttles vs 45mm B/T
3. B/T uses thinner rods (bad imho seeing as the S/T are already thinner than smallports)
4. Cylinder heads are slightly different with S/T having better squish areas. (it's in Bill Sherwoods site, have a look)

Out of curiosity, will this be going into a RWD or FWD setup?

Eddie.

[DeftAnesthetik]

After reading this I realize i should have been more specific.... at any rate here is what i would like to know exactly

1) what are the rpm limits on either engine? (i have a tendancy to drive hard and redline quite a bit)

2) What style of crank do either engine have? ie forged/cast/iron/steel

3) If i do go S/T (which is very likely) Can i later swap in a MAP Harness and ECU?

I am not really interested in the transmission (although it will come with either package) So if the 6spd is what primarily contributes to the extra cost, how much demand would i see in trying to get rid of it?

Thanks again in advance. For those of you worried about the tranny i have not holding up (a BIG concern for me as the original engine is a 3A w/62HP) i found this site, according to this guy it will talk at least 182HP and 224ft/lbs of torque

http://chaosinteriors.com/project_cars.html

[DeftAnesthetik]

Thanks Big T, Bill has lots of info, probably the best collection around, I have visited MANY times to help me decide which way to go.

It is going into a FF setup but the engine will not be mounted transversly as you would expect. I have posted a few pics in the members rides section, under '81 Tercel SR5 Rebuild.

oh and from before the tranny won't "talk" it will "take"

[The Witzl]

A couple of quick points....

# The main cost difference is what we call "wank-factor".... ie "look at me, i'm cool cos i have a blacktop 20V"

# The 2nd cost difference is the gearboxes. Some blacktops had LSD centres, and the 6 speed is definitely a good box to have!

# DO NOT use your original gearbox from the 3ac - it has the completely wrong gear ratioss and you will never see the power and powerformance you should be getting if you were to use the correct C56 or 6 speed box (20V box).

# You cannot use the blacktop loom and ECU on the silvertop engine... it's a waste of time even if you could!

# The silvertop is the 20V of choice in my opinion... there just isnt a valid reason for spending on the blacktop unless you REAALLLY want the 6 speed box!

# Not 100% sure on the blacktop, but the silvertop has a forged crank, which (along with the rods) are the same as an AE101 4A-GZE.

# The RPM limits are virtually the same on both engines from memory.

[DeftAnesthetik]

I was thinking the "cool" factor was the main reason for the B/T, Where I am at (western Canada) Almost everything "cool" is either a Mopar (HEMI) or just adding the muffler to make your engine sound like your smackin ho's like your some sort of pimp (thwack, thwack, thwack) Makes me sick, my car is already one of the best off the line in these parts, just nothing in the long run. I do get quite a few looks driving it around (teenagers stare at the juice jug i modified and screwed to the hood for a cold air intake) There is a RX-7 in town that has problems pulling away from me. I have to laugh, this car of mine looks like such a piece of crap. HA HA.

Not sure what kind of options i have for replacing the transmission without alot of fabbing. If your not familiar with the car here are a couple of pics of the transmission, housing and differential. The pecular thing about this car is that it is a FF but the engine is NOT mounted transversly, it is dropped in the same as a RWD.




I will have to try with the current tranny and see how it drives, if i do need to swap the tranny i will start looking for a solution then.

All in all, my questions have been answered. I am definately going S/T the cash i save will go into the exhaust system, gaskets, and probably a set of racing seats.

Thanks Witz, i really wanted to know about the crank and if the S/T is the same as the GZE then i know it should take some abuse.

by the way the engine is not a 3A-C it is only a 3A, don't have stringent emmisions laws here in Alberta.

Thanks to all again

[Nim]

The Blacktop also has VVT-i rather than just VVT. VVT has one switchover point for intake cam timing, where VVT-i has multiple points (10 rings a bell... but I can't be sure).

So the blacktop would be harder to tune properly.

[General_Bupkiss]

from memory the b/t also has a lightened flywheel, but as stated earlier the rpm limit is pretty much the same for both engines.

[DeftAnesthetik]

Couple of quick questions to add here. I am going to need to convert over to an electrical inline fuel pump for this, what kind of flow rate should i be looking at? as in how many litres/hour should be enough and are there any suggestions on what make/model fuel pump to use?

[Garth AE86]

i have a 3SGTE pump in my car from an SW20
flows heaps and isnt loud as hell

more commonly used is an external pump from a VL calais, noisy as hell though.

if you want to buy brand new, Walbro (US company) make a 255LPH pump to fit intank for an EFi fueltank

[DeftAnesthetik]

I grabbed a pump from an AE86 off ebay for $5, looks to be in awsome shape. will this be enough for the 20v? I looked into a walbro but for the cost it is cheaper for me to drive to the wreckers (2hrs) and pull one, plus then i can get some other items too. Thanks

[oldcorollas]

the AE86 pump will work fine... although the 20V has extra valves, ti is still 1.6L and has a small fuel consumption...
maybe you need something like 60L/hr?

the small Walbros are 155L/hr at 40psi = massive overkill..

but remember that the Holley branded Walbros.... are still Walbros and much cheaper

[Quinn]

The Blacktop also has VVT-i rather than just VVT. VVT has one switchover point for intake cam timing, where VVT-i has multiple points (10 rings a bell... but I can't be sure).

So the blacktop would be harder to tune properly.

The blacktop 20v runs VVT, not VVT-i

http://www.billzilla.org/vvtvtec.htm

Bill's website has a wealth of information on all of the 4age varients.

[adamaw11]

I'm surprised no one has mentioned the blacktop having more compressions 11:1 vs 10.5:1 for the silvertop

Also, the blacktop supposedly has a little more duration or valve lift (not sure which) than the silvertop

I can confirm the blacktop has a lighter flywheel, it has cut-out sections to reduce its weight.

FWIW I changed from silvertop to blacktop this year, partly cause my silvertop was gettin a bit tired. I already had an aftermarket ecu, and just richened it a little for the blacktop
with silvertop 15.9 @ 139kmh
with blacktop 15.0 @ 148kmh
hows that for "wank" value

But the silvertop is a perfectly reasonable choice especially if you're going to change cams or bump up the compression