Howdy!

I bought an L-98 complete with TPI, wiring harness, ECM and sensors to drop into my '58! I'm keeping as many of the senors as possible (O2, exhaust, etc.) However, since I'm bolting up the T-10 4spd. Tranny from the '58 to the L-98 I lose the speed sensor. What do I have to do to the ECM (or what do I do???) so that the car doesn't think it is in limp-home mode. I'll also be trasing the smog pump, AC compressor and power steering. How badly will this confuse the ECM? The block is from an '86 (since I know they changed the ECMs around on different model years.)

Any/all info is appreciated.

 

Congrats...we'll try to steer you in the right direction.

1) Shouldn't be a problem. Just make sure that you get ALL the sensors because 5 $20 parts can add up quickly!

2) I might be wrong on this one. Isn't the 4+3 a Doug Nash T-10 with an adapter on the hiney? But I suppose the sensor would be coming out of the overdrive unit. Hmmmm. I would look into part numbers for third gen speed sensors. Some of them had a T-5 and that could possibly work. I mention the 3rd gens because I know that a lot of them used a mechanical drive-spedometer as opposed to ours which were all electronic. The main rumor on the street is that VSS is used for convertor lockup (which you won't have) as well as some other things like part-throttl coast down. See what you can find as far as a speed sensor and if your search comes up empty, then start worrying about what to do if you can't find one.

3) Those 3 things won't confuse the ECM. Are you keeping EGR? Keep in mind that the base calibration (EPROM image, BIN, whatever) will be programmed assuming you have EGR on your vehicle. Since it is a 58, I assume you won't be running it, which is not a problem. Would take a little chip tweaking however.

You didn't ask, but I will say some more stuff :D

I would suggest going with a heated O2 sensor. Cost is only a few bucks more than a normal one and you won't have as many headaches. As for location of the O2 sensor, it varies with the type of manifold/exhaust you want to run. It needs to be kept hot. I have seen Dr J has post a few ideas on O2 sensor tech either here or on thirdgen.org.

VATS will most likely have to be disabled in the EPROM.

Are you going to be tuning your calibration in the chip or have someone else do it? Stuff like no EGR can be done, but it needs to be removed not just physically but correctly in the chip.

Good luck. -Matt-

 

Cool project. I never knew whether the '58 or the '62 was the best-looking straight axle, it's a tough choice.

Anyway, is the L98 from an F or a Y body? A Y body ECM will want an AC signal from the VSS (magnetic pickup) of 4000 pulses/mile. I thought the F body used an optical pickup, not sure.

The ECM will want that signal for idle control. If I read your syntax correctly,you are using the orighinal T-10 trans? If so, I think HH is right, check with some Camaro guys and see if there is a tail shaft from a 3rd Gen (with a VSS built in) will swap with yours directly.




[Modified by DOCTOR J, 8:06 PM 6/29/2002]

 

The L-98 is from an '86 'vette with auto tranny. I'm going to use an L-98 clutch/pressure plate/flywheel with the '58 bellhousing and '58 T-10-- so the driveshaft should line right up. The 350 from a bolt-in/line-up perspective should fit right in. I do have a C4 Haynes manual and a the JRW publishing "Chevorlet TPI and TBI engine swapping" book on order.

I just need to know who/how to fix the ECM so it doesn't require signals I can't give it (PS/AC/VSS/VATS/smog pump) and still have a car which runs like a scalded dog :D

:chevy

 

I think that you are going to have to run a VSS or the ECM is going to barf on you all the time. I think that the biggest issue is going to be idle control. What I would recommend is that you contact JTR (Jags That Run, )http://www.customconversion.com/) & ask them what they recoomend. I think that you are going to want to get a Magnetic VSS, IIRC the 86 is a MAF setup, so maybe that is not right. in any case, you might have to put on a 90* adapter to get it into the tunnel, I did on my conversion (71 camaro) it worked out for the better anyway, fitment is better.

I think that the only real issue you are going to have is the VSS & VATS, I dont think that the ECM is really going to care about the other stuff. You can get a copy of winbin or any other free editor & turn those off rather simply. depending on setup, you might end up wanting to do some editing to it anyway to get it to run as you would like

hth's
BW




[Modified by Bobalos, 2:45 PM 7/3/2002]

 

The 4 speed unit is a Borg Warner Super T-10 with DNE stamped on it. The speedo sensor is on the OD unit where the normal tail section would be and is electric.

 

The JTR book came via FedEx this morning. Yes, the 4+3 is a T10 w/ some custom stuff on the rear. JTR/Stealth Conversions make a dohickey you stick on the mechanical speedo output on your tranny which sends both the necessary signal for VSS and passes the mechnical speedo through so you can still run your speedometer. So I'm good there.

The only items of trepidation left are if the ECM requires input from power steering and/or the AC. I hopefully can find a way to run a mechanical tach off of the alternator (maybe just by bolting on the gear reduction unit from the generator, which is known to work on some GM alternators.) It looks like the L-98's water pump will drive a real fan to blow on the radiator, so I'll just bolt my existing fan to that. The brass radiator I have should have enough capacity for a 350. VATS is the only other thing I have to worry about, and since we do have keys to the wrecked car we can get the resistance which we need.

Thanks for the help/pointers!

 

OK, I have done this swap into my '72, and over the 6 some odd years of owning this combo....I have several suggestions...
first use GM #1227730 computer, rewire or buy a harness for it,...
eliminate the cold start injector...just unplug it is fine for now...
put the O2 sensor in the heat crossover flapper valve, which you will cut out ahd weld up the other hole....weld the bung or tap the hole you wish to use...
if you are using headers, you need put it in the collector and it will require a heater sensor....just two additional wires...one to the ignition or fuel pump source, other to engine ground...
the Vss will have to be replaced in your original tranny, what you need is an adaptor type...has the mechanical speedo and the additional 4k/mile pulse train needed by the 730 computer....
when you buy a reprogrammed chip, you need tell Ernie at Breathless Performance to eliminate VATS, as well as a good bit about the engine...any mods, etc...
the stock water pump is reverse rotation so it's needing either a reverse, or an electric fan....I recommend an electric fan in the OEM shroud...big as you can find....also maybe a new aluminum radiator from your AC Delco indepandant dealer parts house...NOT a car dealer.....less than 200 bux will probably get you one to fit nicely in stock mountings...may have to splice fab up hoses, but that's no trouble really use 1.5 inch copper plumbing pipe for splice incerts...
use K/N oval air filter over T body input, simplest thing to do....
the 730 computer is speed density, so you do not need plumb/wire the MAF, makes life simpler that way....
you need decide an ideal easy to access place for your computer, in the pass compartment near the firewall....I recommend route the wires on pass side also, through fire wall....simpler for accessability....

email me off line if you want,...maybe some further suggestions....

but ONE thing...you are going in the right direction.....keep it up....

mrvette72@interstateweb.net

GENE

 

Thanks for the help :D

I do have the VSS sensor on order from JTR/Stealth so that problem is solved.

I plan on using the stock exhaust manifolds from the L-98. They look like they'll line up with the stock '58 exhaust! Plus, the exhaust I have has a front x-over, open-chambered mufflers, and a rear x-over, too so it should work pretty well.

Thanks for the head's up on the fan. I'll get the reverse-fan and keep the existing brass radiatior setup for now. I'm planning on getting/making nice custom stainless hoses for the cooling system. How hot do L-98s typically run?

Speaking of hoses and lines, how did you run the return line from the FI unit to the tank?

I'm going to use an external electric fuel pump (as opposed to something in-tank... I just invested in a new, proper, stockish fuel sending unit and don't want it to go to waste.)

Many Thanks!

 

Completely stock do not be surprised to see something like 225* oil.