RamJet 350 Swap

[Mr_Roboto]

Beautiful van, so clean and a fairly rare combination as mentioned. A black shorty AWD is definitley my dream van, but a cargo instead of the full windowed one.

That's a full weight van, so I don't quite know if I'd do any sort of high stall torque converter in it, just because it's heavy and you tow. The cam in it is quite tame though, so if for some reason you decide you want "more" you have a lot of room to do it honestly between the cam and the converter. That intake is also a great design, the torque curve is super broad, and will give you a ton of room to grow if you so desire. If you have 3.42s, you may also consider some more gear, with some 4.10s and your tires appearing to be 27 inches tall, you have quite a bit of potential, I'd bet at least low 14s with no rear seat/jack/spare if not dipping into the 13s.

[delsafari]

Mr Roboto,

Thanks for your comments and suggestions. I too like the cargo version - in fact, a major reason I wanted black was to imitate the cargo with the tinted windows. But I wanted the best of both - the cargo "look", and the visibility provided by full windows. Also, I don't think the cargo models come fully optioned, which I also wanted.

I agree on the torque converter. I was told that the AWD already has a higher stall torque than the 2WD vans - like 1800 rpm. Is that true?

Good to know about the cam. Changing the rear end from 1:3.42, to 3.73 or 4.10 would increase power / acceleration by effectively lowering all the gears - right?? Disadvantages would be increased rpm at highway speeds, and decrease gas mileage. I don't think that wouldn't be worth it for me. This swap was not only costly, but now I'm burning premium, and the mileage is lower (don't ask me what it is, but it is lower). Prices here just hit $1.29 per liter, which is about $5.20 per US gallon, $6.00 per CAN gallon. Takes well over $100 to fill the tank, and that doesn't last me a week.

Tires I'm running are P255-60-15, same diameter as stock, but wider. I'm using rims off the 2WD 1/2 ton truck, which have the same bolt pattern, and look similar to the OEM alloy rim (but chinkier). The rim is 1" wider than stock for the van, which helps with the wider tires.

Maybe if I ever retire it from being my daily driver I will consider further performance upgrades.

[Mr_Roboto]

Do not know on the stall of the converter, it may be lower actually due to the added weight. For a similar "K" factor (how they measure slip) if you have more weight the stall speed goes up slightly. The common swap in the day was a 2200 RPM S-10 4.3L converter, or a 'vette converter both of which are 2200 stall. Naturally, you lose some mpg with that but less due to the lock up at highway speeds. The gears are nice if you tow, and if you tow a lot the sacrifice in cruise RPM may be worth it to you just so you have extra towing ability. Another thing is that with some mods you can probably tow in OD, which would gain some mpg.

[peter]

BUMP, just in case you thought we forgot your promise to run her at the track

[delsafari]

Peter,

Nice to hear from you. Matter of fact, I've recalled my rash promise on a few occasions, and debated if and when to try the 1/4 mile. Thanks for the reminder! I've been busy and haven't visited the ASV site for a while. I'll see what I can do.

I have just been enjoying the van every day - hauling, towing, and just torqin' around, enjoying the rumble and the tunes. But the price of premium fuel is getting painful.

I finally checked the mileage - highway travelling, at 120 kph (73mph or so) I get 18.2 miles per gallon (Canadian gallon that is). That would be about 14.6 miles / USgal, I think. (Don't ask how many litres per 100 kilometers - the official standard in Canada). Towing the boat, about 4000 lb, I get 12.6 mpgCDN. Toolin' around town the mileage is worse of course - I haven't checked - don't want to know.

Towing is great with the V8. Lots of power, stays in OD on minor grades, unlocks and shifts down when needed. Beautiful. Still the original tranny and transfer case, with 450,000km. I just had the factory eprom tuned for shifting with the RJ350. Original converter, etc.

On another note, I was looking forward to find out if my flex fan, with no shroud, would keep things cool in summer towing conditions. My swap installer didn't heed the advice on trimming and keeping the radiator shroud. He tried to use an electric fan, but said there wasn't enough room, so went with the flex fan. He assured me it would be OK.

Well, it cools just fine, whether towing or not, AC on or not, EXCEPT on two occasions, at low speeds (like idling) when the weather's hot. One time the MEFI controller switched into limp mode, limiting RPMs until it cooled down. Weird. As soon as I got moving it cooled down. Seems to me I need a shroud. So, I'm in the process of finding a used one to see if it can be modified and installed. My original one was tossed. GM only sells the bottom half, top not available. Maybe a custom metal one could be made. Any suggestions / comments? It's relatively minor in this cool northern climate, but I want to get it resolved.

[s10-den]

I just scanned throiugh here, nice write up!!What did you do for the ramjet wiring?

[delsafari]

s10-den,

The RJ 350 crate motor comes complete with its own wiring harness, computer, etc.. Just had to hook up some engine signals to the van's ECM so it could control the transmission, and tuned the existing eprom for the V8 and motor specs for correct shifting.

Since I didn't do the swap myself, I don't have a lot of details.

By the way, I got the fan shroud installed, and still have the problem of heating up at idle when weather is hot and AC on. Don't know if it would go into overheat (limp) mode if I let it run a long time. So, for now, I turn off the AC when ordering at McDonalds drive-through in hot weather.

Not cool.

Any suggestions??

[peter]

The fact that it only does it at idle means your lucky. You cooling system itself is big enuf, just not getting enuf airflow.
There's no reason you can't fit the OEM clutch fan back on, judging by what I've read on this site. That along with the OEM shroud trimmed back should make everything ok again.

Myself, I'm running Flex_A-Lite 295 twin electrics. 4600 cfm. Comes c/w shroud and electronic speed controller from 40-100% plus soft-start. If you can't cure your problem with an OEM clutch fan or better shroud, that may be a route for you. However, I suggest you wait a bit. Alot of sbc swappers here have experience and have all sorts of tricks in their bag.

PS: One of the coolest things with your swap is that you managed to use the truck 'puter to control the tranny. I simply bought myself a tranny controller from CompuShift. I love it 'cause you can set shift speed, kickdown percentage, tow/haul firmness and adjust for tire sizes. But it cost $1200.
You stuck with it and managed to get the OEM 'puter to do the job. Good for you

PS: Is it possible that your flexfan is running backwards? It does strike me as strange that even with a shroud, you'd be experiencing problems. If it isn't turning the wrong way and your shroud actually "shrouds" , another approach would simply be to add an electric fan to the condenser side. That should help out quite a bit. I personally am not a fan of electrics on the front side of the stack due to the disruption of airflow when the vehicle is on the highway, but many have done it and are happy with the results.

[s10-den]

Like he said above me, if its only at idle, then you have an airflow problem

[delsafari]

Thanks for the suggestions on the overheating.

I agree it's a flow problem, since there is no problem as soon as I get moving, and air is flowing through the radiator.

I picked up a clutch fan at the wreckers hoping to have it installed when the shroud was re-installed. The mechanic that did the swap has moved on, so I was hoping a different mechanic would find a way to fit it in. But they insist there is not enough room between motor and rad. There is a 2 inch spacer behind the flex fan to position it closer to the rad, but even with that removed, they say not enough room for the clutch fan.

I will check on the rotation of the flex fan. You never know. Wouldn't that be nice, something that simple. And I will not rush into anything. Cooling shouldn't be a problem for the next 8 months or so in this part of the world. I'll keep the electric option in mind too. That was actually the first choice when doing the initial swap, but the shop said it wouldn't fit either. That's the problem with not doing my own work - the shop isn't as persistent as I would be. Even though they do custom work, they aren't motivated to find the perfect solution. Takes too much time for them. My problem.

Peter, I agree it is nice to have the truck computer controlling the tranny. When we tuned it, there seemed to be no limit to the parameters that could be adjusted. But it was a one-shot deal, for $600. And if I want to change it, I would be paying again. Wouldn't take long to spend $1,200, although at this point, there's nothing I would change. So, your Compushift controller doesn't look so expensive, considering you can probably change settings whenever you want, for "free". Trade-offs, both good solutions.

Still thinkin' about getting to the 1/4 mile strip. Very busy renovating. All in good time.

[chartman]

What was the part number for that Trans flex plate cover i see in your picks? I've ordered two different and they both didn't fit the 4l60e. I've been driving without one for 40K miles.

[delsafari]

Hello Chartman,

Sorry for the delay, was away on a cruise, escaping the Canadian winter.

As I recall, the shop that did my swap assumed the plate off the 4.3 L would not fit, so they brought in a different one, shown in the picture with the exhaust manifolds. I assume that's the part you're referring to - I'm no mechanic, and the details of my swap are getting a bit fuzzy.

Anyway - if that's the part - it turned out the new plate was not right, and the old one off the 4.3 did fit, so they used it and returned the new one.

I could look through my records for part numbers if you want more information. Let me know.

I will reply sooner next time.

Delsafari

[sfeaver]

will this work?

[delsafari]

Sorry, but I don't think I can help you on this. I commented on the flex plate, but you are referring to the cover.

I checked my materials lists and there is nothing about a flex plate cover. I don't remember seeing it or discussing it with the mechanic that did my swap. I'm not sure where you see it in my pictures either.

Maybe one of the more knowledgeable guys on this site can help.

[delsafari]

Here is an update on my cooling problem, now resolved. Maybe this belongs in a different section, but it follows previous posts, so here goes.

My flex fan with shroud was not working well enough in all situations, especially when going slow or stopped in traffic. So on advice from the guy that recommended the Ram Jet 350 to me in the first place, I looked at SPAL electric fans. I went with a twin, Model 2VA06-AP70/LL-37A, rated at 2700 cfm (at 0 mm H20), or 1770 cfm (at 15 mm H2O) - I don't know what pressure they are usually rated at. This fan's size (23.5" x 16.25") covered most of the radiator area. Available space between the rad and motor was a problem, but this model worked because the recess between the two fans allowed enough room for the motor shaft to extend between them - where the OEM fan mounts, leaving about 0.5" clearance.

Unfortunately the shop installed it upside-down, so the damper flaps may not work exactly as designed - don't know for sure. The theory is - at higher speeds the flaps are pushed open by air flow, allowing better cooling without the fan being on. At lower speeds / stopped, when the fan is on, the flaps close to increase the shroud effect. With the flaps now attached at the bottom instead of the top, they may hang open, not closing as readily at low speeds / stopped. In spite of being upside-down, it seems to work well, so who knows if it matters?

The fans were wired to turn on when the AC condenser is on, and / or via adjustable thermostat. The AC / defrost function worked well, but the thermostat control did not, even when set to the lowest temp. The temp sensor was installed between fins on the radiator, which the shop assured me was correct. This left me with a situation where if the AC was not on, it would occasionally heat up if sitting in traffic, or going very slow, depending on outside temp. And I could not have the fans on while towing on the highway in warm weather without AC on, and in extreme situations I want to have that scenario for maximum cooling.

To improve this, while on summer vacation in Montana, I had a manual toggle switch installed on the dash so I could turn the fans on any time. The shop installed the switch without a relay, and a few months later the switch melted. Nice. So I had it reinstalled with a relay, which works fine now. Even so, having to manually turn the fan on is pretty low-tech, and it's still easy to not notice a climbing temp.

So I recently had the thermostat temp sensor relocated up against the rad hose, which is a metal flex hose. A short piece of rubber rad hose is wrapped over the sensor and flex hose to secure and protect it. Now the thermostat works fine.

So think that now I have a good cooling system. I know there are other more complex ways to control them, like soft starts, variable speed, and single / double fan operation. But my basic installation was problematic enough, I think I will just leave it as is.

For me, the vehicle is still well worth it. Its a sweet van and I enjoy driving it every day.

I also recently replaced the muffler with a quieter one - because I'd rather listen to tunes than the drone at certain rpms / speeds. Even with the amplifiers in my sound system, less background noise is better. It may cost me a few HP, but there's still plenty of power, and the RJ350 still sounds great when I stomp on it.

Hope that's interesting or helpful to someone. Any comments would be welcomed. If anyone wants more info or some pictures, let me know.

That's it for now.

delsafari