Tom, all good points, however there is also the problem that the 200-4R won't take 500+ hp at the crank without a buttload of money thrown at it. The cheap way around the VSS problem is to use the sender off of a Autometer Electronic Speedo and this also has a cable drive hookup allowing you to still run a cable speedo and or cruise control. The manual valve body is needed because the modulator takes signals from the vacuum to modulate the tranny line pressure, to solve this simply use a mechanical modulator that works like a TV cable on a 200-4R or 700R4. Read this posting if you want to learn more about it http://www.turbobuick.com/forums/showthread.php?s=&threadid=107416&highlight=400+modulator The switch pitch lets me use a 1200 stall around town and then when someone pisses me off I can flop the converter over to 4500 for launch then after I bang second I can flip it back down to regain efficiency. Since I have the braketry for the cable throttle from the GN I'll just adapt up a Lokar cable to it actuate the modulator. Finally this car is a street car but with 3.07's in the Dana 44 an over drive would probably lug the engine and I can't afford the cryo and billet pieces to make the 200 live. Eventually I will probably go to an overdrive but it might just be a gearvendors unit. I appreciate the sanity check though, good luck with your conversion.
Hummm....those are even better points. With the manual modulator you can avoid the manual valve body? I had thought I had my conversion all figured out and now I may have to reconsider.... Thanks for the schooling. Help me figure out my gas tank now! What do you plan on doing?
The mechanical modulator does keep you from running a manual valvebody since is varies the line pressure for you. As for a fuel tank.... It ain't cheap but I'm going to be getting a custom stainless one from Rock Valley Antique Auto. $800 for a full welded stainless stock fitting baffled tank and with a TPI pump though he will upgrade you to a walbro 340 or whatever for price difference between the pumps. Summit sells baffled tanks with built-in sumps for around $350 I think though they are intended for Chevelles. Another idea would be to adapt in a tank out of a later B Body Caprice as they had trunk mounted spares and behind the liscence plate fillers. I've not done any research on that one beyound the fact that they spare and the filler necks are in the same locations, the tank would very likely be the wrong size but you never know. Keep this convo going Tom, 2 minds are better than one to sort out the hangups behind doing this swap! Thanks,
Hey guys, Why spend big bucks on a special tank? If you have a rust free stocker, use an external pump like an SX or Aeromotive and find a sender that has a vapor canister line to use as a return line. Save your money and spend it on other upgrades! Dave
Dave, I've heard bad things about the reliability of the external pumps due to continuous use. Another potential problem is the stock pickup location and lack of baffling. I'd like to take this car though the twisties and we all know how dangerous it is for a turbo car to run lean. I really don't want my pickup to become unsubmerged. I've never thought of that idea before though, its certainly worth considering, if only for a temp measure till I can truely afford the Rock Valley unit. Thanks,
Noisey Pumps and Stuff I had run a fast Mustang on the street with a Paxton 1000HP pump, and the constant pump wine sound drove me nuts. It would not be bad if it only came on when needed, but if I can make a single internal pump work I am all for it. When I can hang the wheels purty like Dave! I will have to step up to a big external pump. Here is my low budget idea. I am trying to think I can fit a '87 Grand National tank into the '69 GS tank area.(?) uzzled: The height, and front to back are very similar. My GS tank is still in the GS. Here is a comparison of a '72 SS Chevelle (God rest her soul) tank to a '87 Grand National tank. The '87 tank is about 4 inches wide to the left. If I could get 1.5 inches by moving it closer to the framerail, and if I can bend the filler neck 2.5 inches left also, I might just make it. Thought about compressing the ribs at the bottom of the fill neck left, and using one of those small pump-up pipe benders to work the rest of the filler:eek2: You can see the plastic baffle that keeps the GN pump nice and wet. If that does not work, I can always strap it to the truck lid like a spoiler. Ideas?
The advantage of running the TR tank would be you can get a setup that uses 2 smaller submerged pumps where the second one only kicks on on demand. The reason why that tank is designed like that is to clear the spare tire mount in the pass side of the trunk. I'm not sure I'm following your idea of bending that filler neck around and still have it work. If you put a kink in the neck you're going to have all sorts of fun trying to fill it up with out the pump shutting off on you.ou: An option I neglected to mention is that Comp Eng sells a kit to sump and then instructions on how to baffle your tank, if you did that you could feed that external pump but it was a good thing I had a nice 2.5" exhauste and spin-techs on my Riv because the whine from my Holley Blue was enough to get on my nerves just starting the car up, I can't imagine what a EFI pump would sound like. I'm still liking the idea of using the B-Body tank if one will fit or going with the rock valley tank. Thanks,
Ive got a turbo 3.8 in a 71 gs body GSX paint job. You can see the pic in the Wet Behind The Ears forum, then go to I Finally got my first buick. its by missin' 2
Hey Tom, Can you check something for me? How much different is the sending unit/pickup assembly off of the GN tank from the one on the chevelle tank? I'm wondering if we would untilize the assembly in our existing tanks (probably with some modification for depth) to allow the use of all the goodies they make for the GN. Thanks,
Grand National power for a GS Ok Sleeper here we go again. You got me thinking! I went to my favorite free!:beer picking yard and got a tank someone had pulled. They must have took it out for the the pump from an '84 Caddy Sd'V. Size looks right and neck looks quite possible. When I saw it has a plastic fuel sump like the Grand National, I knew I had to give it a try! The Caddy trunk has a nice hump that protrudes up for the hump in the top of the tank. Next trip I think I will cut out a couple of trunk humps to weld a hump in the trunk of the '69. I might even make it removable to get to the pump easy. Factory GS/Chevelle pump is about 6" deep Factory Grand National pump is about 7.5" deep Factory Caddy pump is about 9" deep It seems like the Caddy pickup is the way to go. Wiring might need to be changed a little. The metal circle p/u hold downs are from the '70 (little) and the '87/84 (big).
Not bad Tom, i'm going to be hitting the junkyard sometime soon to measure up a tank on a Caprice. The problem I can see with your tank is the ablity to get a better than stock pump. One of the reasons I picked the B-body tank is that Racetronix makes upgrade pump assemblies for it. Not sure if you can get a good Walbro pump to fit your tank. Good work though, I'd also check how low that tank will hang and possibly hit your exhauste or something. Just keeping ideas flowing. Keep in touch,
More Tank Talk! Sorry I do not get here enough :spank: It cross references to the same tank as a Caprice. Both have the same dimensions 39-3/4 X 26-1/2 X 10 inches. My big fat Walbro fits the Caddy/Caprice hanger. Wiring is a little different, but should be no problem. Low is not a problem if I create a hump in the trunk, for the hump on the top of the fuel tank. An access hatch to get to the pump? uzzled: I will PM you my phone numbers, and you can get ahold of me anytime. Tom
Where could I get one of these 3.8/200 4r's? I looked alot of place but can't run across one. I saw one on ebay but it was half the nation away. Mack
As far as locally to you, no idea, however there is generally all the pieces and sometimes whole drivelines on www.turbobuick.com. That would be my suggestion on where to start. As far as foundation is concerned, if you get a regular NA 3.8 from a rearwheel drive car 86 and on they will have everything the same as a turbo 6 except pistons, crank, and the specialized intake and headers. If you need more help piecing it together I'd be glad to
tank options Hey guys. I'm a lurker here but thought I'd give you another possible option on the tank. I'm using a Tanks Inc. polyethylene tank in my Turbo Buick powered '36 Chevy. They have a kit that includes a "pan" type setup to keep fuel around the pickup and uses factory pump hangers. Considerably less money also. I've got about $400 in it (minus the pump). They will supply a Walbro 340 if you request it. HTH, Richard Gautier SinistrV6 on all the boards
