Guest Dan0myte Posted July 20, 2001 Share Posted July 20, 2001 Hey guys. Just started researching and planning a 240 to GN swap a few weeks ago and so far, so good. Take a sweet little japanese sports car with tons of underhood room and swap in one of the greatest performance-potential engines out there, just sounds too good to be true. Anyways, been doing a lot of reading around different UBB's and still wondered about a few things. 1) What kind of cost am I looking at, just to get the car running with the new engine? No mods, nothing yet, just stock 3.8 engine, stock Z. 2) Is the concensus to stay with the stock GN automatic tranny, and if so how easily does the shifter and such retrofit into this car? 3) Which swap parts can be bought and which will have to be fabricated? Thanks guys. Don't know what I'd do without the internet. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 20, 2001 Share Posted July 20, 2001 i haven't a clue to pricing, Im sure scottie-gnz will answer all of your questions, but I do have two cents to add about the trannie... in general, auto. trans are bulkier that manuals. I.E. harder to fit in. also, GN's are a big collectors item so (now this is just speculation) it might be cost prohibitive to buy a gn to gut.. so you would probably have to purchase the trannie seperate... in wich case wouldn't you much rather have a t56 (6speed) ? On the other hand, i hear that in the case of the mkiv supras, the auto trannie is faster than the manual for draggin... now knowing how s.h.i.t.t.y. my auto trannie is, IMHO they just need taller gears/and or more driver skill... but it is a factor to consider... hope I helped more than I confuesd Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 20, 2001 Share Posted July 20, 2001 Warning, THIS IS LONG Dan, it is too good to be true but I and others are living it. Allow me to ramble a bit . Couple of things I want to say up front. - There is no kit for the Buick Turbo, so the cost will depend on how much you can do yourself or if you have help at a reasonable cost. - If your HP goal is 300 or less, I really do not believe there is any advantage to the Buick Turbo over an LT-1, LS1, mildly-built SBC or SBF. I personally believe the cost is about the same but the advantage of the Buick is when you want to go to next level, 400+hp. BTW, all my references to HP is RWHP, measured by how effectively you can put it to the ground. Having 500hp is meaningless if you cannot put it to the ground. The cost of a complete Buick Turbo drivetrain will run between $2500-3500. MOF, one guy on the Buick board currently has 4 for sale. http://www.turbobuick.com/forums/showthread.php?threadid=7635&referrerid=1951 Motor mount brackets - these have to be fabbed. Mine are welded onto the crossmember so I cannot duplicate them but if you look at the pics in my site it will give you a good idea of what is needed. Tranny mount - a simple affair that bolts up to the floor. I am sure the JTR one will work but I have detailed specs on mine if you wanted to duplicate it. Driveshaft - full GM shaft cut down with adaptor for R-200 diff - $200 Shifter - you can use the stock shifter with some mods, if you have one. Be aware it does not have detents in the forward gears. If you have to get something, then get an aftermarket unit. I have used the B&M Pro-Stick and currently have the Pro-Ratchet. - $50-$175. Exhaust - You will need someone to bend you a 3" mandrel exhaust or weld up pre-bent elbows and have it connected to the stock turbo wastegate elbow. I had one and sold it CHEAP. Here is what it looked like and you see it is not nothing exotic (a 45-degree and 90-degree elbows cut and welded). I had it ceramic-coated. Notice the top where the 3" pipe is grafted into the stock 2.5" pipe with the flange. the rest of the exhaust can be 3" with a single straight-through muffler. Wiring/ECM - you can get the stock harness and ECM and if you are good with wiring, eliminate a lot of the wiring from the harness that is not needed. Another option is to buy a harness made for swapping this engine into other chassis. Pricey but may be worth it if you do not already have a harness. - $500 BTW, the harness is totally independent of the Datsun wiring so there is no grafting, etc. Raidator - best deal out is the 24x19 Griffin aluminum with a good electric fan. The radiator is $189 shipped and search the archives for posts on the Taurus fan. Intercooler - You will be moving a lot more air than the L28T so low-cost I/Cs like the Starion, Saab, et al, are not an option. At a minimum, you need the big Isuzu NPR. You can also use the SupraTT unit since it supported 320hp from the factory and should be plentiful as there is not a SupraTT out there running the stock I/C . Seen that for less than $100 on e-Bay. If you get a stock Buick I/C, it can also be adapted to be a FMIC. Mandrel plumbing is a must with 2.25" turbo-I/C and 2.5" I/C-TB. Depending on which I/C and how cheaply you can get the plumbing done - $300-$500. The initial entry fee appears high but I think compares well with a V-8 engine swap that can match the performance of the Buick Turbo. Either swap will require mounts, driveshaft, exhaust, shifter and radiator. The differentiators are the turbo plumbing and the cost of the drivetrain. That is why I think at stock HP levels, the cost will probably be even (MAYBE). First time I ran my car was with an easy launch (2.19 60'), 3.90 gears (BAD!!) and it ran 12.41 @ 114.7 in pump-gas mode. That equates to about 325RWHP. All I did in addition to what was listed above was a chip, $35 used. I had larger injs but they are not needed. I also bought a scantool for tuning. So for $235 I went from the stock (under)rated 247HP to 325hp. It takes an LT-1, LS1 or mildly built smallblock to match that and I imagine the smallblock will cost the same. The advantage of the Buick is when you want to go beyond 350HP. Race gas, turn up the boost and tune, tune, tune. The Buick turbo was designed to run with the TH200-R4 and it works well. Ask a Buick owner if it will work with a 5-spd and they will tell you no way. It will, but as stated in this thread, the gearing is key. This engine is a low-revver (as opposed to a slow-revver). Mine currently shifts into 3rd at about 150' in less than 3-secs on a hard launch and with a manual, you had better be real quick. The manual swap has been done and you can search the archives for info. You need a tranny/rear combo that will not wind up the engine too fast in 1st and 2nd. You had also better get a STRONG!!! gearbox. The strong suit (pun-intended) of the Buick turbo is low-end torque and when you get up in the 400HP range the torque is over 500Lb-ft at idle. OK, maybe it is not that low , but you get the idea, that is big-block territory. Most of what I described can be seen on my site. Good luck with your choice. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 21, 2001 Share Posted July 21, 2001 Heh, DO IT! Scottie needs some more competition in the race for the 10's Scottie's car is running about an 11.1 at some ungodly MPH shifting into OD way before the traps. His problem seems to be gearing that's too steep - can you imagine a problem like that? Keep the auto, add a trans brake, and have a blast. Scottie's car is just plain sick on the street, he has to detune it to get it to stay on the road! Quote Link to comment Share on other sites More sharing options...
Guest Dan0myte Posted July 21, 2001 Share Posted July 21, 2001 Thanks for the detailed reply Scottie. Great to have people around that can answer questions like these. Ever thought about making and selling a GN swap kit? Could make you a ton of money for more mods to your car. Quote Link to comment Share on other sites More sharing options...
Guest Dan0myte Posted July 23, 2001 Share Posted July 23, 2001 Another quick question, where are the EGT probes normally mounted on a GN motor? I know in my current car, I tapped it into the #1 cylinder before the turbo. Is there a place like this before the turbo to tap, or do most tap after the turbo? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 23, 2001 Share Posted July 23, 2001 The EGT probe on a GN goes before the turbo, in the general location as the O2 sensor. If you are familiar with the GN engine, below you will recognize the turbo end of the passenger-side header. The "hump" on the right is the O2 tap. The clamp-type probe like you see here just requires the right size hole, not a tap. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 23, 2001 Share Posted July 23, 2001 Hey Dan - I am doing the 3.8 turbo in a Datsun Roadster. I was fighting weight and the SBC was wayyy to heavy. I bought a N/A 3.8 and a carb turbo system from a 78-79 GN. I am looking for 250 to 300 HP thinking that is all a 2000 pound Roadster needs. I am also using a WC T5. I could not get myself to put an auto in a Roadster and I don't think I could get one to fit if I wanted to. On gearing - I have a friend that builds V8 Zs. In the last auto trans he built, he put in a short first gear. He uses it to get him just rolling then hits 2nd. His times dropped. This keep him from spinning too much - get forward momentem going, then to full power. Phil Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 24, 2001 Share Posted July 24, 2001 quote: Originally posted by SPL311: On gearing - I have a friend that builds V8 Zs. In the last auto trans he built, he put in a short first gear. He uses it to get him just rolling then hits 2nd. His times dropped. This keep him from spinning too much - get forward momentem going, then to full power. Phil Hmm. The 3.27:1 first in my Tremec TR-3550 is super short with 3.7:1 ring and pinion and even 26" tires. I will try that launch method (some day when I drive it some year ). Thanks. Quote Link to comment Share on other sites More sharing options...
Guest Dan0myte Posted July 24, 2001 Share Posted July 24, 2001 So what's a normal reading for an EGT probe in a location like that? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 24, 2001 Share Posted July 24, 2001 My target is 1575* at full boost. Have not done any tuning with it for "normal" driving. [ July 24, 2001: Message edited by: Scottie-GNZ ] Quote Link to comment Share on other sites More sharing options...
Guest Dan0myte Posted July 28, 2001 Share Posted July 28, 2001 Sounds good. How's this for a newbie question: what makes the GNX engine different from a Gran National engine? Is it worth it to try and track down a wrecked GNX or will an engine out of a GN hold the same amount of power? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 28, 2001 Share Posted July 28, 2001 Dan, you will NEVER find a GNX engine and it is not worth looking for as you get can more HP from a "regular" 3.8 turbo with mods. The GNX had an upgraded turbo (ceramic impellers), ran more boost, had a more efficient I/C, more aggressive chip in the ECM and a better exhaust system. If you are looking for an engine, it does not have to be a GN. The Turbo T-Type had the same engine as the GN so just look for a 86-87. If you are building a GN-Z you want to start off with a good I/C, free-flowing exhaust and chips are dime a dozen. The GNX ran 15# boost and with more octane you can run 17-19# on the stock turbo and far exceed the HP of the GNX. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted July 29, 2001 Share Posted July 29, 2001 GN... drooool. Scottie, your THE man. I never really said anything but I am VERY interested and read everything about the GN swap. I love it, domestic, and original!! IMO, very impressive. Nice job scottie. I think its an excellent swap. Evan Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 29, 2001 Share Posted July 29, 2001 You should see it run in person Evan. That sucker fights for traction! Clean install and just so weird to see a GN under the hood when you open it. Parked next to a LINE of GNs most folks who wandered by didn't even realize what had been done, it was a riot. Scottie pulled on my RX7 no problem even with little traction. It must be a rush to launch that thing on the track! I too read everything about this swap I can and about the GNs in general. I only wish GM would build another worthy turbo RWD drivetrain like this one... Quote Link to comment Share on other sites More sharing options...
Guest super280z Posted August 3, 2001 Share Posted August 3, 2001 in the event that noone noticed, there's a gn complete motor for sale on the gm6 cylinder board. turbo, computer and all. i know that you guys are always looking for exotic powerplants as am i. i just happen to know where there's one for sale. check out the board or make an offer. e-mail my post name @hotmail.com with questions. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted August 3, 2001 Share Posted August 3, 2001 LOL, just you wait - 5mins after that puppy is sold someone will want it! Scottie has posted abut GN drivetrains being for sale on other boards here a few times and they're always snapped up real quickly. I do wish a stick were a little easierbettersuited with that drivetrain as I don't much like autos but that sure would be a nice combo. Too bad my V8 swap is nearly done else I'd have been REAL tempted after having seen Scottie's car... Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted August 3, 2001 Share Posted August 3, 2001 hate to say it, but im sick of dicking around with my z for quite sometime now. The GN swap would be cool, but im just no longer up to that kinda work.. .HOWEVER... I drive a chevy S10 and in the next few years, maybe after i roll over 110000 miles, and get some dough it may become a new bodystyle syclone!! Awesome motor, just awesome= Evan Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted August 4, 2001 Share Posted August 4, 2001 Just for you, Evan. http://www.sportmachines.com/magrack/truck_sport_utility_2-93_1.html Quote Link to comment Share on other sites More sharing options...
Guest Dan0myte Posted August 12, 2001 Share Posted August 12, 2001 Hehe, what a great forum. So let's say I had $8k to spend on this project, do you think a cheap 240Z could be bought, repainted with any rust spots fixed, GN swap done and driveable? That's kind of what I'm working with right now. I don't really have any metal fabrication tools at my house here, so the install would have to be done by some sort of shop. It's very, very tempting, but I just want to make sure it's a possible option before I go ahead with it and end up with an engine-less car stuck in my garage. Quote Link to comment Share on other sites More sharing options...
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