Scottie-GNZ

You mentioned you had a buddy with a Malibu with the GN drivetrain. Is this the one, hehe. Being Hybrids, we can all appreciate this one. <img src="http://www.mindspring.com/~vscott911/dscf0145.jpg">

Pete, what a coincidence, I just got rid of a 91 GSX that was my daily driver because I needed a vehicle that could haul STUFF to the track. Tires, floor jack, tool box , some spares and the requisite cooler, if you know what I mean. Your comment about driveability is actually the opposite of what you think. Most GNers stick with the stock cam up to and beyond 450hp. You are generating HP from the ability to increase boost without detonation. It is not boost that kills turbo engines, but detonation. With no internal changes to the engine, when not on boost, it runs like grandpa's Buick and gets his mileage too. In the V-6 section, I posted a link to recipes to hop-up the GN in stages from stock, to 300hp, 350hp and 430hp. What is interesting to note is that up to 350hp, discounting a freer flowing exhaust system, not a single component was added to the engine. Just increase the octane, increase the fuel pressure and turn up the boost. For 430hp, a larger turbo, downpipe and increasing the fuel capacity with injectors and pump. My car has 3 "modes". Normal driving w/o boost, boost with a "street chip" requiring at least 93-octane and boost with a "race chip" requiring 108-octane. The 2 chips, because of the required octane, have different boost levels and timing curves. I do not have one yet, but there is a special chip that allows you to have up to 16 programs and with the roll of a thumbwheel, I can go from econo-car mode to a fire-breathing mode that matches my octane level when that Viper pulls up next to you at the light Now you know how a 600+hp GN can be driven on the street to the track with 93-octane, run 10s and drive home, w/ac Scottie

Andy, thanks. Pity your buddy with the Malibu did not exploit the GN drivtrain. For a modest investment of about $200, he could have bought a scantool to data log and tune and extract another 100hp without spending a dime on the engine. I made mention mention of Derek Grubb's car in an earlier post and sure he would not mind if I continue to wax gloriously about it. The info in this link is a little dated and I posted the latest I know earlier. As you look at this car, ask yourself this: If you were driving a real hot street car and pulled up next to him at a light, would you give this car a 2nd look? http://www.eng.fsu.edu/~jthagard/otherzs/Derek/derekGN.html Scottie

If anyone is comtemplating an engine and wondered about the potential of the GN engine, here is a link to some recipes for tuning this engine in stages. As you read it, keep the following in mind: - The HP numbers are calculated from the car's performance so it is RWHP, not flywheel as most ads show - A Z-car will be about 700-1000lbs lighter than a Turbo Regal - When you look at the performance numbers and play "what if", figure on .1 sec quicker for every 100lbs less or plug the HP and weight in the formula Ron posted at http://www.race-cars.net/calculator/et calculator.html - The hot SBC advertised at 460hp is probably 370RWHP. Notice what it takes to extract 350 from the GN engine and the next stage with a turbo upgrade made 430. I played "what if" and plugged in a 2700lb Z with 350RWHP and got 11.5 @ 118.4 and with 430RWHP I got 10.7 @ 136. Derek Grubb is probably at the 430 stage with his 71Z and he ran 10.5 @ 129. http://www.gnttype.org/techarea/recipes/Staged1.html Scottie

Is an SBC the only option? Did you ever consider a Buick GN? Of course, if you must have a manual trans then it is not an option. Ironically, it has been proven that a manual trans slows down a GN. If it is an option, I believe for $4500 you could buy an entire drivetrain, have it freshened up, mild head porting, good turbo and injectors and have 425hp AT THE WHEELS, not at the flywheel like measured with the crate engines. My engine/turbo is bone stock and based on the performance I have already seen, I am projecting low-11s @ 100-high-teens. Derek Grubb from PA has a daily driver with big turbo and headwork and runs 10.5 @ 129. With the stock IRS, halfshafts and 6" slicks, he cuts mid-1.40s 60'. HOW DOES HE DO THAT? Just thought I would throw that out as an option. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html

I like it! It must be using a similar type equation because the results are the same as mine and it did not even ask for ET when calculating HP, which enforces my point about MPH being the key. I ran 12.41 @ 114.7 with a soft launch and it said I had 325RWHP. I was guessing with a decent launch I would have run 11.8 and when I plugged into the other formula giving it weight and HP, the results were 11.88 @ 114.7. Should be able to better that with the McCrearys, transbrake and some boost off the line. Would love to see low-11s with race chip/gas and more boost. Do you have a website where I can see more details on your car? Scottie

Chris, in case you are interested in seeing what a Z-car looks like with the 5-spoke Revolutions. They have been on the car for about 14 yrs. Scottie

GN conversion was only started last December. A black car really looks good with a fresh wax job and the right light, hehe. But seriously, My buddy and I rescued this car ('71) from a boneyard over 20yrs ago and the bodywork and paint is over 19yrs old. Up close it shows its age and it had an accident since that shot last summer. Psy, the wheels are 15x9 revolution 5-spoke all around. Front tires are 225/55/15 and rears are 245/50-15. High-perf springs (cant remember brand), Tokico Illumina shocks, lots of poly bushings. Front brakes are 82 280ZX front calipers and 84 300ZX vented rotors. Rears are 82 280ZX clipers/rotors, plus early ZX 15/15 master cylinder. Another key to the suspension are the F&R strut tower braces and the 6-pt welded rollcage. Amazing what they do for a car's suspension. The flares are ZAP and were purchased through the now-defunct National Z-club in NJ. I believe one of the Z-car vendors still sell them or a copy. Scottie

I have flares and stock springs. My wheels are Revolution 15x9 with a 4.5" backspace and I clear the springs fine with 245/50-15 tires (24.6"). Where I run to problems is trying to run a taller tire. I mounted up some 26.4" tires for drag racing and they hit the spring perch. So, I would say 16" rims with the popular 245/45 size at 24.88" would fit fine. If you get coilovers you solve that problem and could probably even go with a 5" backspacing and be safe with even wider wheel and tires like the 15 or 16x10 and 285s like Mike mentioned. If you absolutely intend to flare the car, then buy the wheels/tires to fit that setup. Scottie

No one can ever scoff at a claim of 725hp on the dyno but it seems they never tell you how the power was measured. The performance indicates that power to be at the flywheel. Tonight, Cal Hartline, one of the local GN gurus, drove his fully loaded GN with a/c on over from Melbourne to Orlando for some shakedown runs. 10.40 @ 137 in a 3600lb car is about 715hp at the wheels and about 890hp at the flywheel (80% factor). He plans to drive it up to the GN-fest in Bowling Green, again. BTW, the car purrs at idle and has a slight growl THROUGH THE MUFFLERS at WOT. Heck, with that thing in my Z I could call out Ron, hehe. Someone bust my bubble, please. Scottie

Fairlady 327, here is my $.02. First the cooling. You did not say what setup you have now so it is difficult to know what to recommend. The setup recommended by JTR works. I also like the 24x19 Griffin which you can get from Summit for $181. With a good 16" fan, it looks good and works. You said you do 3000RPMs at 75mph? You mean 55mph right? You would be doing 75mph at 3000 with the 5-speed. If you are looking for a combination to give good acceleration and highway cruising, then the 4.11 might not be the right choice. You need to look at overall ratio (final drive x tranny ratio) not just the final drive. I dont have all the numbers handy, but a 5-spd/3.70 combo would probably have the same or stronger overall ratio in 1st and 2nd than the 4.11/Muncie combo and give great cruising and mileage in 4th and 5th. ------------------ Scottie 71 240GN-Z http://members.xoom.com/Turbo240Z/scotties240zt.htm

Ron, with 2710lbs, the numbers are 890hp at the wheels and 1113hp at the flywheel using the 80% rule. In either case, those numbers broke my calculator, hehe. Scottie

Ron, I dont know what your car weighs, but I guessed at 2600lbs with you in it and came up with 854hp at the wheels. If you apply the 80% rule that's 1068hp at the flywheel. BTW, I saw a Z-car at Lakeland Dragstrip (FL) Saturday night. I was in line and he was at the lights. It was purple and sounded like a big block. Did not hear his time or see the car for the rest of the night. Do you know of this car? Scottie

Ron, I checked out that site with the HP calculator and IMO, any formula that calculates HP and does not factor trapspeed is not going to be very accurate. MPH is the true indicator of HP and I think the following is a much more accurate formula and the HP result is at the wheels: (MPH squared / ET) * (weight with driver / 1000) / 9.1 yesterday I ran 12.41 @ 114.7 and my car weighs 2750 and the HP result is 320 at the wheels. I know I lost .5 on the ET because of the launch and if I changed the ET to 11.91, the HP would jump 13. However, if I increased the MPH by 5, the HP would jump 29. Perfect example of why this is more accurate is that you can reduce your ET dramatically by installing a very low diff ratio and not a single increase in HP. However, the only thing that will increase MPH is HP. Scottie

Z-D, there are no kits for the GN swap so you will have to make your own pads for the motor mounts. Once you get the mounts done, then you can use the JTR trans mount, and have a driveshaft made. As for the T56, I can make some inquiries. I know you can fit a manual, just dont know which ones. To be honest, I had 2nd thoughts going into the swap about using the slushbox, but after driving the car for a couple of months and running it at the track, there is no looking back. The auto trans was a dream running down the strip and I cannot wait to start using the transbrake and launching with lots of boost. Having done a Scarab, JTR and now the GN, the GN is no more difficult except for making the mounts. The front of engine is about in the same location because you need room at the rear to route the downpipe. Unfortunately my mount pads were custom made and welded onto the crossmember, else I would make a copy of them. I dont want to get into a V-8 vs V-6 debate, but IMO I think the V-6 has more HP potential and better driveability when you get up in the 600+hp range. However, I would never turn my back on an LS-1/6-spd Scottie

John, I agree with you but I dont plan on making the investment for a 700hp GN. Instead my goal is mid-10s with a bigger turbo and basic bolt-ons. Of course that is what I say now, hehe. At the moment the car is not ready for hard blasts off the line because I still do not have a way to strap down the engine. However, I was itching to know what it would do and ran it this weekend. To baseline everyone, the car weighs 2,750lbs with me in it and the engine and turbo is stock but with slightly larger injectors, 3" DP and mandrel exhaust, front mount NPR I/C and a 62mm TB, up from 57mm, 3.90 welded R200 and 245 street tires. Again, your basic bolt-ons. Saturday night I ran at the 1/8-mile track with a 93 octane street chip and 17psi boost. On the 1st pass I tried to brake rev and the car crept and tripped the lights resulting in a 4.4 60' and 10.38 ET but 95mph!! 2nd run I just held the brake, eased off the line and waited for the boost resulting in a 2.17 60' and 8.18 @ 91.1mph. I cut a 1.74 60' with the L28/5-spd and if I could have matched that, the 1/8-mile ETs would have been about 7.72. Woulda, coulda. Sunday I ran the 1/4-mile and it was 95 in the blazing sun compared to 80 the night before. I installed the 108-octane race chip and had high hopes of seeing at least a .5 improvement. Instead, the car ran 102mph in the 1/4-mile, missing badly on the top-end. I put the street chip back and ran 12.41 @ 114.7 with a 2.19 60' and 1/8-mile of 8.18 @ 91.9mph. Despite the heat, the car was consistent with the night before and picked up 23mph in the 2nd half. Looks like I might have a bad race chip. My 60' was about .5 slower than with the Nissan engine and when I get the engine strapped down and start using the transbrake and launching with about 8+psi, it should get interesting. I feel the car could have run 11.9s if I was able to launch it hard and with a good race chip, 23psi boost and sticky tires, it should really haul and make the mid-10s goal look attainable. I feel good about the car's potential considering that was the 1st time on the strip with the GN engine and absolutely no power tuning done. I have heard of guys squeezing 400hp with the stock turbo and not even removing the valve covers. John, BTW, I love pulling up to the line and have people wonderif my car is running. Frog, sounds like you had a bad turbo experience. With the Nissan L28T I ran 17psi boost with the stock t3 turbo and 110-octane and ran 111mph with no detonation. Scottie

Problem Solved!!! Now time will tell. I looked at the GN wiring and saw it had a wire directly from the alternator to the battery and wired it up that way. I can only imagine that the big white wire that goes to starter is not connected to anything. Locutus, I feel your pain when I look at the wiring schematic for a late 280Z. Considering I dont have a/c, radio or any amenities, that painless wiring kit is beginning to look good. The factory fuse box is a disaster and I have bypassed it twice. Scottie

I do have the single-wire alt and that is exactly how I have it wired. My problem is that the white/red wire leaves the alternator with 13.7 but that voltage never gets to the battery. I looked at the GN wiring and they have a 10-guage wire directly from the alt to the battery terminal, so I plan on doing that today. After studying the 71Z wiring diagram for another 2 hours, I now see that the battery appears to get its connection from the alternator through the external voltage regulator, then the starter. I eliminated the external regulator and it is possible the wire from the regulator somehow was not reconnected. Slowly but surely I find myself wiring around the original 29-yr old harness. DEMONS, be gone from my Z-car Scottie

I am having the darndest time trying to figure this out and am about to hurt this car. I have an 87 vintage alernator with the single brown wire to excite the alternator. The original white/red wire is connected to the BATT terminal of the alternator. Prior to today the brown wire was connected off the ignition circuit. I get 13.7+V at the alternator but the battery is not charging and has drained down several times and this is the 2nd Die-Hard since this started. When the battery was fully charged it checked out OK. Up to the point of the white/red wire coming through the firewall, it checks out at 13.68+V but then everything after that is 12.6 or less, including the fuse box, cluster switches, solenoid and starter. This evening I trickled charged the battery up to 12.68 and had 13.71 at the alternator. Drove for 30 mins and had 12.33 at the battery. Spent the next hour with the car off and on trying to trace problem. Decided to get bold (desperate?) and run wire from alternator directly to the fuse box. Temporarily connected alligator clip and went to crank it and it was stone dead. Fired up with a jump start but I go discouraged and called it a night. Can someone PLEASE explain to me how the circuit flows from the alternator to the battery. Somewhere after the white/red wire enters the car I am losing voltage. I need to know where I could possibly be losing voltage. I have a Clymer but I am beginning not to trust it. E.g., in the harness I can see the white/red wire covered in black plastic but there is also a fat white wire in that cluster that is no where in the wiring diagram. I really need to fix this problem and I would love to run the car this weekend. TIA, Scottie

Scott, I had a high-efficiency 3-core early style radiator and even with a 10" & 12" fans it could not cool the GN in 85* weather with a 160* thermostat. It probably did not help that I have an Isuzu NPR I/C, oil cooler and B&M trans cooler ALL in front of the radiator. Luckily I found someone on Zcar.com to buy it and I bought a 24"x19" Griffin from Summit, $188 to my door. So far one of the best investments made in this project. Not only does it look good, but with a shrouded 16" fan from the junkyard, the engine stays pegged at 178-180*. Today I put a racing stripe in my shorts when out of frustration with electrical problems, I laid into it from 60mph and stayed in it just short of burying the speedo which was probably a corrected 140mph with the 3.90 gearing. It happened so quick and the Z did not exactly feel stable at that speed. That was one scary blast and I will not do that again. Said all of that to tell you that the water temp SHOT up to 188* and was back to normal within a few minutes. It was 99* today in Orlando!! The JTR radiator works because that is what I had in my V-8 Z, but if you can sell the 280ZX rad and anything thing else, the Griffin, IMO, is a good or better alternative. You might get away with the stock rad and a reaaly good fan but hate to see you have to switch later. Scottie

I know this is not the correct category to post this but I need to get some help quick and I know most of the V-8s are using the same system. My alternator does not appear to be charging. It is the single wire GM unit used in the 87 GN. I have the original Z 10-guage white/red wire connected to the batt terminal and the single brown wire from the alternator used as a tickler gets its source from a wire off the ignition circuit. That wire is run through a bulb which lights up when the key is on and goes off when the engine is running. Thats my low-budget idiot light (how's that for an oxymoron!). Test light at the alternator indicates there is current. I have already killed one Die Hard (sic!) which Sears reluctantly replaced. They indicated the alternator was not charging and I scoffed at them because the alternator was brand new replaced only days previously. Now the new battery has run down twice and my data logger indicates the battery voltage at 11.9-12.1. How do you guys have your single-wire alternator hooked up? BTW, few days ago I ran into the dreaded GM starter heat-soak problem. After letting the engine cool down for 30 mins it would crank right up. I replaced the solenoid and wrapped it and the starter with some heat shield material. Went to fire it up and NADA, just like when I had the heat-soak. I jump-started the car and vroom. I do believe I had a heat-soak problem but I also think the battery was run down and made it worse. Scottie

Pete, somewhere in this thread I missed exactly what the design for the adaptor is. I am the person who made the adaptor that is welded to the 280Z companion flange and I guess I am confused by your concern. IMO, a welded unit is stronger than a bolted one and there is less chance that a weld will come apart than bolts coming loose or shearing. How many times have I heard that 2 components welded together can actually be stronger than a single component. If we should be concerned about welds, then folks like Ron Jones should be terrified that everything forward of his firewall is held together by welds . The R-200/CV combo is incredibly strong, despite my LSD disintegrating . We have a 300ZXT here in Orlando that ran 10.0 @ 140 with a full-body weighing in at 3250lbs. Do the math and thats 700hp AT THE WHEELS!! He runs a stock 5-spd, 11.5" ET Streets, stock 300ZX suspension and axles. He has broken several stub axles at the base of the splines but never a CV halfshaft or Diff. I must tell you that he developed a technique of slipping the clutch off the line and when he does not, is when he snaps the stub axles. That is an extreme case but an indication of how far you can go with the stock components. And, note that I said 700hp at the wheels. I think there is a lot there with stock components and ET Streets before making the leap to a solid axle and slicks. The one problem is being lucky enough to find used components that are not already thrashed. Scottie

Now that I have the car back, if my job will let me stay put in town for awhile I can find and fix this low-speed "vibration". With any luck the car will make its debut in about 2 weekends. I dont want to race it in case the vibration is a balance problem. Scottie

The machine shop just completed modifications to my 4-pt bolt-in rollbar. The rollbar was removed, the bolt-in pads expanded to 6"x6" and the rollbar welded in. After it was welded, they added 2 sidebars with a swingout on the drivers. These mods were done for the requirement track safety and my own piece of mind. First thing I noticed was that the doors now close with a "thud". You can feel the extra stiffness, which does not say much for the rigidity of a stock Z chassis, hehe. Scottie Here is the rollbar just before the bolt-in pads were modified. Here you see the sidebars with the drivers side swingout locked in place. Note the pin towards the low side of the sidebar and the pivot point towards the high side. Here you see the pin removed and the sidebar swung out for getting my big butt in and out.

Mike, they are being custom made by a local shop and is part of a big job so I cannot even say what the sidebars are costing. What I can tell you is that I am paying $425 for the following: - Remove 4-pt rollbar, cut off bolt-in pads and weld 6"x6" pads to the 4-bars - Weld modified rollbar in car with pads on inner fenderwell properly shaped - Make and weld in sidebars with a swingout on the drivers side. The swingout will actually be done tomorrow after I see the job and decide if I actually it or sacrifice some ingress/egress comfort for the extra chassis stiffness - Make seat brackets to fit Pulsar seats. IMO, a pretty good price but nothing to compare to. Scottie