Scottie-GNZ

Sit tight folks, I have an annoucement to make a little later.

Coming along nicely Mike.

Datto, 10.5 to be exact. The SVO injs require a mod so check my L28T site to get that. http://www.zdriver.com/members/scottiegnz/scotties240zt.htm

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.

This debate has been going on for a long time and I have yet to hear what seems to be a logical explanation. However, here is another way to look at it. Take a look at many upgraded turbos, including mine rated for 580hp, and the compressor outlet has a 2" od, repeat OD. on the other end, we are scrambling to installing 60mm or larger TBs . I have a 2" to 2.25" hose on the compressor with a 2.25 pipe to the I/C where it steps up to 2.5" and 2.5" from the I/C to a 62mm TB.

Man, you got the itch to get going dont you Patience, I am working on it. Looks like we have the minimum, so all who are interested, please send me an email with how many you want so I know exactly what the total is.

My 75 JTR V-8 had the cable and it would always loosen up. I tried solid and took them out immediately. That is when I came up with my own solution.

The issue is not whether or not the 3.8L can spin to 6K, but stock, that would be way out of the powerband. With what you are doing, the right cam upgrade, and some work on the heads, it will easily make HP up to 6K. Despite all the HP this engine can make, the stock heads are simply horrible. Some mild porting, especially the bowls and port matching, does wonders. The 1st-gen RX-7s came with 3.90 and 4.10. However, they should be CHEAP and if you target the ones with disc brakes they should have an LSD. Once you get one, then look for a 82-84 diesel-powered B2000/Courier as they came with 3.31 and I am sure the yard will PAY YOU to get that outta there . You then swap the 3.31 R&P into the RX-7 carrier and bingo Those Japanese truck rears are incredible. Carlos, my buddy and the SDS distributor, has a 525RWHP RX-3, turbo-13B and a 6000RPM stall on a P-Glide and he has been running a welded 3.90 from a Datsun P'up for years. Oh yeah, best to date - 9.59 @ 139 . [ July 26, 2001: Message edited by: Scottie-GNZ ]

Yes, I have done it and it is a fairly common no-buck mod in the DSM world. HOWEVER, there are lots of caveats: - Do you know how much of an increase you want and what it will get you? - If you go too far, there is no going back - Do you have an accurate fuel pressure gauge? Do not attempt to do it w/o one - If you are running the stock pump, make sure you do not exceed its capacity. I forgot what it is but TimZ posted the number recently so do a search - Do it in small increments. You might have to de-install/install the FPR a couple of times until you get it where you want it - If you go too far there is no going back. In case you do not know the formula for calculating the flow rate, here it is: Divide the new pressure by the old pressure, take the square root of that number and multiply it by the inj flow. Of course you must know the inj flow rate and what pressure it was rated at. E.g., I believe (could be wrong) that the stock turbo inj is rated at 260cc @ 36#. If you raised the fuel pressure to 42#, the injs are then capable of flowing 280+cc. Make sure you set the fuel pressure at idle with the vacuum line off. Go find TimZ's post and make sure the new pressure + max boost does not exceed the number he specified. REMEMBER, IF YOU ARE RUNNING STOCK INJS, THEY COULD BE AS MUCH AS 20 YRS OLD. Good luck.

Let me see if I can help address some of the questions. With the adaptor in place, I jacked up the control arm to the point where I felt the CV had the farthest travel in towards the diff and at that point I pried the CV and there was still a little compression left in them. I wonder if anyone is going to put their Z-car under more extreme squatting conditions that I have put mine? I would say that is "proven" . Do not know anything about Mike's adjustable rear control arm, but if you can make such extreme inwards adjustment it would be an issue for any axle and I would also be concerned about the alignment. My adaptor has the appropriate sized hole in the middle of it accomodate working with the big stub axle nut AND to fit the niple at the end of the CV in. Therefore the nipple on the CV had no influence on the thickness of my adaptor. 240Z and 280Z companion flanges physically look the same but you can slip a 280Z companion flange over the splines of a 240Z stub axle without the touching. When stub axles break, they break at the base of the splines so you want to use the thicker one if possible. There is no core charge. Where does that leave the folks who prefer and want the bolt-on?

Unless you have done work to the 3.8, you are wasting time revving it pass 5200, so the mph numbers for that gearing combo will be much lower. My car weighs in at 2820# (w/me) and has about 410RWHP which is a tad less than 6.9lbs/hp. With your 2000# you only need 300RWHP to match that. I do not know if your car will accelerate as quickly as mine, but for this discussion, lets say it is a tad slower. My 0-60 is in the 2.8x sec range and if you redo your numbers you are going to get about 64mph in 3rd. YUP, thats right, under hard acceleration you will have to do a 1-2, 2-3 and get ready for the 3-4 in a tad over 3 secs . You are going to be dealing with some serious acceleration here and unless you have sticky rubber, the torque is going to generate some serious wheelspin which worsens the situation. Not only do you not want to have to shift that fast, but winding up a Buick turbo that quick in the lower gears is not the way to utilize its potential. That is why I am going to a much lower numerical ratio. I know you probably do not want to hear this, but my advice is to find a lower numerical ratio and the tranny with the longest 1st gear.

Mike, I hope I am not misunderstanding your idea, but it sounds exactly like my adaptor design. As I stated before, some folks prefer the bolt-on and some the welded design. Both machine shops require a minimum of 10 and there is not 10 of each, so the focus should be on one design so everyone can have an adaptor. I really do not care which adaptor folks choose but I do not want there to be any misperceptions about mine. I have no burning desire to make and sell adaptors but if folks express an interest, I try to help.

To answer SleeperZ's question, I designed my adaptor specifically to address the binding issue and because I personally preferred an adaptor that was precisely welded than using all those bolts. There seems to be a misunderstanding that my adaptor requires precision welding and that is not so. The current design has a pocket machined in it to fit the companion flange and provide trueness. The welding required is just to hold the companion flange in place. Unfortunately I did not take any pics of the new design. I do not believe there is enough demand to warrant 2 competing designs. Like anything else I have offered to others, this is something I designed for my own use and others saw a need for it. I am not in the parts business and doing this GP is really a royal pain but one I do if others will benefit. I am willing to withdraw my offer to make these adaptors so the forum can focus on one solution from someone who is more geared to supporting it.

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 ]

Pete, will do and I know about budget monies getting tight. Mine is not so much tight as my goals keep changing and speed cost money. My Z started out as a 250+hp L28T that was going to see light road racing and autoX duties . I get a grin everytime I see a post here that says they are just looking for about 250-275hp. Uhhh, yea, RIGHT!

We are close to having the minimum 10. Here is a list of the folks who have expressed interest, to date: Floydd Grissom 78TurboZ Pete KraZ4spd Evan Mike Kelly Z-dreamer Tsumner Vinh Vu

Jim, if you are off a tooth or two, just twisting the distributor probably will not get it correct. I would start over by putting #1 on TDC and repostioning the distributor. I get #1 TDC but putting my finger over the plug hole and turning the engine from the crank while looking for the TDC mark AND watching the action of the rockers just to be sure.

quote Ashe, not sure I went so far as to say that. The GN engine is only available with the TH200R4 automatic. You can convert it to a manual as long you are aware of the gearing. The Buick cars do not make good autocrossers or road racers as they came setup from the factory. Please reread that statement to make sure it is understood, because when Buick made an attempt at improving the suspension in the GNX, it pulled .92G on a skidpad with mid-80s tire technology. Folks who have swapped the GN engine into other cars did it primarily because of the HP/torque potential for drag racing and stuck with the automatic because that was what worked best. [On soapbox] I have long since gotten over the "this is a sports car and it must have a manual gearbox thinking". [Off soapbox]. No reason why the GN engine/automatic cannot work in autoX or road racing, you just need to do more throttle modulation, especially autoXing, to control the explosive rush of power. I just noticed you are in Clermont. Drop me an email tonight and lets get together. MOF, if it stopped raining I plan to test the car tomorrow night. [ July 24, 2001: Message edited by: Scottie-GNZ ]

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.

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.

Yes. I have spoken with Pete several times in the past. I plan to call him today because I need to ask him some questions.

Hey Stony, Mark is not the one building the GN-RX7. The 1.8L was doing fine in the Silvia, enough to go 12.0 @ 119 with lots of wheelspin, then he broke the tranny trying a 7000RPM launch. He pulled the 1.8L, adding new cams and more HP intending to build an all-out drag car with an old 200SX. That went by the wayside. He still has not touched the RB25. He then wanted to turn the 240Z into an ITS car and not sure how that is going because last I heard he bought a bike. Too many options.

I used a stock GN harness and removed what was not needed which ended up being about half of the harness . I am using a VSS from JTR mounted on the speedo connection on the tranny. Getting ready to help my buddy do a Buick turbo/II-gen RX-7 this summer so we will probably be making some parts as we required.

One of the people that James knows that ran the stocker at 17# boost is me. Having a free-flowing exhaust starting from the wastegate was key in reducing backpressure and therefore heat buildup in the turbo. Whatever volume the t3 was moving at 17# was probably extremely hot but that is where an efficient I/C and proper fueling and timing help contribute to the engine making HP at that level. 111mph trapspeed and a gain of 27mph in the 2nd half is certainly proof I was still making good HP. Having said all of that, I would not recommend folks go that route. Spend the $400 to upgrade the t3 or more $$$ for a full-up t3/t04. You will be extremely happy and surprised at the difference. Remember, the best turbo exhaust is no exhaust.

I like it and, like Pete, would love to hear the details.