John Scott

I've had mine way to fast for a short stint. 5800 in 4th .7 overdrive, 3.54 gears. Above 160+! Only for a few moments. Didn't take long and had plenty left.Scarey! I'm gaining a little more sense as I get older. I don't want to be a test pilot again unless I have a proven body/chassis system. Really good rubber is a must, too. It boils down to: Just because you can doesn't mean you should! JS [This message has been edited by John Scott (edited July 12, 2000).]

Datsunlover, Yeah this site caters to Z fanatics, but there is a great amount of information here you can apply to your project. We're a pretty diverse group, but all have the common binding element of owning, or hoping to own a Z. I'd say your welcome to learn from our projects. JS [This message has been edited by John Scott (edited July 13, 2000).]

Stan I vote for the instant gratification factor. ATI PROCHARGER!! Make sure you get a boost regulated fuel regulator. I use the Mallory with their 140 pump. Set the idel psi to about 4-5. Also I can fill you in on modifying the carb. Simple to do. 12 rib if you get greedy for more power and later bigger badder projects. Whats your compression? Man this thing will fly!! JS

4.3? Whats that? I'd love to see the build sheet on that motor!. The 4.3 is a great motor. The 60 degree offers some really interesting possibilities too. So, keep your jobs, its going to take some cash to build any of these giant slayers. JS

Yep, time to call ATI. Catch them early while the tech guys are fresh because they get a ton of calls in a day. 913-338-2886. I'd bet the 600b will give you all the boost you can use. See what they say. JS

ZD, you could theoretically run two prochargers, but why? Remember these boost linearly with rpms. They make compressors that can make 12-1500 hp. I guess the reasoning with twin turbos is that you can run smaller housings with faster spooling. ?? JS

If only! There's no end to the insanity! JS

Amen! BLKMGK, I had a friend who kept cranking down on his wastegate until he was pushing 20+ No improvement in performance! Some superchargers are not able to push a certain CFM. Boost #s are only a poor reference of potential power. A roots blower can make tons of boost, but mostly its just expanded air due to the terrible adiabatic efficiency of the units. Can you say race gas! Just like denser intercooled boost will be a lower # but produce higher hp. A good flowing engine will do the same. ATI is suprised my boost #s are lower than, lets say a 4.6 mustang, with the same drives. Head work, Proflow valves, big cam, etc. allow me to use up more boost. Mine makes boost unloaded. How much are you talking @ what rpm? Now... about those 4.3 Brodix heads and crossram! BTW you are in for one hell of a ride with that 351! Looking for passengers? JS

Mike, I wouldn't worry about your reading @ idle. About where mine is after it gets hot. Use to bug me, but always have great pressure at speed. I agree with the 10 psi/1000 rule. What kind of oil do you run? I get a little more pressure with the 20-50 racing Vavoline. Got to warm up slow so you don't peg the guage and blow the filter. Also harder on the dist gear I've heard. All the new cars seem to run the 5-30. Looks like water to me! JS

I wouldn't put a whole product line down on one incident. If Prochargers were shelling left and right then you would have an argument. Granted they're not putting a lot of effort into making them pretty. I seriously wonder if there wasn't a problem with the individual unit or his installation. 15 psi should have been nothing for a 600B. (Unless he had the straight P600. If he over reved the thing then that would explain it too.) Was it a Billet impeller? I'd like to hear more facts about what happened to this unit. Another Question: How much is a Vortech S trim? How much boost is it capable of? Just curious. JS [This message has been edited by John Scott (edited July 03, 2000).] [This message has been edited by John Scott (edited July 03, 2000).]

Spin one axle (make sure the other remains still) 2 revolutions. Count the # of turns the pinion flange makes. 3 1/2 will be a 3.54. almost 4 will be a 3.90. JS

Thank you Scottie! Just the info I need. I'm inclined, as is my budget to stay with the air to air. If I were more dedicated to the 1/4 mi I'd probably save for the A/W. Good info! Now...what is Cartech's #? JS [This message has been edited by John Scott (edited July 03, 2000).]

Spence, According to ATI, your 8:1 comp. will let you run about 14 psi MAX w/o intercooling. Since you are going to intercool it you will have a "buffer" to around 22 psi. These would be max on pump gas. Z.D. As Ron suggested in an earlier post,1st get your crank magnafluxed. This will be the starting point for a good or trashed crank. Deburring helps eliminate stress risers, check for straightness, find a really good machinist to prepare it to nominal specs. Cross drill it for high rpm oiling. Lead in grooves can be put in journals if you'll see sustained 7500+ The Chev. Power manual has this in the crankshaft prep. section. Get a really good oil pump that supplies about 65-80 psi at operating speeds. Make sure your pick up tube is tack welded to the pump and sits just off the pan bottom. I had all this done, but the lead in grooves. I didn't plan on too many 7000+ ventures. My rods were prepared as to chevy manual with the good ARP fasteners. Polished, profiled, shot peened, maged, etc. Couldn't afford the raw cast forged crank. But the stock with 4bolt upgrade is pretty strong. 7000 isn't that high for a small V6. A good bottom end will help all the other facors of high loads on the ricip. assem. Your valve train has lots to do with potential RPMs. Looks like the 60 degree has avil. 4 bolts. If there is a forged crank I'm sure it would be money well spent. Some good reading in the Chev. power catalog. Also to note, make sure your heads and deck surface are dead flat and use premium head gaskets. High boosts are notorious for blowing these. I had one bad experience, but had heads resurfaced and went to the high $$ gaskets. Good for years now. Lastley, spend the extra for positive seals on your valve stems(guides) The stock umbrella wiper rings won't cut it. Usually requires guide machining, but keeps detonating oil out of the chambers. This is bad for boosted engines. The 60 degree has my interest pumped up now too. sounds like a winning combo. JS [This message has been edited by John Scott (edited July 03, 2000).]

BLKMGK, you mention a spring tensioner for the procharger. I hate setting mine in relation to the belt dust. Is this for the cogged belt only? Does it have enough tension for the ribbed belt design. $$? Scottie, You've played with different intercoolers. What fits well into the Z front end w/o hacking up metal. The 3 row ATI is too big unless I move my radiator inboard and place intercooler there. Max efficiency, hp potential spoken here, please. JS

BLKMGK's comments are good about the cogged belt issue. Not for the street. The flywheel effect of the impeller needs the slippage of a ribbed belt when shutting off at high RPMs. Good for race units, roots type blowers. The P600B will handle/flow, as ATI claims up to 800hp. This of course is starting with a healthy V8. I can attest to the 600Bs reliability. Its worked flawlessly for 5 abusive years. If you want good HP #s from a V6 you'll need much more than the 10 lbs of boost that BLKMGK runs. 10 psi from a big 1200 compressor can make lots of hp. (fire hose, garden hose comparison) For the 3.4, or 4.3 for that matter, you won't start getting good hp (in my opinion) until you reach the 14-15 +psi range. This gives you the roughly 100% increase in HP. A low compression V6 doesn't make much hp at any rpms. For high boost you have to have forged pistons @ about $37.00 a piece.(TRW). Much over this and you need intercooling. Consider this a necessity in your build sheet. Hot air will not make hp, just high boost #s. Also get the proflo relief valve. This will let of pressure when you don't need it. Shutting off at high rpm can be hard on the compressor, bend throttle shafts, and further heat up the air mixture. Also figure on a custom grind cam. Off the shelf "performance" cams will have too tight lobe seperation angles resulting in high cylinder pressures, i.e. detonation. 114 degree is about perfect for the V6. This also gives much better top end, a feature you need with small displacement supercharging. Spend lots of $$ on the bottom end of the engine. Oiling/rods/crankshaft prep/balancing/etc. You're cranking v8 like #s through a smaller assembly. As you can see there is more $$ involved than just buying a supercharger and bolting it on. For those of you who haven't driven in a high boost v6 you have a strong but not overwhelming launch, (good for light Zs) say above 2000 rpm, then its explosive to redline. Get a rev limiter! There will be no watching the tach/boost guage until you get the hang of it. I still can't in 1st! Expect a peaky hp/ torque curve. You have to pick your gears a little more carefully when engaging in road wars. Putzing around below boost is easy on components and gets GREAT milage. 25+. Passes emmissions easily. I think it makes driving more interesting. Once again I'll say for endless $$ supply a turbo/twin T would be the superior hp maker, but the supercharger is still a great power adder. When one of you guys puts a 14 psi unit on a big v8, invite me to the party! JS

BLKMGK, Spring tensioner? I'd like to hear more? I'm tired of guessing the belt tension with only belt dust as a reference. Cogs are out in my opinion too. Must be perfectly aligned, harder on parts. Expensive! Need a bypass as well. I do run the big proflo. I didn't want to bend the throttle blades, and didn't like the idea of "stacking up" air in the compressor.. Sounds cool letting off a high rpm pass. Carbureted prochargers work great! Not as effecient as EFI, but very few if any complaints otherwise. Drives like any other good holley except instant starts year 'round w/o choke. That 1200 must push some serious HP! What are you running it on? JS

Mark, ask for nothing less than the P600B. And do your future bearings a favor and opt for the 12 rib pulleys! John (wishing he had gone with the 12 rib) Scott

Is he using the ATI three row? If so how did he get it to fit? If another brand, which? D1 is physically same size as the P600B. Higher max RPM 65,000! How much more does it flow? Edelbrock FI? Get this guy over to a keyboard and fill us in. You've stirred up a lot of interest here. JS

Federal Mogul says they discontinued the main bearings for the 4.3! If this is the case then they discontinued the whole line of small block Chevys. The mains are the same! Apparently its not cost effective to pull one bearing out of a box and call it a 4.3 set. Weird! I had to order the 350 set. Showed up this week. Nice looking units with a 3/4 oiling groove. Rod bearings are to be shipped this week as well. I have to relocate my 1/2" return line for the T56 swap and then its ready to go. I've done the "ritual beating", had 28 years of crud fall into my eyes, and hit my hand a few times. Loud obscenities could be heard throughout the neighborhood. @#$%in' piece of @#$%, !@# of a )*&^! "Oh, John's working on the Z again!" Had a nice long talk with FastFrog. He's convinced me to re-evaluate my blower bracing. Also got me excited about FI again. @#$%! Frog! Its hard enough to concentrate on the transmission and bearings w/o you stirring up my wish list again! Its great to talk to another enthusiast. JS [This message has been edited by John Scott (edited July 01, 2000).]

Tom, If you get serious about the 377 project and want a really good set of Brodix heads, my neighbor is selling his. He swears by his 377 combo and regularly whips the pants off many same weight cars with huge cubic inches. Rarely sees over 7000 rpm. There is much more than just displacement going on with this engine combo to make big hp. If you want, and my neighbor willing, I'd give you his # and you could discuss it more with someone who runs one. With 450 hp your are going to have severe traction issues. It doesn't take much to spin the tires on a light Z. JS [This message has been edited by John Scott (edited July 01, 2000).]

Mark, I'm all for the idea! Any time you can save weight you are making hp. There's a lot of potential in the 60 degree. More room with the narrower banks for supercharging, headers etc. Keep us posted. JS

I also use the method suggested by Frog. Make sure your cam is on the base circle when you are adjusting. Adjust the intake when the exhaust is just opening. Adjust the exhaust when the intake just starts to close. Its easy to add preload with just finger tension on the nut so spin the push rod while you sneak up on the 0 lash. Yes you can still spin it with considerable preload so feel carefully. (especially if you haven't had the lifters "pumped up") When it just starts to "grab" the push rod, your there. You'll hear everything from 1/4 turn to a full turn. I'd stick to the 3/4 to 1 turn. Hold the nut in place with a wrench and tighten your setting with the allen/hex lock. Snug it up pretty good but don't over tighten. I set mine to 3/4 and good to 7000+rpm. Also, you have your guide plates and hardened pushrods? Non hardened will ruin quickly spreading metal pieces into the oil. Don't want to hurt those nice heads! JS

Interesting! I tried a set of AC Rapidfires a couple of years ago. Much quicker starts and REALLY cleaned up the idle and off line stumbles. I was sold. Only plug I'll use in my Z. Electrode technology has been ignored for many years. I bet we see even better designs in the near future. JS

Takman57, you have my attention on the coatings. What would this do for a forged piston top? Get as technical as you can. I'd like to know how they work. How applied, materials, the benefits for high boost? Could they ever come off? More resistant to detonat. damage? JS

BLKMGK, There aren't any stupid ideas here. If you've got a mind set on something go for it. Its going to be YOUR ride so make it the way that gives you the most satisfaction. Put the biggest damn exhaust you can find/fit. Let some V8 thunder put the rice rockets to shame. JS