johnc

This has been a know problem for 25 years and has a number of good solutions. Talk with your rebuilder. If he doesn't know how to fix it, then contact Andy Craig at Dandos in the bay area.

Yup, that's it.

Another meaningless bench racing discussion. There's so much more to how quickly an engine gains rpm then just displacement. These four items have the greatest affect on the "zingability" of an engine: Reciprocating weight Moment of inertia Internal friction Pumping losses Then, putting the engine into a car adds a huge number of other variables like: Gearing Driveline MOI Driveline friction Driveline alignment Wheel weight and MOI Tire traction I guess if you use the "everything else being" equal logic crutch, then you could possibly construct a flimsy arguement about how displacement affects how quickly an engine can gain rpm. But why? What's the point?

The diameter was a guess on my part. Just make sure the ID is equal to the ID of the MAF. Remember, intake and exhaust velocity is more important then any tube diameter.

The stock cam is the most emissions friendly one. From the 270 degree spec in your post it sounds like you have the L7 cam. Try the 13001-N3626 cam from Nissan Motorsports (434" lift and 256 duration.) Its commonly referred to as the "Slalom" cam and it should work well with the mild build you're planning. Iridium plugs ar a waste of money, you don't need JE or Ross pistons for the build you're planning (stock pistons are plenty strong enough), go with a Crane ignition over the MSD, and the Nissan 5 speed is plenty strong enough. If you've had to tear the trans down 3 times in 5 years either you're destroying it with your driving or the rebuilder doesn't know what they are doing. SCCA ITS racers can go two to three years on a trans rebuild.

Buy two. You're bound to screw up the first one.

The F54 is an L28 block. For the mild-buildup you're doing, just use whatever L28 block you have. Expect about 200hp at the crank depending on how well you can get that Holley tuned.

Buy about 12" of 2.250" OD aluminum tube, an aluminum mandrel U bend of the same OD, some silicone hose, hose clamps, and start cutting and welding.

As of early September, Bob Endicott's 2001 SCCA T1 S2K has over 100K miles and it competed nationally road racing for 18 months and his wife has been driving it on the street and autocrossing the car. As far as I know the engine's never been apart.

Uuuhhhh, those are not hubs, they a brake hats if I'm not mistaken. Hubs are where the bearings are and what the hats bolt to.

No, just read the above in one of Carroll Smith's books. Also, my nephew, during his BUDS training watched one of the teams get busted for filling their raft with helium. It kept loosing the helium over the course of the day and the instructors made them refill the it using lung power only - while carrying it on their heads - running through sand.

Doesn't work. The helium molecule seeps through the tire carcass and you loose about 10 psi per hour.

Probably not. There's too much welding involved in the installation, including notching the crossmemeber. I can't oversee the quality of the work but I could still be held liable for something going wrong. If its for a track only car - not registered for the street, not insured, and the customer signs a disclaimer then I might consider making and selling the mounts. Maybe.

I'm working with someone on an SR20DET conversion now and they keep saying the same thing. And I keep asking, "Where's the air going to go after it comes through the front of the car?" The engine compartment aero of the early Z is designed to exhaust radiator airflow down immediately after the radiator. A V-mount won't change that basic airflow pattern so the radiator (which is traditionally on the bottom of a V-mount) will receive most of the air flow and the intercooler will be stuck in a dead air zone near the hood. The other alternative is to belly pan the engine compartment, put a big rectangular hole in the hood with a forward lip, and exhaust all the air-flow up (like an NSX front hood). That will require a front air dam and splitter plus the belly pan and the internal engine bay ducting. FYI... I was able to get the SR20DET engine mounted behind the front crossmember, which doesn't appear to be the case in the pictures I've seen so far.

You'll need new shocks with longer shafts and longer springs to keep front suspension geometry correct. Probably the same in the rear to keep the control arms pointing slightly down at rest ride height.

A 1.75" ID tube (~44mm) will flow enough CFM to work on a 500 horsepower engine. Look at the intake restrictors required on ALMS and FIA Le Mans LMP675 engines. Size isn't that important when it comes to intake flow. Velocity is an order of magnitude more important then tube cross section.

Huh?

SCCA doesn't give you a wall thickness break anymore for 4130 steel. Its gotta be just as thick as DOM (.120 wall for our 240Z weights) so there's no reason to pay the extra money for 4130. My roll bar is .095 4130 and .065 wall 4340 and was built back in 1995 when there was a break in wall thickness for using CroMo.

I think we have a terminology issue. Wheel rate as I define it is the spring rate at the wheel. Its the actual spring rate divided by the lever arm (the distance from the spring to the wheel center). On a strut suspension, wheel rate is almost identical to actual spring rate. On a control arm suspension the wheel rate can be 1/2 or even less of the actual spring rate. Weight distribution doesn't affect wheel rate.

Designing the head is an engineering project, making it is a machining project. Try to find a mechanical engineering student who needs a project and maybe you guys can work together. Expect it to take a couple years to complete with all the other coursework you'll have. Regarding the marketability of the head, find a marketing student and add them to your project team. FYI... the entire market for that head is less then 20 worldwide assuming $10K pricing and maybe 40 if you can get the price down to $5K. The head would not be legal for any sanctioned road racing class here in the US and that's where the people are that spend tens of thousands of dollars on L6 engines.

He's a ghynecologist. Those are the stirrups he has women put their legs in when he's doing an exam. Notice the styrofoam cup blocking the front wheel. The car needs a parking brake and must be really light.

There's some debate about which block (N42 or F54) is actually stronger. Here's the information I've been able to accumulate over the years. The early N42 blocks (1975, 1976 I think) had the highest nickel content of all the L6 blocks and are stronger from a metallurgical standpoint. Nissan felt that the later blocks with a lower nickel content needed some design changes to handle the additional combustion pressures in a turbo application so the added the bracing between the cylinders. The nickel content change was a cost consideration. The early N42 blocks are more dimensionally stable (the cylinders stay rounder) then the F54 blocks if your overbore is .040 or less. The F54 blocks are more dimensionally stable at larger (stroker size) overbores. A friend (Tom Smith) who worked at Electramotive in the late 1980s and early 1990s said that the F54 was developed to handle the high turbo horsepower requirements for IMSA racing in the 1980s, although they did have ring sealing problems traceable to dimensional changes in the cylinder bores at high temps (they never overbored the blocks). He also said they blow up a lot of engines before they found the right combination that would last a full race. That's all the rumors, innuendo, etc. that I've heard about the block differences.

The SCCA, NASA, and other United States road racing sanctioning bodies all specify ERW or DOM tubing with DOM (Drawn Over Mandrel) preferred. Schedule 40 pipe is specifically excluded (brittleness) and they've stopped grandfathering older race cars that used it.

If you're building a sleeper, run the QJet. Way back in the late 1970s I had John Lingenfelter (yes, the same guy) blue print an 800CFM QJet for my 1966 455 GTO. The car run 13.2s all day, every day with the QJet, stock air cleaner, cast iron intake manifold, cast iron exhaust manifolds, etc. and I won lots of money on the street with that car. Told everyone that car had a 389 and no one ever questioned that statement.

Mostly hard braking. The chassis will oscillate a little leading to some uncertainty about which end is going to lock up. You always want the fronts to lock up just a micro-second before the rears. With a pitch oscillation you might have the rears locking up first in corner A and the fronts locking up first in corner B. Then on lap two the situation may reverse. It depends on the track, the bumps, and driver input. You may also see it in a fast sweeper where the chassis is upset by a bump and starts to oscillate a bit. You'll feel the oscillation (and maybe even see it) and the car will feel like it doesn't want to take a set, or maybe it looses the set it took. Some people describe it by saying, "The car is vague, doesn't want to keep a line." Its a subtle problem if you have good shocks, its a scary problem if you have bad shocks.