Drax240z

It isn't bad at all man, do it!!!!!!! There are a few around here allready done, it's a sweet swap and makes tons of sense to me. I'd never put an SR20DET into a Z... and I know the potential of that motor. The severe lack of anything resembling power below 3500rpm is a bit of a turn off for street/autocross duty in my eyes.

Drive shaft flanges, moustache bar, front & rear hubs, brake rotors, exhaust system flanges, yadda-yadda all should be thicker then 1/8" IMHO, but none thicker than 1/4". It depends greatly on the particular material involved however. Forthe majority of fabrication done by 99% of the Z populace, 1/8" is as thick as you need to go though.

Well I made my decision years ago and am happy with it. Either option built well and intelligently will give you some awesome performance, and without breaking the bank too. There are probably over a hundred 12 second Z cars belonging to members of this site, and lots of them representing each engine option. 1) Decide what you want from the car. 2) Search and read a bunch here on how others have accomplished it. 3) Decide on an engine. 4) Research how to get than engine to meet your goals. A piece of cake!

10 feet of 3" pipe is .49 cubic feet.

I'd guesstimate that if you are smoking them up in 3rd without power shifting you are over 300rwhp. Let the bench racing begin!

I'll say!

I still think the S13 240sx with a VG30DE (ie: twin cam, 3.0L, V6, DOHC, from Z32 NA's) would be a nice, well balanced car. Not stupid fast or anything, but it would probably be a really nice driver/autocross car.

They look great to me for the most part. The only things that strike me as a concern are the clearance of the bar over the battary, and the firewall mounting points reinforcement. My battery is quite tall and I don't think that system would work with it. It goes look like it will be quite rigid though! Note: I *really* don't like the way the harness mounts to the strut tower bar when there is a perfectly good roll cage right there. Strikes me as foolish. Not to mention the twist in the passenger side shoulder belts caused by the diagonal bar.

I agree with John, nothing on any street/race car needs to be 1/4" thick than I can think of. 1/8" works really well for the plates. It gives you enough thread left on your upper isolators in order to use the stock stud/lock washer/nuts. As far as the cross bar goes, Pop N Wood's info is on the right track though not entirely accurrate. A solid bar (of equal diameter) will be MUCH stiffer and stronger under all loads you'll see in this application, especially if the bar is bent. However, the trade off is a rather large weight gain. In purely torsional loading (ie: prop shafts, any spinning shafting for that matter) the OD of a round object plays a huge role into the stiffness and strength of the shaft, while the ID plays very little role, this is a place you can get away with hollow shafts all the time. (ie: driveshafts) Because of the combined loading experienced by something like a strut tower bar, a larger diameter hollow tubing will be stiffer FOR A GIVEN WEIGHT, than a smaller diameter solid tubing. In most racing/street situations we are concerned about stiffness vs. weight. If weight is of absolutely no concern, you could go crazy and make a 100lbs strut bar that will be stiffer than my 3lbs unit, but I wouldn't recommend it. Also the law of diminishing returns applies, your 100lbs bar might be only slightly stiffer than a 30lbs bar, in which case is it worth the extra 70lbs? In order to find the optimal material size there is a lot of physical testing that can be done to come up with some hard numbers. Or you can take the easy road and listen to the guys that have a pretty good 'gut' instinct about these things. (many, many members of this board) Last word: Pretty much anything you do to tie the strut towers together will be a NOTICEABLE improvement in chassis stiffness. Even some cheezy lightweight bar (a buddy of mine used one that was less than .5lbs all told, aluminum and 16ga end plates) was a noticeable improvement over nothing. Don't wreck yourself trying to design the perfect strut bar for your car unless you are a) racing, or going into production with it.

dual carbs with K&N's.. are these any good or should i get bigger air filters? Those should be fine. C) header is rusted, surface is very rough (pitting?) can i salvage by sandblasting and using POR 20? It's worth a shot! I've also had decent luck with VHT 1500* paint. D) same with exhaust, but i am scrapping this and getting a custom 2.5" 2.5" works really well on a Z with a header and a cam. Put on a turbo muffler and you should be good to go. E) owner claims the engine revved very fast, thought it might have a lightened flywheel. i was unable to determine but i took pics (will upload soon) Fast compared to what? F) the head is an E88.. which didnt come on '78 280's. owner said head might be shaved a small amount. (i'm thinking if this was a swap, then its definately possible. lightened flywheel is possible too, right?) Hmm, strange. The E88 had smaller valves than the stock N42. Likely it decreased performance from the stock head. Who knows what the engine is though. I'd guess there probably isn't a lightened flywheel though, if someone is going performance decreasing mods. H) when the car was on the lift and i spun the right rear tire forward, the left rear tire spun backward. mechanic said its because i have a limited slip, is this true? That indicates there isn't a clutch/viscous limited slip installed. Some of the planetary styles of LSD will look like an open diff though. None of the early Z's came with LSD's stock. Very, very, very few will have a planetary style LSD installed. I'd wager dollars to donuts you have an open diff. I) since the tranny is being rebuilt, can i put in some shorter gears while i'm at it? if so, how much extra do you think this would cost? Not easily. Tranny rebuild usually include new bearings (~$80 or so for all of them) and new synchros. (~$250 for all of them) Don't forget to add labour. Oh yeah, run a quality synthetic fluid after you get all this done too! Welcome to the site!

How'd you get that to fit in an early Z? I'd be interested in hearing what everyone's opinions are on their current setup as well. Front Rotors: 73 Stock Calipers: 73 Stock Misc: Semi-metallic brake pads Rear Rotors: None Calipers: None Bracket: Stock Backing Plates, drums, organic shoes Master Cylinder Stock 7/8" bore Booster: Stock Brake feel is overall decent. Pedal is firm. Good modulation. Brakes tend to heat up quickly in autocross/mountain driving, but with fresh high temp fluid, fade hasn't ever been a huge issue. Stops from 100mph+ are pretty poor. Braking with R-compound rubber could be stronger overall, but I'm probably still not braking to the stock brakes full potential. The drums are a pain in the butt, requiring constant adjustment... and the bias changes with adjustment. That's the biggest reason I am upgrading.

Pop N Wood got it. The biggest issue I have with the bar on my car is that it has to be completely removed from the car in order to do a valve adjustment. Not a big thing really, but a bit of a pain. You won't be able to do a straight bar on a Z with the L6 in there. At a minimum you will need a gentle curve along the whole bar, or one more abrupt curve over the valve cover. (or multiple bends as john's pictures show, a lot can be learned from what he has done there!) My cross bar actually has 3 bends in it, one at each end, and one slight one just over the valve cover. Not optimal at all for stiffnesss. End plates I'd suggest 1/8" mild steel. Cross bar 1" diamter 0.065" or 0.083" wall mild steel tubing. Removing any flex point is a good idea, but you do have to think about being able to remove the bar easily & access the valve cover, so you might want a more traditional pivoting design. Or you could fab something up that was removable and didn't flex... (which is one of the draws of John's triangulated setup) Fabrication wise it would be a bit more involved though.

"For some reason I can't modulate this toggle switch" If it is an issue though, you might try making your throttle a little more progressive. 315's, LSD, AVS sports... I can only imagine that type of grip! 205's, open, crappy tires... welcome to my traction limited world. Some kind of conspiracy going on here... since when do we get the white stuff before you guys?

Uh... 2 hours and $10? Your bandsaw or angle grinder with a zip disc should make a plate for you in no time. I did use a torch to heat the tubing for the bends, but you could do it with a cut/weld technique without any problems. John makes an extremely good point about letting the loads transfer directly to the chassis. It is very important to minimize the slop between your chassis bracing and chasiss. (ie: oval holes aren't the best!) I've not yet driven in any Datsun that hasn't benfitted HUGELY from extra chassis bracing in the strut tower area, front or rear. It makes a really large difference.

What kind of tires are you running Scott? Sounds good man. We got snow in this neck of the woods last weekend, I'm surprised you're still driving out east!

For 90% of the road going public, good old low carbon (1020) mild steel will work just fine. It's easy to work with, relatively stiff, strong and can be finished many ways. Here are a couple of steel ones I've made in the past month or so. Very simple and easy to make. The first one is on a 510 and allows a straight bar between the towers. (on an non-L20B engined car) The cross bar is 0.065" wall 1" mild steel tubing. The second one I did on my own car more for an experiment than anything, to see just how much difference it made triangulating the strut bar to the firewall. The results: the gains from triangulating to the fire wall over the previous straight bar, were MUCH greater than the gains from going from nothing to a straight bar... Again using my old stand by, 1" 0.065" wall mild steel tubing. I use this stuff all the time. Anyway, the 2nd one is kinda hacked together, it is just a prototype.

Yup been there with no visible damage to the car or suspension parts. I was able to dial it out with eccentric bushings on the rear control arms.

Wow Jon, your experiences correspond exactly oppositely of mine on these. I've used the early 280zx (79-81) 'flange' style sliding calipers on a fair number of cars now. Using early 80's 200sx stuff we've done a couple 510 wagon rear disc conversions using these calipers. Within 6 months, both those cars developed issues with the calipers sticking. These were new and used calipers, all dissassembled and lubed. In all cases they needed to be unfrozen, dissassembled and re-lubed. We've also had issues with these calipers on 79-81 280zx's themselves, same issue. Often this problem leads to severe rotor wear on 1 side of the rotor only, and rotor cupping. Maybe it is the environment around here that is to blame? With the later 280zx calipers we've had zero maintenance issues, spanning probably a half dozen cars and no less than a year of useage in each car, some substantially more. I was pretty convinced until I read your post that Nissan realized that the 79-81 design was flawed, so they replaced it with the 82/83 design which seems much more maintenance free. I know where my money would go anyway.

All my (limited) experience with industrial heat exchangers has found that higher flow = higher cooling efficiency. I wouldn't be surprised if there was potential to be some unique characteristics with any HTX system that may make for an optimal flow rate however. I'm interested to hear your results with the experiment for sure.

Wasn't that the post where everyone told you to buy the Azenis Sport for autocross/street duty? Glad you responded with your results though... Tire wear is a reality of racing, don't fret over it.

Any chance that you are using a 2+2 windshield in your 2 seater? The 2+2 is slightly smaller in all dimentions... hard to tell without having them side to side though.

The 82-83 rear calipers aren't that bad actually... it's the 79-81 ones that really suck. The later ones are a very similar design to the 240sx rears. Sounds like electrical to me. How are your battery cables/connections/grounds/etc?

I don't buy that for a second! If you want peak HP lots and lots of people opt for twins. I think the big draw of twins (and sequential setups) is the chance to achieve a large power bump while still retaining a fairly linear power curve. 400hp in a 2800lbs car driven by someone that can REALLY drive is pretty darn scary if you ask me. (granted scarier if the person cannot drive, but for different reasons) Power to weight ratio of 7lbs:1hp. I believe an Enzo Ferrari is just about 6:1. You are talking about building a car that is in the low 4:1 range. Granted there are lots of drag cars with better numbers than that... but that is one 'scare the crap out of anyone street car' in my books.

The turbo engines run more initial timing to try to offset the results of a lower compression ratio, and gain back some of the low rpm grunt. A NA engine has a curve that might start at 8-12*, ramp up to as much as 38* at ~3000rpm, and then carry on at that level until redline. A turbo engine will have a similar curve, starting at 20* if it has significantly lower compression ratio, ramp up to as much as 38* total at ~3000rpm and stay there until redline. The issue with the turbo is that IF you are in boost, you will want to retard the timing WHILE UNDER BOOST ONLY. That's why a lot of people use the MSD BTM box, or similar. It allows them to retard timing dependant on manifold pressure. (ie: take out 1-3* timing for every PSI of manifold [boost] pressure) In that case if you are running 10psi of boost, you might be retarding 15* of timing, which would put you at ~23* of timing, but only while under boost at 10psi. Hope that helps.

If you are looking for more power then by all means a 57 or 60 trim will be better. I like the complete package approach though. I like a car that is really drivable in all conditions. Fast spool, etc. Search the turbo forum a bit, there has been lots of discussion on the T3/T04E 50trim there, a couple of guys that have been through a lot of turbos highly recommended that setup as a great all around unit. If you are looking to drag race, you might want a turbo that makes more power in a narrower RPM range. Anyway, dyno results would be super, but only if they show the entire curves and are done on the same dyno/same car/same day/etc. Too much varience otherwise. Yo2001, I am not disputing your results with the 60-1/stage III at all.