Drax240z

I'm finding at 9psi boost/stock turbo on my L28ET/240z that I have almost too much power for autocross too... it's all about traction, not power!

My big problem with those mags pete is that their tech is REALLY basic for the most part. They are lagging 20 years behind SCC for their tech articles content IMHO. Just buy Grassroots Motorsports and Racecar Engineering and be done with it.

How the 350z can rate higher than the 240z is sooooo far beyond me.

It depends on the method of linking the ends to the bar. If it is free floating (rod ends) then they stress should be uniform compression or tension. If the bar is rigidly mounted on the ends, then there will be some bending loads induced and the stresses at the end of the bar could be higher than the rest of the bar.

Holy crap, that thing is pig rich too!

Proper break in is key with any friction surface like a clutch, tires, brake pads, etc. As some of you have found out the hard way! Clutch: 500miles of CITY driving (ie: stop and go) before applying full engine power. Tires: Most like an initial heat cycle, followed by 24 hours cooling time while not on the car. (R-compounds anyway) Brake pads: 6 or 7 'slows' from 50mph to ~5mph, without bringing the vehicle completely to a stop. Brakes should then cool for 1 hour without being driven.

Skip the Major head work and spend the money on a more efficient turbo such as a GT series ball bearing unit. Or spend that money on stand alone EFI.... or a better IC. I'd stay away from water injection personally, a quality intercooler is all you need. I am not crazy about having to fill up anything but the gas tank. My recepie for 350 rear wheel: L28ET Forged pistons, 8.0-8.5:1 CR SDS EFI (EM-4F) Medium NPR Intercooler 400cc/min injectors or a bit larger Walbro GSL392 Fuel pump 3" mandrel bent exhaust Large mandrel bent downpipe 240sx 60mm TB GT30R Turbo You better have some pretty serious plans for brakes, suspension and traction as well with this setup!

225mm CFDF's run $300-$325 these days. 240mm CFDF's are ~$400 canadian.

Search search search. There is lots of info on SDS here. When it comes time to order one, shoot me an email. I can save you a few bucks in the end... just trying to get my volume up!

Scott, can you seal up the BOV with something to effectively eliminate it from the system and see if your problems go away?

Hey Clint, that isn't a bad idea. I might give that a try in the next little while.

It's a by product of the L28ET engine I believe. My car also exhibits similar traits. With the wideband on mine I leaned out the idle significantly from ~11.5:1 (where it ran smooth) to ~13:1 (where it is a bit rougher). I've come to the conclusion that these engines simply need to run rich at idle to be smooth. With that in mind, you can gain a lot in the way of throttle response by leaning it out under light/mid throttle.

Wheel alignments are a good thing. (I just had one done today!) Actually the impressive part was that I managed to dial in my rear suspension to within 0.2* camber, and 0.05* toe with just eyeball and a tape measure. We put it on the rack and that blew me away. So with that in mind you can get pretty close with eyeball and a tape, check your alignment that way, you'll know if it's way off.

Those are some sexy shoes... I wish I had a set of Volk's!

My advice: Try to take pictures without shaking the camera at the same time. Are you too excited or something?

Unfortunately you can't say that with such certainty without knowing the yield limit of the steel part being tested. If 37,500psi is below the yield limit of the part being tested then the test could go on forever, barring any stress risers. If that's true, then the bar being stressed at 37,500psi will last just as long as the bar being stressed at 5,500psi. Yeah I covered that in the rest of that post. I should reword it a bit to be more clear. Fatigue life will be shorter as stress increases, except in the case where the stress is below the endurance limit of the said material, where the material can then have an infinite life. How's that?

Another factor that can be illustrated by the stresses present in each bar is the bars fatigue life. Guess which bar will last longer, the one experiencing 5500psi or the one experiencing 37500psi? Likely using steel each bar will have an infinite fatigue life, but it is another thing to consider. The higher the stress the lower the fatigue life. (a generalization, because there is a point of effectively infinite fatigue life) But an useful rule of thumb all the same.

I think you can pretty much sum up the word "engineering" as "the search for efficiency". In this case, you certainly could make a curved bar with the same stiffness and strength as a straight bar by using much more material, it just wouldn't be as efficient. The 1050lbs figure is an estimate of the worst case scenario. We don't really care that much about this if we aren't considering the worst case.... It has been discussed over and over here that there is no advantage to a strut tower bar with rod ends on it, other than adjustability. The more constraints splaced on the tower by the bar, the better overall the chassis will feel. The idea is to resist movement, not to keep the bars parallel. A stiffer chassis is ALWAYS of benefit, even with a soft suspension. (the only exception being when your chassis IS your suspension) The stiffer the chassis is, the more predictable it is, and the easier it is to make consistant changes to the suspension. This is independant of spring rate, but would be more noticeable at higher rates most likely.

Sorry, my 3000lb load was assuming absolute worst case, one tire on the ground. John is right that it would be very difficult to pull a 1.5G corner on 1 tire. However, also as john mentions the most significant loading is shock loading from potholes etc, where suspension loads can be easily as high as those experienced in a 3G corner.

OK Jersey... you really aren't making much sense to me here. It is NOT. That is a fact!!!!!! --------- Case 1: --------- Assuming a Z of 3000lbs mass, cornering at an instantaneous 1.5g/s. Lower control arm pivot is 7" from the ground. (assuming a 24" tall tire) Height to strut tower is 30" from the ground. We have 4500lbf acting on the contact patch of the tire. We have 1050lbf acting on the top of the strut tower. Assume worst case scenario is that the chassis is stiff enough for the unloaded strut tower to be stationary. We then have 1050lbf of compression on the strut tower bar. A standard 1" OD, 0.065" wall tubing will have a x-sectional area of 0.191in^2, leading to a stress of 5500psi. Assuming run of the mill mild steel, (E=29x10^6psi) there will be a compression of .006824". --------- Case 2: --------- Same loading and assumptions as above, only this time the bar is under bending loads as well as compressive. (ie: bent bar) Simplifying the bent beam to being 3 sections of 12" in length, with a 1.5" (centerline to centerline) offset, and again using 1"OD, 0.065" tubing. All of a sudden we have stresses of 37,500psi. (bending moment 1575lb*in, 0.5" from neutral axis, moment of inertia being 2.097*10^-2 in^4) Case 1 (straight bar): Pure compression: 5500psi stress Case 2 (bent bar): Bending loads: 37,500psi stress on bar It's a royal pain in the arse to figure out the final overall deflection of the bent bar, but the stresses should give you an idea of the overall shape of the bars in these 2 situations. If the actual dimentions are even close to this I know which bar I'd be using. (oh wait, I allready am!)

Hey sounds just like my car. I thought it was normal?

Or for those of us that want 275 hp without spending $7000 on headwork.

I thought it was obvious I meant all other things being equal. Ie: Same OD, wall thickness, material etc. Given Jersey's application I am sure it is all the bar he needs. However, consider this: A close friend was sideswiped in his Z about 4 years ago, the thing that saved his life was his rear strut tower bar, otherwise the truck that had hit him (just behind the drivers door) would have done significantly more damage. Now, Jersey's bar may well be strong enough for that application, but... Certainly it is better than nothing. Certainly is is a great use for an otherwise hideous piece of Datsun. And certainly a straight bar is stiffer! (all else being equal)

First off this is a technical discussion not an arguement. In my opinion that means it is void of emotion and therefore we can't be stepping on each others toes. Ahha! The problem with this logic is that the bar doesn't stay rigid until you pass some force value, no matter what force you apply to the bar it will move! So if you apply X lbs force to your curved bar, it will deflect Y amount. If X is larger, Y is larger. A straight bar will deflect less than a curved bar under axial loading.