260Z

[zracre]

I had the car for sale and can't seem to give it away...so I am putting a fuel cell in it, doing the updates and going racing with it! Any reccomendations on fuel cell size? mostly sprint races and maybe a few short HSR enduros...also how do you run the fuel pump...I have an electric one attached at the front of the stock gas tank mounting area now...just leave it? Thank you for your help in advance!!

[x-ring]

If you were a little closer I probably would have bought it, but with diesel fuel still at $2.50/gallon it would have cost as much to come get it as you wanted for it.

Anyway, I installed a 10 gallon cell, I probably should have gone with an eight (I never run enduros) and saved a few pounds. The car came with a 20 (!), which I can make you a hell of a deal on if you're interested :blink:

I mounted a Facet pump next to the differential (where the stock EFI pump is on a 280Z) and removed the mechanical pump from the engine, pretty much what you have now.

You have a PM.

[Joe Harlan]

Evan, I put pretty much 10's in them. Eights are just not big enough for much more than a sprint race. For enduros you can get by on a 12 and going in 2 hour shifts.

[JeffYoung]

Rumor is the weight on the car next year might go to 2480. Car could be competitive at that weight.

Joe, question for you. We have SEVERE understeer issues with ours. Front springs 400 I believe, 325 in the back, front bar but no rear bar (I think, need to look, been awhile since I looked after the wreck). Diff WAS a Nismo clutchpack but it was so tight it acted "locked" until it got hot -- I wonder if that was some of the understeer issue? Have acquired a Quaife that I think will help some.

Your thoughts on setup? Too much front spring?

Second question -- hot start. We are running the flattops and the car WILL NOT start if the water temp is more than 160 degrees (although it will push start).

Thoughts?

[zracre]

I forgot what my spring rates are, but I do know my car pushed like a pig without the rear bar in place...It has Tokico Illuminas and ground control coilovers/camber plates...I also ran my car with a locked diff...big mistake...the quaiffe should help but adding the rear bar will make it turn in better...my car has an open diff now and the last time I drove it at an HSR race, I could put it anywhere I wanted and it was very well balanced...just had tire spin issues on the exit of 2 corners...

[JeffYoung]

Interesting. The P.O. told us not to run the rear bar.....

[x-ring]

The PO said no rear bar? Maybe that worked for him, but it sure as hell wouldn't for me. I have to go up to a 3/4" rear and down to a 20mm front bar when I run the welded diff.

YMMV, but it doesn't sound like it.

Interesting about the weight, but it doesn't affect me. I'm usually about 50-60 lbs over without ballast. :blink:

[Joe Harlan]

Originally posted by x-ring@Dec 16 2005, 06:08 PM
The PO said no rear bar? Maybe that worked for him, but it sure as hell wouldn't for me. I have to go up to a 3/4" rear and down to a 20mm front bar when I run the welded diff.

YMMV, but it doesn't sound like it.

Interesting about the weight, but it doesn't affect me. I'm usually about 50-60 lbs over without ballast. :blink:

68533



I tend to like the cars softer than some of the eastcoasters. Normal setup out here will be some where in the 275 to 325 front with a 325 to 375 rear. 7/8 front bar with a 9/16 to 5/8 rear bar. I use Koni shocks because they work and are affordable. I still like to use a super soft tender spring to keep the shock working under all loads. If the diff if a Nismo 4 pinion and it is that tight then it is to tight. I am not a big fan of the quaife but I am also not a big fan of any torque biasing diff. That has more to do with how I drive than anything. I am also not against welding a Z diff just understand your gonna have entry push. My feeling Jeff is you have too much spring in the front and maybe the diff clutches a bit too tight. But that would be a guess without breaking the corner donw to at least 3 sections.

Entry
mid
exit

What does it do at these points and what are you doing. Sometimes a push can be overdriving the first part and never getting it back to traction.

[JeffYoung]

[quote]
Thanks guys. Ty, are you in a 260? What spring rates?

Joe, here is how it "feels" to me:

1. During the first 3-4 laps of a session/race, entry understeer was severe, mid corner understeer moderate, and a bit loose on exit. Note that when the NISMO diff is "cold" the car is impossible to push by hand with the wheel turned, just like a locked diff, leading me to believe the diff is indeed too tight.

I would try different corner entry speeds and am convinced that it was not too much speed on entry. Additionally, during mid corner throttle on, the car would push, but I could get the nose to tuck and turn with a lift, which of course killed exit speed.

What confuses this some is I am used to the TR8, which has an 85" wheelbase, turns (or spins) on a dime (which can be good or bad), and oversteers naturally because of the torque from mid-corner on. Maybe I'm expecting the Z to behave the same and overeacting when it doesn't, but the "nose slide" the car has just doesn't feel right.

2. Things get better over the course of a session as the diff heats up. But it will push the nose more than I like even when the tires and rear end are up to operating temperature.

I'll drop the springs down some I guess and see what happens.

3. Is your issue with the Quaife the fact that if you lift a wheel you lose the torque bias? I have a Quaife in the TR8, and you have to watch the curbs in the slow corners, but other than that, it seems to work pretty well.

[Joe Harlan]

Originally posted by JeffYoung+Dec 17 2005, 01:41 PM-->
<!--QuoteBegin-Joe Harlan@Dec 17 2005, 01:41 AM

Thanks guys. Ty, are you in a 260? What spring rates?

Joe, here is how it "feels" to me:

1. During the first 3-4 laps of a session/race, entry understeer was severe, mid corner understeer moderate, and a bit loose on exit. Note that when the NISMO diff is "cold" the car is impossible to push by hand with the wheel turned, just like a locked diff, leading me to believe the diff is indeed too tight.

I would try different corner entry speeds and am convinced that it was not too much speed on entry. Additionally, during mid corner throttle on, the car would push, but I could get the nose to tuck and turn with a lift, which of course killed exit speed.

What confuses this some is I am used to the TR8, which has an 85" wheelbase, turns (or spins) on a dime (which can be good or bad), and oversteers naturally because of the torque from mid-corner on. Maybe I&#39;m expecting the Z to behave the same and overeacting when it doesn&#39;t, but the "nose slide" the car has just doesn&#39;t feel right.

2. Things get better over the course of a session as the diff heats up. But it will push the nose more than I like even when the tires and rear end are up to operating temperature.

I&#39;ll drop the springs down some I guess and see what happens.

3. Is your issue with the Quaife the fact that if you lift a wheel you lose the torque bias? I have a Quaife in the TR8, and you have to watch the curbs in the slow corners, but other than that, it seems to work pretty well.

68600
[/b]

We did not establish your front bar size. ANything over 1 " is to big for IT. I also don&#39;t know what tires you are running. On goodyears I like -4.0 degrees of front camber and -3.75 in the rear I like 3/16 toe in in the rear and 1/8 out in the front. I use a welded bumpsteer spacer on the 240&#39;s I just am not sure how think for a 260. I like a rear bar on the 240 but it needs to be small. The rear spring needs to big about 50 lbs bigger in the rear to control squat that will happen of you feed throttle to quick taking weight of the front end. It sounds to me like you starting problem is too much front spring and amybe the diff is a bit too tight. I would correct the spring and get the car to turn in decent on entry and stick better in the middle. Once you have a setup that will gentally drift the rear on exit you can get a little more agressive on the diff. If you get the diff to loose you will end up with trailing throttle oversteer and or very loose on entry.

[dspillrat]

Originally posted by JeffYoung@Dec 16 2005, 09:30 PM

Joe, question for you. We have SEVERE understeer issues with ours. Front springs 400 I believe, 325 in the back, front bar but no rear bar Have acquired a Quaife that I think will help some.

Your thoughts on setup? Too much front spring?

Thoughts?

68511


HI Jeff,
When I swapped my welded diff for the quaife, My car went oversteer happy.."techie term" :P
. Had to remove the rear bar. zero toe or even a little in.
Lotsof opinions and logical reasoning regarding spring rates...I&#39;m at 400F/350R...no rear bar, 1" front bar.

YMMV Give it a whirl with the quaife. Should loosen up quite a bit. Hopefully
Good Luck,
david

[kthomas]

400/325 a little too much front bias. Rather than add rear bar, or up the rear rate, you should probably start reducing front spring as your shocks probably aren&#39;t up to the rates you&#39;re already running ( say that without knowing what you have for shocks. but I&#39;d bet they aren&#39;t up to the job).

Spring rates required for proper balance are very sensitive to roll center (which is a function of ride height and "bump steer spacer" if you have one as part of your strut) and what kind of tracks you&#39;re on. In the southeast you should be okay with more spring in front. A little toe out up front (1/16 to 3/32 total) can help a lot on turn in for the slower turns.

I don&#39;t like the way big bars wanker the chassis and on the smooth tracks we have in your region we can get roll control with spring, not bar. If you have more than 105ft-lbs preload on that diff you have too much, and 85 should work just fine. In fact, if you&#39;re on the throttle aggressively like you should be even the stock preload works fine.

[JeffYoung]

Thanks guys.

[x-ring]

Originally posted by JeffYoung@Dec 17 2005, 01:41 PM

Thanks guys. Ty, are you in a 260? What spring rates?


68600


A 260, yes. Big mistake, used to run a 280, when it came time to replace the tub (long story) the 260 was the best one I had by far. I should have found a 240 tub; when I wad this one up that&#39;s what I&#39;ll do.

Currently have 275 F and 225 R, I change the bars along with the diff as one is welded and one is the clutch type.

I need better shocks (Illuminas currently), before I up the spring rate. Two and a half months until the season opener and I&#39;m still not sure what I&#39;m going to do here; Katman says Bilstein and I now see that Joe says Koni. I had someone offer me a set of Koni&#39;s for free (they need rebuilding) but I was hesitant based on Katman&#39;s advice.

Joe, if I do go with the Koni&#39;s where should I send them for rebuild and what should I get for valving assuming I go with your advice on &#39;west coast&#39; springs (275F, 325R?).

[Joe Harlan]

Originally posted by x-ring@Dec 19 2005, 08:20 AM
A 260, yes. Big mistake, used to run a 280, when it came time to replace the tub (long story) the 260 was the best one I had by far. I should have found a 240 tub; when I wad this one up that&#39;s what I&#39;ll do.

Currently have 275 F and 225 R, I change the bars along with the diff as one is welded and one is the clutch type.

I need better shocks (Illuminas currently), before I up the spring rate. Two and a half months until the season opener and I&#39;m still not sure what I&#39;m going to do here; Katman says Bilstein and I now see that Joe says Koni. I had someone offer me a set of Koni&#39;s for free (they need rebuilding) but I was hesitant based on Katman&#39;s advice.

Joe, if I do go with the Koni&#39;s where should I send them for rebuild and what should I get for valving assuming I go with your advice on &#39;west coast&#39; springs (275F, 325R?).

68681


Send them into Koni direct. Once you have picked your spring rates so you can advise them what you are running. Bilstiens are fine shocks also I just have been a Koni guy for as long as I can think of.

[JeffYoung]

Ty, question -- assuming the 260 gets a weight break and moves down to 2480. Where the hell does the weight come off? I spent the weekend sort of looking over the car. Other than the Accusump, which I would like to keep, don&#39;t see much to take off. NO petty bar, alum. rad, Panasports, early 260 bumpers...am I missing something?

[x-ring]

>Where the hell does the weight come off?

I dunno. Like I said, I usually come in 50-60 lbs over weight without any lead. I&#39;m not exactly small, around 235 lbs, so a 180 lb guy would probably roll across right at 2610 in my car.

I do have the late bumpers, not sure how much the weight difference is, but I finally scored an early set. Just need to get them bolted up (do they use the same mounts?) before the season starts. I wonder what the weight difference is, if any, between the early and late chassis? Mine is a very late, like 10/74, build date.

What size fuel cell (fuel tank?) do you have? Mine is 12 gallons, I think. I should have bought an eight. What about the coating under the carpet? The stuff off my car it almost filled a five gallon bucket. LN2 works really well as a removal aid if you have access to it at work or whatever.

My accusump is a one quart size, all I feel I need with the baffled oil pan. I only use the cool suit when the heat is unbearable.

Get a group 34 battery (factory original size) instead of the group 24 most people have.

I guess there are a few pounds to be had with the new right side door bar rule.

Acid dip the tub? :119:

What&#39;s the build date on yours, and what weight do you roll in at?

[Ron Earp]

Originally posted by x-ring@Dec 27 2005, 11:57 AM
>Where the hell does the weight come off?

I dunno. Like I said, I usually come in 50-60 lbs over weight without any lead. I&#39;m not exactly small, around 235 lbs, so a 180 lb guy would probably roll across right at 2610 in my car.

I do have the late bumpers, not sure how much the weight difference is, but I finally scored an early set. Just need to get them bolted up (do they use the same mounts?) before the season starts. I wonder what the weight difference is, if any, between the early and late chassis? Mine is a very late, like 10/74, build date.

What size fuel cell (fuel tank?) do you have? Mine is 12 gallons, I think. I should have bought an eight. What about the coating under the carpet? The stuff off my car it almost filled a five gallon bucket. LN2 works really well as a removal aid if you have access to it at work or whatever.

My accusump is a one quart size, all I feel I need with the baffled oil pan. I only use the cool suit when the heat is unbearable.

Get a group 34 battery (factory original size) instead of the group 24 most people have.

I guess there are a few pounds to be had with the new right side door bar rule.

Acid dip the tub? :119:

What&#39;s the build date on yours, and what weight do you roll in at?

69282



Not sure where the weight is gonna come from either. Our car build date is sometihng like August of 74 and, according to the log book, some previous owners had tried to pass the car off as a 240z. Must have been found out in the past since when we got it she was all 260s, flat top carbs and all.

We have early bumpers. Battery is too big, I can tell that, or at least, the old battery was too big and I don&#39;t know what we have since Jeff replaced that. Fuel cell is huge and steel, with too many supports holding it in place. I think I put 15 gallons in it one time, so I&#39;d guess whatever FuelSafe cell is close to that. Probably needs a 8 or 10.

Car is stripped solid to the chassis, it has been a race car since 1991 I think. It does have a good cage, but, I like a good cage so we&#39;re not pulling weight there. Nice NASCAR bars, good trianglation.

We do have the good baffled road race pan, I think the big Accusump can hit the road, as well as the expensive Olberg filter. That will drop some weight. We&#39;ve also got redundant fire systems, but, after catching on fire from my stupidity :bash_1_: in my first race ever last year at CMP I&#39;m sort of thinking the fire systems are fine.

Exhaust system is short and side exit, but with muffler. The muffler can go, losing about 10lbs there.

R

[JeffYoung]

Thanks Ron. I think that about covers it except:

1. Ty, with Ron (165 lbs) and me (185) driving we come in right at weight. Might even should run 25 lbs ballast to be safe, but still, not sure we can find another 100 lbs.

2. Car is a bare tub. As close to acid-dipped as I think you can get.

3. Ours had the lightweight, very thin chrome bumpers but it also had these heavy oil-filled shock mounts. No idea if the later bumpers will mount up to them.

We&#39;ve probably got some weight in the cell to lose, but that is expensive in that it requires a new cell. So, 2610 it is I guess, for now anyway.

[x-ring]

Hmm, I wonder if 8/74 originally had the big bumpers? The oil filled shock bumper mounts were used for both late and early build, but have different part numbers. The mounting holes to the frame look to be the same; I wonder if they&#39;ll interchange?

I would think twice about the accusump. Even with the baffled pan I would get an oil pressure light flicker in a hard right hander. I think my light comes on at 20 lb/in^2. The one quart &#39;sump seems to have taken care of it and is quite a bit lighter than the three quart version most people run.

[JeffYoung]

Yes, we will keep the Accusump. Cheap insurance in my view. I DON&#39;T want to lift that heavy-azz iron straight six out of that car anytime soon.