300ZX In ITR

[lateapex911]

OMG they are starting to merge into one being !

Keep up the good work.
[/b]

I laughed when I read your post and thought, "Where'd he dig up that old quote from Andy??"...then I saw the post time! Duh...EXACTLY the same!

I guess you can say that at least two ITAC guys share the same view, LOL.

(But in actuality, the commitee as a whole does too.)

[DavidM]

David, when you tracked your car, was the issue:

1. It just didn't stop like a lighter car OR

2. The brake system could not dissipate the heat adequately resulting boiled fluid, melted caliper seals, etc.?

No. 1 is something you can deal with on track. Just a racing disadvantage for the car. No. 2 is a fundamental design flaw that PREVENTS you from racing/finishing races (ask me how I know).

If it is 2, I agree, the car should be avoided. If it is 1, I can live with that.
[/b]

It takes a long time to stop compared to a lighter car, but seems like it should be able to stop quicker. The Z is pretty much my fun/weekend car and I still have to adjust my braking distance whenever I drive it. I have stock brakes with semi-metallic pads and stainless brake lines so it's not a full race setup. I've never really liked the pedal feel, but that may just be me.

I was pretty much a track newb when I had it on the track though I had autocrossed for a couple years. I definitely wasn't hammering the brakes and I never felt any fade (though I did start to overheat, but that's another issue). I have talked to other people that have experienced significant fade on the track. This was a long time ago and I don't recall the exact situation or track. The stock front undertray has some brake channeling ducts built into it, but some good ducting may alleviate the fading issues. I think it'd still take you a long time to slow down compared to other cars. Better have a big lead before you get to the brake zone.

I'm kind of wondering if the car is going to be able to get down to weight. Was it 3250? and that's with driver. So you figure the car needs to be 3050-3100 without driver. The car is somewhere between 3400 and 3500 stock (slicktop is about 100 lbs less). That's 400 lbs to lose. You'll get 60-70lbs in seats and maybe 50-75 lbs in plastic trim, sound deadening, and carpet. I don't know where you're going to find another 250+ lbs. What do you do with T-tops? Those are pretty heavy. The spare tire is a miniature, but that's some weight. I think it'll be tough.

I hope somebody proves us wrong as this is one of my favorite cars (which is why I own one).

David

[Ron Earp]

I'm kind of wondering if the car is going to be able to get down to weight. Was it 3250? and that's with driver. So you figure the car needs to be 3050-3100 without driver. The car is somewhere between 3400 and 3500 stock (slicktop is about 100 lbs less). That's 400 lbs to lose. You'll get 60-70lbs in seats and maybe 50-75 lbs in plastic trim, sound deadening, and carpet. I don't know where you're going to find another 250+ lbs. What do you do with T-tops? Those are pretty heavy. The spare tire is a miniature, but that's some weight. I think it'll be tough.
[/b]

It won't be as tough as you think I bet:

Electric windows
Electric mirrors
Full power seats - probably heavier than you estimate
Full interior
Door panels
All carpet and sound deadening
All AC - compressor, evap, condensor, drier, hoses
HVAC controls
Radio - lots of speakers, and wire
T-tops - replace with 0.040" steel panel welded in place
Radiator with ally unit
Full exhaust replaced with a much lighter unit
Cat removed
Cruise control
EGR systems and plumbing
Spare chucked
Jack chucked
Light weight wheels used

And I bet a lot more.

That car is going to be a fast car when fully developed and I bet it'll be competitive. Maybe we'll have to do the swept area per ton on brakes again to show that it is probably not much worse off than other ITR cars, and might be better than a few. I wouldn't let everyone get you down on it, you can bet they will be built and once some top builds come out to play they'll be contenders.

Ron

[Joe Harlan]

When I proposed this car for ITS with a restrictor I proposed 3250 figuring ITS times and speeds. The factory curb weight is 3299 so I suspect making weight will not be an issue. I worked on one of these for a drift kid with nothing in it but a cage and 19inch wheels it was 2948 on my scales.

I think it will be an OK car but it will not be a top level deal amoung the other cars listed at a full prep and drive level. I am also saying this as a guy that has actually driven many of these and several time on track days. Good luck use Hawk pads HB178s fronts and HB 179S rears. I stock them and line kits also if you can't find them easy.


Joe

[Ron Earp]

When I proposed this car for ITS with a restrictor I proposed 3250 figuring ITS times and speeds.

I think it will be an OK car but it will not be a top level deal amoung the other cars listed at a full prep and drive level.
[/b]

In ITR the same Z is classed at 3250 lbs.

Basically you are saying that a couple seconds per lap faster, at the same weight, will turn this car from a good one (Z in ITS with restrictor) to a medicore or bad one (Z in ITR without restrictor)?

Regardless, it is pretty clear the use of restrictors in IT didn't work too well and folks overwhelmingly wished to have a new class without restrictors. Forcing all newly classed cars into S with restrictors seemed like a bad idea.

Ron

[Joe Harlan]

Well again I see why I quit posting here. WIth your vast experience with these cars Ron I am sure you are right. Anyone that decided to actually build one is welcome to contact me offline. Expressing a view here based on actual experience is like pissing in the wind and I just don't have time for it.

The issue Ron is that a restricted engine in ITS would have kept the speeds and costs of running these car real.

Decent chassis: 4500
Pro Engine 9000
Fresh trans 1000
Brakes 1000
Diff 1400
cage 2500
Cell 1000
Safety 1000
Shocks 5000 for a mid rage set
Wheels 2500

So with some misc stuff added 30K before paint and graphics. You aren't going to see 50 cars built in a 2 year period unless the car is proven to be extremely competive out of the box. These cars never had 240z following when they were new and Nissan couldn't sell this great little sports car in any serious numbers for 26k new.

As they say Enjoy the ride.

[Ron Earp]

Is the issue here performance of the Z or how IT should be? Fact is, folks don't care for restrictor plates in IT. It is one of the many reasons ITR exists, and only one of many reasons I think ITR will be a popular class.

I'm sure you've forgotten more about Zs than I'll ever know. But I don't see a restricted Z being any cheaper than a unrestricted Z to build really. All those costs you listed are pretty much fixed, plate or no plate. Are there 50 of anything in IT anywhere, besides Miatas, RX7s, and old Z cars? How much faster do you think an unrestricted Z is going to be?

[DavidM]

The factory curb weight is 3299 so I suspect making weight will not be an issue. I worked on one of these for a drift kid with nothing in it but a cage and 19inch wheels it was 2948 on my scales.
[/b]

I've seen the 3299 number, but most Z people seem to consider it a myth. I've never had mine on a scale so that might be interesting. I've got a body kit and 18" wheels so I'd have to subtract some weight for those. 2948 is impressive and definitely shows the car can make weight anyways. That was a T-top car? Weight was without the T-tops?

David

[Joe Harlan]

Ron, The kitchen table rule applies with a restrictor and since we both know you have even less experience wit restrictors than I do, I will respond one last time. The kitchen table rule is engines and gears boxes can be built by the average party on the kitchen table rather than needing a Professional like myself. SO we cut the price of a 9k engine down to 3500 bucks and the cost of a trans in half. The Idea is if the restrictor will hold the power well below the expected max effort then the Max effort is not needed for a reasonble program to exist. Most people stay on the fench because they don't believe they have the skills to put together a Max effort anything. IT used to be the best place for those kind of people until all of us Pros started building parts and raising the bar. SM is a perfect example of Pros gone wild. If you properly use restrictors you could balance the class and drive most of the pros out of the game.

The car that was used for that project had a sunroof if I remember correctly.

[JoshS]

The Idea is if the restrictor will hold the power well below the expected max effort then the Max effort is not needed for a reasonble program to exist. [/b]

Joe, this confuses me. Are you saying that a pro-built motor won't make any more power than a kitchen table motor if they have the same restrictor?

That doesn't make sense. We can consider the stock intake as a restrictor (just not as restrictive as something that we might add later.) And with that stock restrictor, pro-built engines are better than kitchen-table engines, right? Why would the addition of a restrictor change that?

[Joe Harlan]

Lets say the target for the car in IT trim is 225 Hp...This would be a number that anyone could get to pro or Kitchen table... But If I the pro rub on it really hard I may get 230...Now everyone needs 230 just to keep up.. If you add a engineered restrictor to 225 it really does not matter if I find 245 unrestricted if with said restictor we are all stuck at or very near the original 225 target. The issue some have in this club is that unless you spend the crap out of your kids college fund you have not fully developed a "race car" Unfortunately that is why we are loosing this sport.

[zchris]

Joe is correct. In IT where you have a compression and cam spec, the SIR is a great equalizer tool. I wish in GT we had a maximum spec for compression. We now have to build 15 to 1 motors in limited prep to maximze the SIR. Exactly what is was supposed to eliminate. Turning the term Limited Prep into somewhat of a myth. Joes also correct about the lack of brakes on the 300zx. Seen several hit the turn 3 wall at NHIS because the brakes went away. Not even the Nissan Comp big brake kit solved the problem. Just to damn heavy. Chris Howard

[JoshS]

Sorry Joe, I'm still a little lost. How do you have a restrictor engineered to 225hp? That same restrictor in a pro-built motor might still get 235 when a kitchen-table motor with that same restrictor would get 225, no?

Are you saying that if there's a restrictor, that no amount of pro engineering can turn out more hp?

[Ron Earp]

Are you saying that if there's a restrictor, that no amount of pro engineering can turn out more hp?
[/b]

Certainly there will be some gains.

I think the opposite of what some predict will happen - put a restrictor on it and people will spend insane amounts of money to get those last 2 ft lbs, or maximize that area under the curve with the restrictor. About what we do now. Certainly more work and development with the restrictor will net some gains, they'll just be smaller and cost a lot of time/money and or both.

Fortunately, it is moot. I think we've all seen how well the restrictors worked with the BMWs and I doubt many want a repeat of that experiment.

Ron

[Joe Harlan]

Sorry Joe, I'm still a little lost. How do you have a restrictor engineered to 225hp? That same restrictor in a pro-built motor might still get 235 when a kitchen-table motor with that same restrictor would get 225, no?

Are you saying that if there's a restrictor, that no amount of pro engineering can turn out more hp?
[/b]

Josh, Lets put it this way. If said restrictor can only move X amount of air and compression and cams are a fixed number then gains will be minimal at best and lets say we are talking 3 to 4 HP difference. I can tell you for a fact that the difference between a tabletop and a pro motor is way different than that now. YOu have a turbo car so you understand the effects of air. If you had a restrictor on the intake side of your turbo with say a 27mm hole you could only ever make as much boost as 27mm would flow. At a certain point 27mm stalls and can not allow any further air volume to flow.

Ron you only think it's a dead deal...Look at the number of classes using them and starting to use them there is no doubt in my mind that they will be in use everywhere in the next 5 years. I personally think they would be awsome in Spec Miata....That would get rid of all the advantages of a pro motor.

Thanks Chris and I competely agree that a max compression should be looked at for GT to limit how far people will go to try to cheat the effects of the SIR, Or have the sir engineered and sized based on compression number.

[Stan]

Josh, Lets put it this way. If said restrictor can only move X amount of air and compression and cams are a fixed number then gains will be minimal at best and lets say we are talking 3 to 4 HP difference. I can tell you for a fact that the difference between a tabletop and a pro motor is way different than that now.[/b]

True. We are seeing 15+ hp difference in the 1.6L Miata between crate and carefully prepared legal pro motors. A 3.0L 300ZX motor will show linear improvement from that.

At a certain point 27mm stalls and can not allow any further air volume to flow.[/b]

True again, but air flow alone is not the whole story. An engine will make power with a given SIR in linear relation to its specific output. That's a fancy way of saying that Josh is correct in post #33, and a pro built engine will enjoy a power advantage over the kitchen table engine, assuming they use the same size SIR. Raetech and Loyning Engine Service have shown the Club over and over again that the SIR must be matched to the engine preparation level to assure the desired output. One size does NOT fit all.

Ron you only think it's a dead deal...Look at the number of classes using them and starting to use them there is no doubt in my mind that they will be in use everywhere in the next 5 years. I personally think they would be awsome in Spec Miata....That would get rid of all the advantages of a pro motor.[/b]

It is true that we will see intake restrictors more comprehensively employed in future. Not all will be SIRs, but restrictors are the coming thing. See my comments above about the advantages of pro motors...

Thanks Chris and I competely agree that a max compression should be looked at for GT to limit how far people will go to try to cheat the effects of the SIR, Or have the sir engineered and sized based on compression number.[/b]

Both approaches are under discussion.

Stan

[Ron Earp]

Ron you only think it's a dead deal...Look at the number of classes using them and starting to use them there is no doubt in my mind that they will be in use everywhere in the next 5 years. I personally think they would be awsome in Spec Miata....That would get rid of all the advantages of a pro motor.
[/b]

I hope it is a dead deal. You and I will be around in five years, we can see where it stands then.

Fortunately at least in this latest round of IT development, they did not "win". If they had, we would've seen all these nice cars we just classed in ITR dumbed down in performance and stuffed into S.

Where is the fun in that for the racer? Why would a racer wish to build a late-model restricted Supra so he could run in ITS with S cars? Why not build the cheaper S car then? And there we are, with IT stuck in the past with no new cars. IT needs new cars, and new faces driving them, and getting new cars into the class can make that happen.

Restrictors might be great for a spec class where everybody runs the same engine and chassis. But IT isn't like that, IT is full of differences. And differences is what makes IT interesting for a great many folks.

Ron

[Joe Harlan]

True. We are seeing 15+ hp difference in the 1.6L Miata between crate and carefully prepared legal pro motors. A 3.0L 300ZX motor will show linear improvement from that.
True again, but air flow alone is not the whole story. An engine will make power with a given SIR in linear relation to its specific output. That's a fancy way of saying that Josh is correct in post #33, and a pro built engine will enjoy a power advantage over the kitchen table engine, assuming they use the same size SIR. Raetech and Loyning Engine Service have shown the Club over and over again that the SIR must be matched to the engine preparation level to assure the desired output. One size does NOT fit all.
It is true that we will see intake restrictors more comprehensively employed in future. Not all will be SIRs, but restrictors are the coming thing. See my comments above about the advantages of pro motors...
Both approaches are under discussion.

Stan
[/b]

Stan, I agree in GT type prep the gains between pro and kitchen are still to far apart but I believe we have far less issues in IT to deal with.

Ron as a club we need to find ways of having more car and less classes so we can look at a future of allowing your wombat 3000 nto be fit into a regional or national (or both) program at different levels of prep. My vision would a set of classes that would have a plce for my 350z to run the ARRC and the runoffs in the same year... We need to get back to competition instead of trophy collecting. I will look at every tool in the box with an open mind but more classes needs to be the least used tool. If folks want to solo1 then thats what they should build cars for.

[JeffYoung]

Joe, have to disagree )imagine that). ITR is not a new class, it is a new classification within an existing ruleset (IT) to account for newer, faster cars. Itś not an entirely new category, a la GT, Prod, T, etc.

Lots of folks dont want to hear this, and I know there is no intent to do away with ITC and ITB, but the fact remains that there siply arent many, if any, new cars that can be classed in C and B given the performance potential of cars today. ITR is simply a recognition of this fact, and a shifting of existing the existing IT classification "up" performance wise to account for that.

Everyone I have talked to, here on line, in teh paddock, etc. thinks this is a good, if not great, idea. Still struggling with why you dont (and not tying to be rude).

[Joe Harlan]

Jeff, No where have you seen me say that ITR is not a good idea. I just feel that you all missed the boat and cut the pie to thin. There is clearly a need but the BOD needs to have a full club wide plan of attack rather than just a little piece of the pie. I offered a true based on experience thought On what I thought of this car and lets see Post number how many I had to take shit for offering facts....Facts! not "well it looks good on paper". I have driven these cars in about every config you can think of and it is a bitchen car but it won't hunt a M3 and now that the pie is cut so close where you gonna put the 350z at 300 flywheel HP in 2 years?....