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My Dream LS7GTZ.......project underway


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Matt, Let me give you a little advice... Don't let this car sit forever while you're sorting all the small details. If you can get the car out on the track and start de-bugging it (enjoying it) you'll be happier. Mine has less than 200 miles in 10 years of long, drawn out build. I'd get it on the track as soon as you can so you can chase down all the other "little" things.

 

I've been working with kydex for about two years now. You'll probably get away with about 3/8th inch kydex for the splitter. I'd also think long and hard about that rear difuser. We got some really good advice from the engineers when we were at the windtunnel in 2007. There's good reason why I've not bothered with it.

 

Enjoying reading about your build. Takes away from the frustration and Thousands spent on mine!

 

Mike

 

Mike,

After being at the shop today we have decided to go ahead and take it to the track and see where we stand before doing a lot of the "little things". We can sort out the aero and such when we have a better idea of how the car is balanced, where it gets loose and so forth. I appreciate your advice and agree with you. Car is going to alignement next week. We have to build the enclosure for the fuel cell and oil tank. Do some minor body work and we are off to the track. Also for the record..... I think is was someone elses comment about leaving porsches behind. I'm sure I'll have a few that are matched more evenly but to think I will be passing any cup cars is absurd. I'm fully aware of the porsches capabilities. Thats not to say that some porsche drivers wont stop and say "That Datsun is fast as hell".

 

Matt

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There is nothing about the Z in particular that makes it incompatible with a diffuser. The cars in the wind tunnel test were all WAY too high and I'd guess too softly sprung to make good use of a diffuser, and all had relatively bad aero at the front except TitaniumZ's car and even his didn't have a rad duct so there was still a lot of air spilling underneath the car. It shouldn't be too surprising then that the expert said the diffuser would be a complete waste.

 

Just judging by the rest of the build, I would think that Matt's car would be a good candidate or it might be said that Matt is a better candidate to get it done than most, especially if he's looking at doing a flat bottom. Toughest part about paneling the bottom of a Z IMO is the exhaust, so you might look at some GT2 style cars and how they run the exhaust through the passenger floor or sidepipes to get the exhaust out of the way. Not a big fan of sidepipes in general, but if you look at some pictures of Zs running them, it's tough to argue with the ground clearance and the space cleared up underneath. I don't know that anyone has actually done a flat bottom Z, so there are issues like driveline cooling that you'd have to break new ground on as well...

Edited by JMortensen
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I might be off here, but I seem to recall reading that side skirts also help the aero of a Z. If you did the side pipes, you could possibly work those to act as side skirts as well, while freeing up space under the car at the same time. Would probably require custom pipes though, or work to the rockers and I don't know if that would affect exhaust flow.

 

Just some food for thought.

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Actually the Engineer stressed that the whole underside of the datsun Z does not lend well to a rear difuser. The lack of solid bottom panels front to rear add to the mix. He also advised us that working to get rid of dirty air in the engine compartment was futile. Both were better off left to "fill" to capacity, much like the interior filling up with air. As you mention, Jon, It's going to be hard. The engineer advised to spend attention elsewhere... closing off the front end, ducting the radiator, adding splitters and well balanced rear treatments...Matt clearly has the talent, but will it pay out in functional pieces or be a wasted effort?

 

I'll offer this much up, When My car is put in the tunnel I'll be happy to test ANY PART ANYONE can get to me before the test. We can put all the questions to bed by doing real tests and colleting real data, Again.

 

There is nothing about the Z in particular that makes it incompatible with a diffuser. The cars in the wind tunnel test were all WAY too high and I'd guess too softly sprung to make good use of a diffuser, and all had relatively bad aero at the front except TitaniumZ's car and even his didn't have a rad duct so there was still a lot of air spilling underneath the car. It shouldn't be too surprising then that the expert said the diffuser would be a complete waste.

 

Just judging by the rest of the build, I would think that Matt's car would be a good candidate or it might be said that Matt is a better candidate to get it done than most, especially if he's looking at doing a flat bottom. Toughest part about paneling the bottom of a Z IMO is the exhaust, so you might look at some GT2 style cars and how they run the exhaust through the passenger floor or sidepipes to get the exhaust out of the way. Not a big fan of sidepipes in general, but if you look at some pictures of Zs running them, it's tough to argue with the ground clearance and the space cleared up underneath. I don't know that anyone has actually done a flat bottom Z, so there are issues like driveline cooling that you'd have to break new ground on as well...

Edited by Mikelly
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The engineer advised to spend attention elsewhere... ducting the radiator...

Why so much resistance to this exact idea when I brought it up after the test then? (see posts 3-8): http://forums.hybrid...-datsun-s-30-z/

 

Matt is talking about paneling the whole underside of the car. If the whole underside of the car is paneled, then the lack of paneling as a critique against running a diffuser doesn't make a lot of sense. It's all about context. Diffuser on a stock Z at stock height that bobs up and down all over the place? No. Diffuser on a Z with flat bottom? Why not? Will it make a difference? If the whole underside is flat, it should. How much? Is it worth the effort? You'd have to actually do it and then compare lap times or test in the tunnel to find out for sure. Based on some of the time trialing cars that have been kicking ass and taking names in the past few years and the emails I've traded with Simon McBeath and posted here, I'd say it's probably worth a shot.

Edited by JMortensen
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Actually the Engineer stressed that the whole underside of the datsun Z does not lend well to a rear difuser. The lack of solid bottom panels front to rear add to the mix. He also advised us that working to get rid of dirty air in the engine compartment was futile. Both were better off left to "fill" to capacity, much like the interior filling up with air. As you mention, Jon, It's going to be hard. The engineer advised to spend attention elsewhere... closing off the front end, ducting the radiator, adding splitters and well balanced rear treatments...Matt clearly has the talent, but will it pay out in functional pieces or be a wasted effort?

 

I'll offer this much up, When My car is put in the tunnel I'll be happy to test ANY PART ANYONE can get to me before the test. We can put all the questions to bed by doing real tests and colleting real data, Again.

 

Mike,

What wind tunnel facility did you go to and where? I would also like to know what you paid if you dont mind me asking. Last time I checked it was around $4,000 per hour at a top notch facility with engineer input. I respect everyones opinion and appreciate even the fact that you take the time to comment on my thread. Our plan is to develop a splitter for the front. You mentioned 3/8 Tydex instead of 1/2 inch. I agree that 3/8 would be fine. Most every weekend racer program I know uses 3/8. I thought the 1/2 inch would obviously be more sturdy, every Sprint Cup team uses 1/2" Tydex for their splitters so I know that works too. My thought was the G nose is not flimsy but it is also not exactly sturdy. The 1/2" would help stabilize the lip of the air dam where it is the weakest. This would be one piece that works back to the lateral frame rail, that I cut out the stock one to allow more air to the bottom 2" of radiator. I replaced it with tube frame. The bottom of the car will be two pieces. One left and one right, I've attached a picture. I am going to have to leave the center open as the exhuast pipes need to breath. It will cause too much heat in the cockpit if not. After much research I have found this to be common practice with lots of flat bottom cars. There is even data that shows it to be helpful. The rear diffuser will be the challenge. I read lots and lots of data from other race teams and the equation for success is in trial and error. The slope should be around 14 degrees to start with. How far out the back it exits is a variable to consider. I know I can just take the car to the track and have fun with or without it. Our plan is to do laps and take our average without any of the aero items in place, (splitter, dive planes, wing vs three pice tail, underpanels, diffuser). Then start adding the pieces and see if it adds or takes away from performance. The car has an AIM data logger so this info will be fairly simple. Trying different combinations would be the next step. This is not about making the car look "street cool", this is about performance. A good friend of mine who is last years Grand Am champion with Brumos porsche, #59, is looking forward to driving the car and is excited to help me set it up. I trust my driving is good but he is a machine and during this process I need a constant in the equation. That's Lee Keen.

 

I will share all the pictures and results of this once we are finished testing.

 

Thanks to everyone for their helpful input.

 

Matt

post-13190-006469400 1331518241_thumb.jpg

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Jon, It's been five years since that test and I'm just bringing up the experts advice that was given to us at the test. I don't "know" enough about aerodynamics to claim to be an expert. So when someone who works in a windtunnel every day, with NASCAR Pro teams tells me (and the others who were present, about 12 members) that it would be a waste of effort and you could better spend your time elsewhere on the car, I listen. Not trying to argue with you, just relaying what an expert told me.

 

Matt, We used the Aerodyn2 Facility in Mooresville North Carolina. There are two facilities on their grounds. One has a rolling deck to simulate rolling resistance. The other, which is the one we used, has a solid wood floor with the ability to trail smoke. Using smoke is more expensive and time consuming, so we did tufts of yarn. I believe we spent about $4200 for a total of 32 runs. We were in the tunnel for 9 hours with four cars. I wrote an Article in NissanSport Magazine and they host all the footage on youtube.

 

Again, I'm not "resisting" the tests. Just relaying what was told to our group.

 

Mike

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Took the day to assemble the front nose of the car. Over a year ago we molded some carbon fiber head light covers. I still need to work on them a little and I ran out of rivets. (Bad thing is...I can't find the box I had the glass ones we made the molds from. They were expensive as hell and I've missplaced the damn box).

Got the Air Dam on and all the Z tabs in place. I was really worried about how flimsy it seemed prior to installation. After brackets and all were in it's solid. Very surprised.

I had to cut a small section of the hood out to allow clearance of the LS7 altenator. I plan on doing a very small "Gurney Bubble" to cover it. I can't even see it from inside the car so I was happy about that.

I'll take the trailer tomorrow. I have an appointment to get the alignement done (Grand Turismo).

We got a sheet metal bender at the shop to assist us with the Fuel cell and oil tank cover/surround to meet regulations. It will make the job so much easier and look seamless as well.

 

Took a few pictures. She's a sexy beast.............

 

 

Edit:

Sorry.........I forgot to downsize the picture first.

post-13190-035725200 1331775924_thumb.jpg

Edited by cobramatt
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GT? I might need to sneek a peek at your ride, if you don't mind. I work at a shop close by.

 

Would love for you to. Won't be there tomorrow as I am taking her to Grand Turismo. Then back to finish some metel work. Give me a call 4042180588. What shop are you at?

 

Matt

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Matt, Seriously thinking about going with a Gnose/IMSA setup as well... Love the flow of the bodywork on your car... If mine doesn't sell, I may well convert it over the winter!

 

Mike,

 

A wise man said to me once, "dont keep working on all the little details with my build. Get it out on the track.........."

 

That was you who said that........

 

Ever since I had my first 240 33 years ago. I was always drawn to the shape of the Z car. When I saw my first IMSA race, I was blown away with the way the g nose changed the entire look of the car. Over the years I've come to realize that if a Z doesn't have IMSA flares that flow into the G nose it doesn't look right. In my opinion. The balance of making the car wider offsets the longer front end. Without the flares the nose looks out of place. I appreciate the comment.

 

Today didn't go quite as I had planned.............. Long story made short. Everything I touched today either broke, didn't happen, or just basically took a step backwards. To the point where I'm actually laughing. A true comedy of errors.

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Glad you can laugh at those times... I've had so many of them over the last ten years, it's become that albatross around my neck! Hoping to be at the track in April and it's actually looking like it'll happen with each passing day.

 

Mike

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Spent a fantastic day at the dyno. Working on the suspension. Got a few leaks we gotta work out but nothing major. Realized the brand new altenator from GM is toast. I was wondering what this faint noise was and when I looked the pully was not going aroung near as fast as the belt. I'm no brain surgeon but that seemed at bit off. We called the dealership and they will warranty it but they need a vin# off the vette it went in. I guess well just find a good random vette vin# on e bay tomorrow and run it up the flagpole and see if it flys. Hope you like the video, it sounds unreal up close. I actually am going to have to order different mufflers. Exactly like the ones I have but these are damn near hollow, more like resenators than actual mufflers. Its just too load. I love it but if its above 98 or pushing 104 DB it might sound great but your not going to get any track time around here. Well you might get a few laps before you see a big black flag.

 

Drove it around the industrial complex today to check the suspension set up I had done. MTI Racing did it for me. They are the ones who built the motor. Its got so much damn power listen to it bark the dyno in 3rd. To say that it is going to be a blast to drive on the track is an understatement. We had a pool at the shop. Everyone put in $5 and you guessed the weight of the car w/o driver. Well I didn't win but Doug Wilks hit it damn near on the money. The final tally..............2,248lbs. Doug guessed 2,250.

 

635Hp. 603Tq.

 

Link to Video:

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Huge numbers... And how the hell did you get that thing sooooo light? WOW... Mine is a pig. We're still above 2600 even with all the work done to lighten it with component swaps...

 

I need to get mine on a generous dyno for some mega numbers...

Congrats!

Mike

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