Looking for a few good candidates (And their money)

[cobramatt]

  I didn't mean for this to be a hostile exchange.    And it's pretty easy to see who you are, after all you made a video of a race day. A lot easier for me to see who you are than you to see who I am.

 

You described what a diffuser does, I already know that. You've asserted that the ones you've seen (at the track) don't work.

 

My questions, that you haven't answered, are, why do they not work, and what would it take to make them work?

 

I just love it though, and it really feeds my drive to succeed at something, when someone says something won't work or I don't know what I'm talking about. So keep it up, it has positive effects.

 

I've been building cars from scratch for 25 years. I was wrenching on Z's before you had a drivers license. I don't know why these aftermarket or scratch pans and diffusers don't work and I was asking someone I thought might know. But even race car drivers don't know everything I guess. That's disappointing, I thought they were omnipotent.

 

That's okay though, I'll figure it out one way or another.

 

I invested in Solidworks (with CFD) a long time ago. Pretty sure I can dig up a s30 solids file. I'll spend some time with the Z aero and get back with you guys.

Chris,

If you are proficient in solid works that means you are more than likely a mechanical engineer. If you have been wrenching on Z's before I had a license that would make you around 55 to 60 years old. Given that you have all this experience you don't need my omnipotent race car drivers input anyway. I guess its just the immature way you post, your verbiage skills, the fact you don't read very well or it could be the fact you don't really understand what I'm trying to say to you. I never said that the diffusers (AT THE TRACK) that I see don't work. I am discussing our cars. 240Z's. Thats why I'm posting on HYBRIDZ. I have never seen a 240Z with a properly designed and functional underwing and diffuser. EVER. I have seen and driven plenty of modern race cars (AT THE TRACK) with perfectly balanced undertrays and diffusers that work just fine. Question for you.....Do you think you can take a modern race car undertray with diffuser and remove it from that car and attach it to the underside of a Z and it function properly. With all your experience wrenching on Z's I would have guessed you said yes given your previous posts. This of course is incorrect. It doesn't work that way. You say I've "asserted" that the ones I've seen at the track don't work. That is not what I said and Mike Kelly tried to point that out to you as well but you still insist that is what I said. For the record...........I said, ( I see loads of people who attach panels to the underside of a car, I see people buying diffusers all the time and not actually realizing that they are not doing anything but adding weight and drag to the car). Thats copied and pasted from my post. I am referring to the idiots who try and make their cars look like a race car but have in actuality caused more weight and drag thus it actually works against them. The design of a diffuser actually begins with the splitter and nose of the car, but you probably already knew that. I remember now, you dont ever want to race but might want to go fast someday and you wanted a functional underbelly and diffuser for your Z to be able to fully take advantage of the aerodynamics. Given that I'm 50 years old and omnipotent I'd say you better hurry up and get busy goin' fast. 

Edited June 12, 2013 by cobramatt

[cobramatt]

  I didn't mean for this to be a hostile exchange.    And it's pretty easy to see who you are, after all you made a video of a race day. A lot easier for me to see who you are than you to see who I am.

 

You described what a diffuser does, I already know that. You've asserted that the ones you've seen (at the track) don't work.

 

My questions, that you haven't answered, are, why do they not work, and what would it take to make them work?

 

I just love it though, and it really feeds my drive to succeed at something, when someone says something won't work or I don't know what I'm talking about. So keep it up, it has positive effects.

 

I've been building cars from scratch for 25 years. I was wrenching on Z's before you had a drivers license. I don't know why these aftermarket or scratch pans and diffusers don't work and I was asking someone I thought might know. But even race car drivers don't know everything I guess. That's disappointing, I thought they were omnipotent.

 

That's okay though, I'll figure it out one way or another.

 

I invested in Solidworks (with CFD) a long time ago. Pretty sure I can dig up a s30 solids file. I'll spend some time with the Z aero and get back with you guys.

Edited June 12, 2013 by cobramatt

[Chris Duncan]

I'm here to gain knowledge, that is all.

 

I learned a few posts ago that you can't just "bolt on" an undertray and diffuser and expect it to work. I had suspected that already.

 

I was asking why, and what needs to be done to make it work, that's all.  I meant no disrespect but I think you took it that way.

 

I still don't have an answer...

[Mikelly]

Here is a novel idea, if you don't like the agenda of those who are spending their time and money to conduct a test, and willing to share the data, then DO something constructive to contribute to the Zcar community yourselves. Otherwise, when you get pushback, think about WHY you are getting it. Chris I don't know or give a good goddamn about how old you are. I am 46 years old and have never claimed to be an engineer.  I have repeatedly stated that I listen to "true" experts, of which one person in this thread qualifies for based on real world first hand experience.  The points being made are when its your money tilting windmills is fine. Dont crtisize us because we choose not to ignore smarter peoeple than those in this thread.

There is an excellent laypersons explanation of what doesnt work with rear difusers in Junes GRM. An "expert" wrote that article, but as this thread has proven, his advice will likely be ignored too. Good luck with your software tests and finding a solidworks 240z model. Burton Brown has been looking for one for a while.

 

 

Now, since we keep getting asked "But why" (and I'm having flashbacks to my kids at 11-13), Maybe it has to do with the simple facts that the 40 year old Datsun Chassis is, well OLD, and designed 40 years ago.  Look at the fender openings and where the suspension uprights sit.  Where is the fuel tank located?  Notice how FAR BACK it sits behind the rear axle?  Look at how uneven the floor pans are.  What cars have you owned that have excellent aerodynamics?  I've got first hand experience with the most recent Corvette platforms, and both employed cab forward designs parking the wheels into the corners and minimalizing overhang.  Both employ saddletanks that rest in front of the rear wheels.  Both utilize complex shapes to help aid not only suspension and subftrame design but the designs of the fenderwells/liners to assist in clean aero, ALL before considing the tunnel for the driveline or the floor pans, which are, you guessed it, FLAT. 

 

 

Now lets move on to the Porsche.  One of the most sopisticated platforms made.  I've torn appart TWO of the most current 911s of the last decade, the Twin Turbo and the GT3.  Having owned both, I was intimate with their design.  Having converted the Twin Turbo to FULL FACTORY FUNCTIONING GT2 AERO, I can tell you with a great deal of confidence that they too exercised much of the same elements used in the C5/6 Corvette in designing the chassis for the task, only taking greater steps to incorporate those designs.  Aero channels starting just behind the nose and incorporated in the front closeout panel, air guides and diverters, vents and scoops built into the fender liners and other undercar panels... Google Mikelly and 996TT and you'll find the work done, and much like my Zcar pics, PLENTY of documentation. 

 

http://www.renntrack.com/forums/showthread.php?2227-FUNCTIONAL-GT2-Bumper-Conversion-DIY-Facts-Fiction-Broken-ankles-oh-my!&highlight=Mikelly

 

THOSE MANUFACTURERS DESIGNED THE CARS TO FUNCTION with ACTIVE AERO.  Datsun didn't in 1969.  That porsche Turbo was the car the windtunnel engineer pointed to as reference to what would be required to get  a Zcar to function like, well a POrsche.  His comments were something like this "Better off spending your money on one of those.  It'll save you the time of trying to recreate it."  I'm sure Mortensen can dig up the exact quote from somewhere, as he seems to need to prove I am foulable.

 

You guys want to create something that was unintended, and you can't just accept that "MAYBE" something won't work on the vaulted S30 chassis.  I love the Z.  It's why I still have it and all those other cars are long gone.  But I am a realist.  I know its limitations are somewhere below the basic platform of any host of other platforms.

 

 

Now, onto your jab at Matt Isbell for his video.  That's a pretty cheap shot and quite honestly, if he won't comment on it, I will.  I was SPONSORED by vendors for doing DEs in my Porsche.  Given parts to use, parts at huge discounts, or parts to evaluate and send back.  For DEs.  Matt is racing in NASA and winning nearly everything he enters, wheel to wheel.  You ever stop and think that marketing his talents might land him a seat in a pro ride?  Of course not, because it is to easy to look too shallow and assume this is a guy who is bragging and "look at me"... If you aren't a businessman or don't have an understanding of marketing in motorsports, you'll never understand how it is that I got porsche parts sponsors to give me high dollar porsche parts for free or at/below cost, or why a guy like Matt Isbell made a movie about his "day in the life" of a club racer.  And since you don't understand any of that, I guess it comes as zero surprise why the hell the issues around aero and flatbottoms on Datsuns is a HIGHLY unlikely successful venture.

 

 

I'm done justifying my efforts in getting some of the most developed Zcars in the country into the tunnel.  Those who want to participate can contact me offline.  Those who want to argue and be the smartest guys in the room can have this thread.  And as usual, run it into the ground.

 

EDIT:  NOW I'm DONE, and I've used the F'N ignore feature on this board for the first time.  No more Smartest guy in the room posts!!!

Edited June 11, 2013 by Mikelly

[JMortensen]

Yesterday was a false alarm, for the record. Just a few more questions before you go Mike. I read that GRM article too. What materials did he suggest making a diffuser from? Did he say anything about needing CFD or tunnels or any other extravagant methodology to make one? How did he compare the Vette diffuser to the Civic diffuser that looked like it was built in a garage? Most importantly, is the author right because he is an expert, or is the guy at the windtunnel right because he is an expert? 

Edited June 11, 2013 by JMortensen

[roger280zx]

Hey Matt that's a sweet vette, testarossa, caddy, maxima you've got there.  But on a serious note, I saw an Audi that was fast, really really fast... it had an underbelly, rear diffuser, AND a diesel engine.  Does that mean that if I put a diesel engine in my 240z that it will be faster?  Just like the Audi? 

[roger280zx]

Seriously though thank you for all the input.

[cobramatt]

Seriously though thank you for all the input.

Rodger,

 

Thats my new daily driver and I'm glad you like it. I did that with plywood, cigarette smoke and a floor fan in my garage / wind tunnel. I am pretty sure it works because it looks really cool and I get a lot of looks. It seems I'm getting terrible gas mileage now for some odd reason but "heck" was thinking maybe I wanted to go fast one day and I just wanted to know I had functional aerodynamics on my car. Its a flat bottom as well.

 

About the Audi........If it said R18 on the side then you are correct. It is very very fast, very very quiet, very very expensive and very very exclusive unless your name is Alan McNish. This guy by the name of Dr Wolfgang Ullrich has made a living by winning LeMans every year and all he does is hang plywood under a car and see if it works. It can be hung relatively anywhere under the body and I think he is moulding his diffusers out of cardboard. Amazing stuff............I wonder if we could do that to one of our cars? If you ever do put a diesel Audi engine in your car, the undertray and diffuser come with the kit, you just bolt it on.

 

You are welcome for the input and I will continue to try and forward our cause and push the boundaries of what we thought was possible. How are my old wheels you bought from me working out? Do you ever run them? 

[roger280zx]

The wheels are garage jewelry until I get the chassis done. The injectors are off getting cleaned and flowed. And the damper will go on when I swap the new cam in. Hopefully all done by end of summer. Just trying not to set her on fire for the time being. Your ride has come along nicely btw. Let me know if you decide to do the pinstripe as I have black vinyl and the last ever "stripe cutter". Sorry for the off topic guys...

[cobramatt]

The wheels are garage jewelry until I get the chassis done. The injectors are off getting cleaned and flowed. And the damper will go on when I swap the new cam in. Hopefully all done by end of summer. Just trying not to set her on fire for the time being. Your ride has come along nicely btw. Let me know if you decide to do the pinstripe as I have black vinyl and the last ever "stripe cutter". Sorry for the off topic guys...

I forgot about all the items I've sold you. If you want to come to Road Atlanta this weekend and watch the car in action, there will be lots of people and lots of cars, I think our race has 50 cars. It will be a very big show and would love to have you out. Don't worry about being off topic on this thread as I have forgotten what the topic is anymore, so no worries. 

[Chris Duncan]

""There is an excellent laypersons explanation of what doesnt work with rear difusers in Junes GRM. An "expert" wrote that article, .....Good luck with your software tests and finding a solidworks 240z model. Burton Brown has been looking for one for a while.""

 

""Now, since we keep getting asked "But why"""

 

When I stop asking "but why" I stop learning.

 

 ""Maybe it has to do with the simple facts that the 40 year old Datsun Chassis is, well OLD, and designed 40 years ago.  Look at the fender openings and where the suspension uprights sit.  Where is the fuel tank located?  Notice how FAR BACK it sits behind the rear axle?  Look at how uneven the floor pans are.  What cars have you owned that have excellent aerodynamics?  I've got first hand experience with the most recent Corvette platforms, and both employed cab forward designs parking the wheels into the corners and minimalizing overhang.  Both employ saddletanks that rest in front of the rear wheels.  Both utilize complex shapes to help aid not only suspension and subftrame design but the designs of the fenderwells/liners to assist in clean aero, ALL before considing the tunnel for the driveline or the floor pans, which are, you guessed it, FLAT.""

 

""Now lets move on to the Porsche.  One of the most sopisticated platforms made.  I've torn appart TWO of the most current 911s of the last decade, the Twin Turbo and the GT3.  Having owned both, I was intimate with their design.  Having converted the Twin Turbo to FULL FACTORY FUNCTIONING GT2 AERO, I can tell you with a great deal of confidence that they too exercised much of the same elements used in the C5/6 Corvette in designing the chassis for the task, only taking greater steps to incorporate those designs.  Aero channels starting just behind the nose and incorporated in the front closeout panel, air guides and diverters, vents and scoops built into the fender liners and other undercar panels... Google Mikelly and 996TT and you'll find the work done, and much like my Zcar pics, PLENTY of documentation. ""

 

http://www.renntrack...ghlight=Mikelly

 

""THOSE MANUFACTURERS DESIGNED THE CARS TO FUNCTION with ACTIVE AERO.  Datsun didn't in 1969.  That porsche Turbo was the car the windtunnel engineer pointed to as reference to what would be required to get  a Zcar to function like, well a POrsche.  His comments were something like this "Better off spending your money on one of those.  It'll save you the time of trying to recreate it.""

 

thank you Mike Kelly

 

FINALLY SOME REAL INFORMATION. Instead of insults and name calling, how refreshing. I knew if I was persistent I would get somewhere.

 

 

""You guys want to create something that was unintended, and you can't just accept that "MAYBE" something won't work on the vaulted S30 chassis.  I love the Z.  It's why I still have it and all those other cars are long gone.  But I am a realist.  I know its limitations are somewhere below the basic platform of any host of other platforms.""

 

I will accept it as soon as I have access to the facts so I can analyze them. I want to see for myself, that's the way I learn. I apologize if that is different from somebody else, or if you thought I was trying to be insulting.

 

 

""Now, onto your jab at Matt Isbell for his video. ""

 

I'm sorry if you misunderstood me. I never took a jab at his video. Go back and re-read please, all I said was that it is easy to get an idea of what kind of person he is because he has posted a video of his racing. I actually think it's a well done video of an exciting lifestyle. 

 

""And since you don't understand any of that, I guess it comes as zero surprise why the hell the issues around aero and flatbottoms on Datsuns is a HIGHLY unlikely successful venture.""

 

I raced enduro go-karts as a privateer for 5 years back in the '80's and was friends with guys who were partially sponsored, I have somewhat of an idea how difficult it can be.

 

 

[JMortensen]

http://clubroadster.net/vb_forum/89-roadster-projects/44470-my-na-becomes-track-car-build-thread.html

 

Long read. Worth it.

[JMortensen]

 

 

 

 Let me assure you that an engineer or aerodynamicist has never in the history of time just attached some plywood to the underside of a modern race car to see the data in a wind tunnel, when they use cad programs to design every piece on the car and simulate the aero in a virtual tunnel before they fabricate exactly the under-tray that is ultimately the best treatment for the car given the data supplied prior to ever even fabricating the first piece on the car.

 

 

Saw this picture, so I thought I'd ask you. Matt, do you know where to source this PLYWOOD GRAINED carbon fiber? Was hoping to get some to make the splitter for my car.

Edited August 8, 2014 by JMortensen

[Tony D]

I'm 50, and I reiterate the question I posted earlier: Is there any plans of testing the original Nissan G-Nose undertray? Burton Brown and I have been conspiring to try and get one out of Japan this entire  past year. Given the 280ZX aero testing, this tray was part of the G-Nose Package that decreased the original S30 Cd down to the 0.38 range. 

It's a fitted FRP Piece, which has been faithfully reproduced from an original G-Nose Piece and is sold for around $400 in-country. One trip to Japan back to LA with Business Class Luggage Allowance would get several back in-country for replication and testing.

 

I'm always up for assisting furtherance of knowledge, and would love to supply the part (or donate $$$ again) to see what it does. Actually, having a working aerodynamicist at the site may be of assistance, can I get a partner to split that stated fee? I don't know if it would be better than the tunnel operators comments--but in understanding what the air was actually doing (as Matt wants to understand) it may prove very valuable. It just depends on who is that curious. Who else spend $184 on "Turbocharging the Internal Combustion Engine" back in 1984? LOL

 

As for 'flat bottom' there is a class in LSR that could use it---if it were beneficial. We used one, it may have helped...hard to say as it's combined with front-end blockoffs to make 'the class'.... Doing it on it's own, and then piece by piece adding the parts up front may indeed reveal that it was the combination of blocking air inlets up front that gave the speed increase, rather than a smooth bottom.

 

The concentration for me and Burton is to quantify the advantage of using that G-Nose part (undertray to mid-transmission) as it would be allowed in GT and PRO classes as a stock piece. NOBODY to my knowledge has EVER used one here in the USA. It was in the parts books of the day, but never made it over into the motorsports catalogs as it appears people were more interested  in the 'cosmetics' than in the function of the total package that was the G-Nose (as proved out by testing in the first series of tests with the One-Piece G-Nose!

 

Old White Guys arguing over 160+ mph Z-Cars. Somewhere, on some Honda Forum....we are  excoriated as being the Devil because of how fast we actually go, and how we argue over actual applications, and not theoretical flights of fancy...

 

All this being said, Andy Flagg is selling the Bonneville G-Nosed Z. There's a rolling adjustable height car for you, albiet on the wrong coast. With the departure of that vehicle from the immediate stable, concentration will be on the S130's I have stashed for LSR...which start at 0.38 Cd...about where ultimate development by Nissan stopped with the S30.  After that, like Matt stated, "How the air is moving over the car" starts becoming your focus for incremental gains which are not allowed in the LSR classes but are on Road Racers.

 

As always, let me know what I can do to assist or where to send the $$$ if necessary. 

Edited August 9, 2014 by Tony D

[roger280zx]

Well ^^^^ that is not Matt's car, Matt didn't make the splitter for that car, glad to know some folks still can't let sleeping dogs lie. 

 

Tony, I would love to know more about these s130 lsr cars.  Was the s130 gnose a factory developed part?  Those of us who were born in the "Nissan years" after '83 who only know the aritaspeed gnose (and some state side version of it) and are inquiring on its benefits before we go coo coo trying to find one!  I do have the original Kaminari air dam (that came with the car) which is nice because it has lots of big holes that can be easily ducted/blanked.  But I really am trying to understand how the air gets around that protruding bumper and over that huge hood.

[Tony D]

I don't think the Arita Speed S130 G-Nose is anything more than cosmetics appealing to nostalgia.

 

The original testing here revealed the G-Nose to "not be all that" but it was based on a replica. The MSA Typ3 was found more beneficial as I recall (after modifications that made the radiator ducting similar to a real Nissan G-Nose.)

 

It was at that point I grew curious.... Since making small cardboard extensions to the trays directing airflow made such an efficiency difference on the MSA, what would the similar differences be for the aftermarket G-Nose (compared to a properly replicated or original unit), and consequently with the blunt-nose under tray which Nissan cited as critical in their Aero Testing of the S30 in development of the S130.

 

The only S130 Aero Mods I know of from Nissan is the front Air Dam from JDM/Euro Turbo models, which was combined with a very trick plastic duct that sealed the inlet to the radiator directly...much like the ducting used on earlier S30's to prevent leakage around the radiator (and would accomplish that dual purpose mentioned earlier of preventing air under the hood from an unsealed hood to front upper radiator support--all air in the front of the car is channeled through the radiator.)

 

From that duct, it looks that they tried to make it a semi-bottom-breather taking anything below the bumper either through the radiator or around the front...and anything above the bumper over the top (which seems to be validated by the downforce attained from installation of the G-Nose to the S30)

 

Recall I'm saying a class exists that would allow it. And we did try it. But there is no way to quantify wether plugging up the front of the car is what gave our increased top speed...or the belly pan. I would tend to think Matts comment that it may well not have contributed could be warranted. We plugged the front end up, and in that same configuration but without the belly pan...speeds were similar if not higher.

 

This is why the curiosity exists on the S30 G-Nose and Undercover. It is a legal production part, so if placing it on the car foes affect Cd, it may be more productive to run it only, as opposed to the "grailistic, mythical flat-bottomed magic silver bullet"

 

I only wish I'd been successful in obtaining one this year to be able to make it available for testing.

 

Since the S30 is being sold...and I have S130's with better aero out of the box compared to S30 terminal development...we likely will press forward on them with S30 stuff remaining an idle curiosity channel which I will gladly help fund to satiate said idle curiosity.

Edited August 10, 2014 by Tony D

[jt1]

Just to confirm, the gnose we tested in the tunnel was a repro, the lower valence was not sealed back to the radiator support, it didn't have a air dam or spoiler, and had no headlight covers.

 

Not a full test of the gnose, but it was all we had at the time.

 

jt

[Tony D]

Fully Understand... The documentation made that clear from the start as well.

We're all hamstringed by lack of personal Transport Pods to zap parts transcontinentally (or Trans-Hemispherically in my case!)

 

So, we do with what we have. From the MSA Type3 results, it becomes clear the reproduction G-Noses are more "cosmetics" than the Originals Nissan made. Good luck finding a complete one to test...

 

Highpoints of that test was MSA altered their air dam based on the testing completed. Bravo!

If only the One-Piece G-Nose replicators would follow suit for better effect to the Z-Community.

 

I'm not complaining by a LONGSHOT---the data gleaned only whetted my appetite to be sure!

[HS30-H]

As a fan - and owner - of Nissan's 'HS30-H' model Fairlady 240ZG, I'm always surprised that seemingly so few people appear to understand what it was, and what it was actually for...

 

The 240ZG - as sold to the general public - was purely an homologation model. It was built and sold to the general public purely as a means to legitimise and legalise certain aerodynamics-related parts that Nissan wanted to use in FIA and JAF Group 4 (and 5) racing classes. Having built and sold a certain number (or - as Ferrari often did - claiming that they would build a certain number of them) the FIA and JAF allowed those parts to be used on race cars in the relevant classes.

 

The parts fitted to the road cars were just a base that was intended to be built upon. Nissan certainly never intended the 'Grande Nose' to be used on its own. It was designed to be used in racing with a splitter/spoiler, and with an undertray/belly pan and full ducting for the radiator opening, radiator support panel and front brakes. None of these parts were practical for use on a standard road car, and were not necessary for the homologation anyway, so they were never fitted to the road cars. 

 

Nissan's works race team developed and updated this aero package during the 1971~73 period, and many of the parts used on the works race cars were made available to the privateer racer in Japan through Nissan's own 'Sports/Race Option' parts lists.

 

Not only are most of the so-called 'replica' G-noses that have been sold over the years nothing like the genuine article, but they are not even being used as Nissan intended - as a base on which to build a more complete and effective package. I brought this point up on the previous wind tunnel testing thread, but it still gets overlooked.    

 

 

 

This is why the curiosity exists on the S30 G-Nose and Undercover. It is a legal production part, so if placing it on the car foes affect Cd, it may be more productive to run it only, as opposed to the "grailistic, mythical flat-bottomed magic silver bullet"

I only wish I'd been successful in obtaining one this year to be able to make it available for testing.

 

 

Tony,

Here's the factory 'Under Cover' for my 432-R replica project car, a part that existed from 1969. It can be bolted onto the G-Nose's lower panel as it shares the same mounting points:

 

 

Edited August 10, 2014 by HS30-H

[HS30-H]

Just for interest, historical reference and....... fun:

 

A few frame captures from film of the S30-series Z's engineering development in 1967/8, showing both scale model and full size wind tunnel experiments: