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Carbon, carbon, and more carbon! Trying to get to 2800lbs.

AJ Hartman

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Its been years since I've see/heard anything but some of you may remember Paul Birds build. A 95 Cobra built for AIX and aiming for 2500lbs. That car inspired me to start tinkering with composites. My background of body work definitely helped me get up and going pretty quickly, but there is always something to learn, new techniques to try, new materials, and on and on and on.


So a quick background... I started this car back in 2009. Original build thread is here: viewtopic.php?f=3&t=30395&start=80. I'll skip everything up to this point as not a whole lot was done. I won the Northeast American Iron Championship in 2013. Took a bit of a hiatus to focus on the business in 2014, but am going for a good run again this year. I had a little bit of an incident the first race of the season so decided to pull the trigger on a project I've been thinking about for a year or two. I will be turning the whole car (withing the rules of American Iron) into carbon fiber.


So here is the car as it sat for 2014.

17073343697_49e46c1ff3_b.jpgmycarwlogo by aj.hartman62, on Flickr


Updates as of 2015 were a hood vent, and swan neck wing custom built by myself.

Here is initial mock up. Didn't have time to stress test the uprights so I'm pretty sure I made them over kill. Second itteration will happen later.

17279010122_a0cdd6d1a1_b.jpgUntitled by aj.hartman62, on Flickr


Finished up

17254808686_16b8d684bf_b.jpg10983365_976758299003189_1997495607814806300_n by aj.hartman62, on Flickr


Hood vent

16725035379_3d7b774120_b.jpgIMG_3058 by aj.hartman62, on Flickr

16291204703_c50eb9857d_b.jpgIMG_3057 by aj.hartman62, on Flickr


As you can see, carbon has been creeping onto my car ever so slowly, but now its time to go nuts. I know, everyone is thinking why not just add more power, but that would be to easy.



After my incident during sundays race which resulted in a smashed fender and bumper, and some suspension damage, I decided to move ahead with turning everything into carbon, especially with the car putting on weight due to the addition of a MM torque arm and PHB. (Note: I absolutely love the stuff, works great, but is obviously heavier than the stock 4 link. Yes, I raced since 2010 with a 4 link).


So my plan for this thread is to post updates, answer questions when and if I can, and do things like post weigh savings over stock stuff, or gutted OEM parts, etc. Maybe some race updates as well. I also like to try and validate anything I do with AiM Data or atleast a simple wool tuft test, or oil drop test. Also, the thread may help keep myself motivated to get things finished!


So to start, went to a local you-pull-it and got two doors, only had FL fender, and all the roof trim pieces. Got the initial drivers side cutting and mock ups done. Will have to find a FR fender and repeat on the right side, then its body work, then prepping to be moulded and moulding time. Heres where I'm at at the moment. Might be a little hard to see the finished product at this stage. Keep in mind, I'm just making the plug so I utilize certain techniques that may make the moulding process quicker/easier. A relief will be cut into the fender, but will make future steps much easier with the large side panel at the moment. I also cut in the doors a little bit to help smooth the radius of the tire relief.


17280520931_ecebf00bb4_b.jpgIMG_3125 by aj.hartman62, on Flickr


17255052786_349f4d0c56_b.jpgIMG_3124 by aj.hartman62, on Flickr


My theory behind the fenders follows a nice article I read on the new crop of BTCC cars and their fenders. The simple mechanism is getting rid of any downward slope aft of the front tire which would cause lift and drag. A run in the wind tunnel of the Mercedes in that series proved a decrease in drag AND and increase in Df. There are very, very few situations where this happens.


Anyway, thats about it for now.

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Not a big update but all the plugs are done, both doors, both fenders and trunk. Heres a quick pick of passenger side. Just hung the stuff real quick to make sure I wasn't way off but didn't take the time to get a good gap. Finally onto the flanging and moulding stages.


17127959990_69719a0a33_b.jpgIMG_3132 by aj.hartman62, on Flickr


I've started taking preliminary weights and my original doors which were gutted to the max were still 28lbs. I estimate the carbon doors will be about 7-8 each so will save almost 40 there. I should save another 10-12 between the fenders, and trunk should be another 15lbs. So I'm estimating a 65lb weight savings between these parts. I've removed some other weight from the car so should be close to 75lbs lighter by next race, if I get all the parts done in time.

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Flanged, gel coated, and fiber glassed. Now I wait. The fenders and trunk are done as far as fiberglass goes. I didn't have enough resin on hand to finish the doors but got 2 layers down. These are not "production" moulds so are not built to pull tons of parts all day long. This allowed me to speed up the process somewhat. Still, I was laying down fiberglass for about 12 hours today. Tomorrow is a fun day, like opening presents on Christmas, as I get to demould the trunk, and both fenders and do all my trimming. Since the doors can not go any farther that may allow me to even polish the fender and trunk mould but we will see. Thats a day or two process in itself sometimes.


17150075788_ba3f8e3ff4_b.jpgIMG_3141 by aj.hartman62, on Flickr

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Finally made some progress. I finished the tedious time consuming steps of preping the fender and trunk moulds. The second fender is curing as I type this but got the passenger side demoulded and trimmed. Trunk is laid up but have to wait for the fender for cure to use the oven for that part. Pictures of that will be in a day or two. I'm in a crunch to get some things done for the NASA NE event this weekend.


So some weights. OEM fender as is is 11 lbs. The fenders on my car were 8.5 as I trimmed some excess flanges and stuff, and the louvers actually removed just over a pound as they are lighter than the metal they replace. New carbon fenders are 3.5lbs. So a savings of 10lbs off the nose, but more importantly is the aero advantage in this instance. I removed my trunk, which I pretty much gutted as much as I could and it is still 22lbs. The new one should be in the 5-6lb range so a savings of 16-17lbs there. Not huge numbers since they were already gutted but I'll be pushing 30lbs lighter along with better aero. It all adds up!


Some pictures.

16960347583_9a46971df0_z.jpgIMG_3176 by AJ Hartman, on Flickr


17393094070_89e37374bc_z.jpgIMG_3178 by AJ Hartman, on Flickr


16958121324_2a0ac25c96_z.jpgIMG_3179 by AJ Hartman, on Flickr


17580688415_aa93855ca4_z.jpgIMG_3180 by AJ Hartman, on Flickr


17394337829_b82b925140_z.jpgIMG_3181 by AJ Hartman, on Flickr


I will eventually make a rear liner to smooth the transition to the outside as this will help evacuate air going under the splitter and through the radiator. Thats about it for now. Pictures of it together completely will happen next week.

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Finished the trunk just in time for last weekends event. Trunk came in at 5.5lbs so saved about 16lbs from my already gutted stock trunk (would be close to a 30lb saving over a not gutted trunk). I'm very happy with the results. I ended up using dzus's to hold the trunk closed instead of something similar to hood pins just to keep it clean looking. There are provisions on the trunk to mount up to the stock hinges, but its not a full finished underside for weight reasons. Thats why the dzus's or pins are needed.


17642425050_dee52d8c87_z.jpgIMG_3183 by AJ Hartman, on Flickr


17643718869_7ebe0d8996_z.jpgIMG_3182 by AJ Hartman, on Flickr


17829913275_b1edf9c84e_z.jpgIMG_3191 by AJ Hartman, on Flickr


17209544753_8cda00b915_z.jpgIMG_3190 by AJ Hartman, on Flickr


Picture of the front with the fenders all mounted and louvers reinstalled.


17642362390_56a003a227_z.jpgIMG_3189 by AJ Hartman, on Flickr


17209546073_8f1708b37a_z.jpgIMG_3188 by AJ Hartman, on Flickr


Someone asked me about my weights and cornerbalance numbers. Keep in mind I am on conventional springs, and do not have the adjustable perches in the rear. I'm pretty much limited to shimming, or turning the pig tail of the front springs to get "close enough". These are by no means awesome numbers, but they are what they are for the time being. My concern at the moment was total weight. Picture is with just over a half tank of gas, and me in the driver seat. Post race I came in at 2947lbs.


17642098238_d98466d112_z.jpgIMG_3184 by AJ Hartman, on Flickr


The races weren't bad. I finally got a dyno so I now know for a fact that I am 60hp short of what I am allowed to make at this weight, or about 500lbs heavy. I was .040 seconds from getting the pole on Sundays race. I got some bad luck in traffic and slipped back a position and from then on I could hang with the front runners, but couldn't get a run on them and pretty much played follow the leader the rest of the race. Given that, I think I'm still making a point that lightness and aero are a decent combination.


My Monsterous power numbers!!! Now you can see why I'm trying to loose weight.


17383800503_e1c4613852_z.jpgIMG_3186 by AJ Hartman, on Flickr


So next on the list, the doors are still halfway done so will keep moving with them.


(Note: Post race I went over my data and for sure am headed in the right direction. The car is definitely getting more "slipery". Same power numbers as my last outing there in 2013 but with the new wing, fenders, and a few other tweaks I was able to pick up on average 3-4mph on the straight.)

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AJ, you da man! Keep developing!! I, too, have one of these cars that's involved in a slow, log-term build so I will be following closely as I may be interested in these pieces if you ever decide to reproduce them for the market... Keep on truckn'!!



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  • 2 months later...

Picture time! I had an awesome weekend at LRP for NASA NE's 4th of July event. Set the lap record. But by the pictures, you can see that it didn't end up all that great. Heres the link to my blog about how it all happened. http://www.ajhartmanracing.com/blog/


and the video:



19729488456_63a9b4c935_z.jpgIMG_3306 by AJ Hartman, on Flickr


19567640808_63c85390d6_z.jpgIMG_3307 by AJ Hartman, on Flickr


19567646310_eef0fd338a_z.jpgIMG_3308 by AJ Hartman, on Flickr


19133088594_f9f9c09b8f_z.jpgIMG_3310 by AJ Hartman, on Flickr



So heres where I'm at now. The plug for the front bumper is almost done. I opted to shave the upper and lower grill. This should allow me to do several things. Mostly it will be much easier to add any brake ducts as necessary (as opposed to the brake duct/fog light hole area) and you can adjust your grill opening and make a tighter, nicer radiator ducting (efficiency).


19729486696_ff1634a49b_z.jpgIMG_3336 by AJ Hartman, on Flickr


19748423272_6884a5a93c_z.jpgIMG_3337 by AJ Hartman, on Flickr


Right now my hope is to be ready to NASA Nationals at VIR, but we shall see. Still a TON of work to do.

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So, finally a car update. I got the bumper plug finished and flanged and in gel coat. The door inners are in gel coat as well but no picture. Onto fiberglass tomorrow. I'll snap some pictures of the moulds, and then some more once I get around to demoulding them. The picture is how a part should be flanged and gel coated after properly applying mould release.


20062798052_20215fe8ff_b.jpgIMG_3362 by AJ Hartman, on Flickr

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  • 4 weeks later...

So some updates finally. Door molds are done. Bumper mold is done. Neither parts are made tho as I've been busy keeping up with other stuff around the shop and even tho I make the parts myself, the materials are still pretty expensive and time consuming to do. Once the front bumper mold was done that allowed me to move ahead with making molds for the front bumper canards. Below are some pictures of the aluminum plugs and the finished parts.


20574047100_b20cb5a233_b.jpgIMG_3393 by AJ Hartman, on Flickr


20735765816_629ec42eba_b.jpgUntitled by AJ Hartman, on Flickr


20574040718_0ab5101c11_b.jpgIMG_3395 by AJ Hartman, on Flickr


20141060473_2d690f5221_b.jpgrg4tgr by AJ Hartman, on Flickr


Heres the mold of the bumper cover. A few posts above is a picture of just the bumper with the gel coat on it. I purposely made the flange beyond the built in "splitter" large enough to be able to have a finished top side to an American Iron legal splitter size. Still not 100% sure thats how I will do it tho but the option is there. Once I build the splitter I'll do whatever seems to make the most sense. With the shaved upper and lower grills, I'll be able to do something pretty slick with the radiator and ducting associated with that.


20139438454_fc6176ccb4_b.jpgIMG_3434 by AJ Hartman, on Flickr


Thats about it for now. I am definitely not making Nationals, but still want to have the car ready for a race or two at the end of the season. Bumper should be done soon ish, then onto the splitter which I'm excited about. I'll be doing something never seen before on a Mustang (atleast I've never seen).

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  • 2 months later...

So its been a while since I updated here. The shop got busy, which is good, but I haven't had much time to do anything to my own car. I missed nationals, and the last few events in the North East region. I was able to get the front bumper cover on and very loosely mocked up to the car. So don't mind the gaps being a little wonky, as once its properly mounted it will line up nice. Now that the bumper is done, I can get to work on the splitter. And yes, the splitter is allowed to be bigger than the lip that is already part of the bumper. Thats where some of the really trick stuff will happen. Bumper is only 9lbs so I'm happy with the weight for the size of it. The super flimsy fiberglass one I used to make the mold was 16 if I remember right. Heading into the "off season" I hope to get the splitter, diffusor, and side skirts done. I want to do some suspension work as well, and then hopefully get some power in this thing!


The other kinda cool thing is that I was offered the position as the NASA NE American Iron Director. So now I HAVE to make sure the car is ready for every event.


22203932460_bf38eb9f94_b.jpgIMG_3510 by AJ Hartman, on Flickr


22402706931_01132e5934_b.jpgIMG_3509 by AJ Hartman, on Flickr


21770830223_9b4d69f7ba_b.jpgUntitledergerfg by AJ Hartman, on Flickr


21770829203_be5d36068f_b.jpgUntitled by AJ Hartman, on Flickr


22365938916_7afca3bdd7_b.jpgIMG_3492 by AJ Hartman, on Flickr

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