GTM roll cage modifications and race car build log

[kabacj]

awesome progress, when's the next track day?

That all depends on how quickly I can get the transaxle back into adjustment

Maybe as soon as June 5, but since I was unable to get the endoscope into a position where I could see anything wrong. A tear down is planned for this weekend. Lots of family stuff planned too so it's going to be a difficult task to fit in.

Maybe I'll just forfeit sleep to get it done.

[kabacj]

I got a several pictures back from my weekend at VIR.

This is one of the shots I like.



The thing I like most is the amount of daylight under the inside tires.



I still have adjustments to make, but the handling is neutral now and keeps getting better as I tune it.

[kabacj]

A few more pictures from my last weekend.

[kabacj]

After getting through a long list of non GTM home improvement projects it's time to get back to the GTM and see what's going on in the transaxle.

As usual I'm under the gun from a time perspective. One day on the weekend to work on the car and one day to pack up for Limerock. I'll leave Friday at 4am to get to the track.

No racing on Sunday's at limerock so we race Friday the 3rd and Sat the 4th. On the good side the event is un muffled so no sound restrictions. We only have a few unmuffled days a year.
The GTM is not as loud as other race cars, but I doubt the Kooks exhaust would pass sound tech without cats.

[The Stig]

One day on the weekend to work on the car and one day to pack up for Limerock. I'll leave Friday at 4am to get to the track.

No racing on Sunday's at limerock so we race Friday the 3rd and Sat the 4th.

I'm glad you're here... I get to live my racing needs vicariously through you and your posts. I look forward to reading how things work out at the track.

Be safe, and have fun!

Mike

[kabacj]

Hey Mike

Thanks for the support. Some times burning the candle at both ends I just want to take a break and relax but knowing that you guys are watching gives me the extra drive I need to get the job done and make it to the track.

Speaking of jobs that need doing.

I found my shifting problem.

It all started over the winter when I redesigned and relocated my shifter.

The mods worked really well till this little stop loosened up. (Mostly because I never tightened the lock nut)




You can see on the witness mark how it stops the shifter from moving. Well eventually The Allen head bolt backed out enough to just barely get the shift done and that's when the shift dogs start crashing together point to point and things get damaged.

Well on the good side the transaxle is a dream to work on. I have not experienced something like this since my 125 GP bike racing days. Every part of the Mendiola transaxle was made to be worked on. Every part has an obvious place to fit and no special tools or painful contortions necessary to rebuild.

In 20 min I had all the gears and forks out for inspection with the transaxle still in the car.



Ian at Mendiola who is awesome to work with sent me the one part I destroyed FEDEX and I'll have it together and working again 20 min after the part arrives.

It's really nice to work on a mechanism that was designed to be worked on. It sure is pretty in there too.

[johngeorge]

SWEET!!! good find on the shifter stop. Boy thats some shiny gears you got there. See you at Limerock.

[crash]

I tried to tell you all that these gear boxes were bordering on a work of art, but the pictures "tell a thousand words". We also, as we have stated, have found these transaxles very easy to work on. You still have to understand that the tolerances are tight and things have to be precisely put together, but the ease with which a Mendeola gearbox can be worked on in an emergency is phenominal!

Glad it was a simple fix for you. I think I called it after seeing your video of how the shifting was acting. That's because we have had the exact same issue. That is the one thing I would stress with a Mendeola gearbox in sequential configuration...that it requires precise shifter setup and if you are using cables, then a frequent attention to the adjustment so that the ratchet mechanism within the gearbox is travelled enough to do its job. If this is not done, it will cause larger issues. A little too much throw is okay. A little too little throw will cause major problems.

[The Stig]

I tried to tell you all that these gear boxes were bordering on a work of art, but the pictures "tell a thousand words". We also, as we have stated, have found these transaxles very easy to work on. You still have to understand that the tolerances are tight and things have to be precisely put together, but the ease with which a Mendeola gearbox can be worked on in an emergency is phenomenal!

Glad it was a simple fix for you. I think I called it after seeing your video of how the shifting was acting. That's because we have had the exact same issue. That is the one thing I would stress with a Mendeola gearbox in sequential configuration...that it requires precise shifter setup and if you are using cables, then a frequent attention to the adjustment so that the ratchet mechanism within the gearbox is traveled enough to do its job. If this is not done, it will cause larger issues. A little too much throw is okay. A little too little throw will cause major problems.

Race testing absolutely has it's way of defining what the common issues are likely to be. It's also great that you're both willing to share info as opposed to learning and keeping it to yourselves.

Kudos!

Mike

[kabacj]

SWEET!!! good find on the shifter stop. Boy thats some shiny gears you got there. See you at Limerock.

Yes I was thankful it was an easy fix. I'm looking forward to Limerock.

the ease with which a Mendeola gearbox can be worked on in an emergency is phenominal!

Glad it was a simple fix for you. I think I called it after seeing your video of how the shifting was acting. That's because we have had the exact same issue

Yep thanks for the help crash. The transaxle is so easy to take apart I'm going to get a few more gear sets so I can have the right gears for all the tracks I run.

Race testing absolutely has it's way of defining what the common issues are likely to be. It's also great that you're both willing to share info as opposed to learning and keeping it to yourselves.

Kudos!

Mike

Yep Mike. It also helps that we don't race against each other .

Seriously since there are so few GTMs that are race legal and or track prepped there is no other body of knowledge then what we share here. As with all Motorsport what is learned on the track makes the street car better. There are still things that must be learned by trial and error. Everybody wins when we learn things. Winning is what we are all about.

[kabacj]

A tip regarding the knock sensors and kooks headers.

I have been running a bit harder lately as well as closed in the under side of the motor with an aluminum panel.

This makes it a bit more toasty under there especially after I come in to the pits after a race.

Last race at VIR I scorched my wiring harness even though it was shielded inside foil covered Fiberglas wrap.


I lengthened my wiring harness and brought the wires farther inboard.

I also noticed that my knock sensor connections were starting to melt.




I relocated them at a slightly different angle and made a shield from foil wrapped fiberglass to prevent further damage.



It's surprising how much heat radiates from the headers. It's probably good practice to anticipate that anything near the headers will be damaged by heat and shield accordingly.

John

[The Stig]

I think you've just helped me to make a decision that I've been struggling with. I have the Kooks headers, and I had the complete system ceramic coated, but lately I've been wondering whether or not I should pull them and wrap them in header wrap in order to block a little more of the heat.

I think if I can figure out an easy way to take them out to do the job, I will put that on my list of things to do when I can get to it.

Mike

[kabacj]

I think you've just helped me to make a decision that I've been struggling with. I have the Kooks headers, and I had the complete system ceramic coated, but lately I've been wondering whether or not I should pull them and wrap them in header wrap in order to block a little more of the heat.

I think if I can figure out an easy way to take them out to do the job, I will put that on my list of things to do when I can get to it.

Mike

Mike.

Since you already have ceramic coated headers (the best solution for heat control) I would just keep a close eye on the vulnerable parts. Some people say wrapping the exhaust can limit its lifespan.

A quickly constructed heat shield will keep all of your plastic parts safe too. Much quicker and easier.

Just a thought.

John

[kabacj]

I got my part from Mendiola last night. After a long day of work I finally got out into the garage at 9.00pm. Luckily the swap was quick.

All of the gears in a sequential transmission are stacked in order from first to fifth on the output shaft. First is closest to the motor and fifth is the most rearward.

Here is the input and and output stack on the ground.



I pulled the upper gear stack till I got to the face plate for third gear and saw the obvious problem.




You can see how both sides of the "teeth" on the face plate are rounded. The side of the tooth that engages the downshift is the most badly rounded.

You can see here in profile the rounded edges. With this condition there was barely any under cut to grab the gear and ramp it into engagement.



This is what it should look like.







On the positive side the transaxle is a breeze to work on as it's clearly been designed to be maintained just like the GP bikes I used to work on. ( it helps a lot when the engineer who designs the transaxle is also the guy who maintains it!)

The other parts of the transmission and gears look brand new.

Going forward I'll just treat these parts as wear parts like brake pads. I'm sure that keeping the shift leaver stops from backing out will greatly increase the lifespan of the faceplate and dog ring. ( the dog ring is the mirror image part held in the shift fork.

Tonight I can start the car up and run it though the gears to make sure all is well. Then I can pack up the trailer. Wow I'll be ready a day early. That's a record.

[fastthings]

Never ends, does it. The most of it seems to be pretty reliable, I hope mine is.
The two fans I put in my engine bay really do well creating a flow of air, I can only imagine how nice it will be pulling in and turn on the fans for about 5 min and all is cool.
You should consider the same.
Looking forward to see some of your videos, have fun man!

[crash]

Just wondering...do you use the clutch when shifting? If you look at our latest video from Utah I am shifting our Mendeola like it is going out of style and only had one or two hiccups, which were clearly my fault. The shifts are VERY quick and I am using the clutch every time. I really see no reason to shift without the clutch and plenty of good reasons to shift with the clutch. One of the biggest is that it seems to be WAY easier on the dogs. I realize this current issue was caused by the adjustment problem, but just thought I would make the suggestion if you are not already using the clutch every time. I know I rarely, if ever, used the clutch on my motorcycle/quad after starting from a stop, but these gear boxes seem to like the clutch use and I am all for doing whatever is possible to keep the wear issues down to a minimum.

[kabacj]

Never ends, does it. The most of it seems to be pretty reliable, I hope mine is.
The two fans I put in my engine bay really do well creating a flow of air, I can only imagine how nice it will be pulling in and turn on the fans for about 5 min and all is cool.
You should consider the same.
Looking forward to see some of your videos, have fun man!

Good idea Gene. Adding more cooling is on my list, but currently I'm finding where the problems are by trial and error. It's going to be hotter when I add a rear window. I'll probably need fans then.

Just wondering...do you use the clutch when shifting? If you look at our latest video from Utah I am shifting our Mendeola like it is going out of style and only had one or two hiccups, which were clearly my fault. The shifts are VERY quick and I am using the clutch every time. I really see no reason to shift without the clutch and plenty of good reasons to shift with the clutch. One of the biggest is that it seems to be WAY easier on the dogs.

I'm with you crash. I also clutch on shifts to make life easier on the dogs. I agree there I no real time penalty for the clutch and I like to take it easy on the equipment. I find as I'm sure you do running endurance being gentle with the equipment keeps you on the track longer. You need to first finish to finish first as they say.

I watched your video and I think I'm going to get a set of shorter gears. I shift less as I'm basically only ever in 3rd and 4th with 5th gear starting at 150 . I think a little more revs will help in tight traffic.

From your video. I like how in Arizona you trail dust for half a lap after doing a little off roading. With the dust trail its possible to see how well the wing is working.

Thanks for the tip.

John

[crash]

Gearing is, as you know, a very important element in getting everything you can from the car. If you watch the Utah East Loop race I am shifting like crazy and, after review of the video, I probably should have shifted about 3-4 more times per lap. You can see the Vette and BMW pull away from me in the short straights where the GTMs legs don't get a chance to stretch. The issue was that we were down on power because of the elevation and our gearing was not correct for the track. This resulted in me having to try and get all the power out of the car by keeping the engine high in the power band. Because the gearing was a bit in between what it should have been for this track, I was having to shift quite a lot because I didn't want to drop the revs, but then would find myself bumping up against the rev limiter. A set of drop gears would have made a huge difference in being able to set the gearbox up quickly for this particular track, but alas, I don't think Mendeola is ever going to put this feature into their transaxles.

We go back next month to Utah and will be running the big outer loop course so top speeds should be significant and we will also be putting the larger engine in and removing weight, so things should be better for that race, even without any gearbox adjustments.

[kabacj]

Gearing is, as you know, a very important element in getting everything you can from the car. Because the gearing was a bit in between what it should have been for this track, I was having to shift quite a lot because I didn't want to drop the revs, but then would find myself bumping up against the rev limiter. A set of drop gears would have made a huge difference in being able to set the gearbox up quickly for this particular track, but alas, I don't think Mendeola is ever going to put this feature into their transaxles.

Yep I agree drop gears are the easiest way to switch the setup the car. Next is having a box of ratios to swap in. Although I formerly was very happy just running in two tall gears all the time that is not the ideal way to go fast in traffic. Especially in a race , like you had and the 25, with small displacement cars mixed with the big bore cars.

I was happy running a setup where I shifted less as long as I could carry corner speed to compensate. When you get balked going into a corner by a slower car then having the right gear is more important.

I'm going to discuss my options with Ian at mendiola. Maybe we can come up with a short 3-4-5 combo that would be better. Or... I can just add power😃

The other thing about following a pack in traffic is visibility. I noticed you had to deal with that. All I ever see are trunk lids. It's like racing through a pack of SUVs. Sure would be nice to see through the cars ahead. NAH ! Being low is cool.

[crash]

We worked with Ian quite a bit to get the gearbox right for the two tracks we primarily run. One is tighter, and one is more wide open, so we geared it so that we run gear 2-3-4 on the tighter track, and 3-4-5 on the faster track. It works very well for those two tracks, and anywhere else we run we try and "make do" so that we are not constantly working on the gear box. It's a compromise, but usually our relatively high HP to weight makes up for any gearing issues. Unfortunately the USTCC, the series we have only begun to run this year, has a HP to weight rule that makes us run less HP and more weight. We were almost 3200 LBS in Utah with just over 300 HP at the rear wheels.

Hence, shifting like crazy to get all the power out of the engine I could.

Visibility IS an issue, but really much more of a problem when trying to see to the rear. You will notice our "different" rear view mirrors mounted on the front fenders. They work pretty well, but the spotters work even better. If you are going to seriously race this car I would highly recommend getting a buddy to spot for you. Especially if there are faster cars than you on the track.

[kabacj]

That's a good point Crash. Speaking of Mirrors. I had planned to change my mirrors to get a wider field of view but now that I have grown accustomed to using the rear camera I think I am less motivated.

I use this screen and camera. Both very cheap so I have a spare set.



http://www.amazon.com/gp/aw/d/B007SL...Y3VPY5R2P0HXC#






http://www.amazon.com/gp/aw/d/B005Q6...0WL&ref=plSrch


Both have been soaked in water and vibrated harshly for over 80 hours on the track and are fine.

Not sure how it would work for night racing as I have not done that yet, but it's worth a try.

It's just as good as a multi panel racing rear view mirror in a conventional car. You only need to get used to the aspect ratio and then it's perfect.

Of course spotters are better but more information usually helps.

[crash]

We actually explored the rear view camera stuff pretty extensively. We went through a regular rear view camera such as you have there, and also tried a FLIR camera. The problem for us was that we are so busy racing with 60 other cars on the track that we literally have no time to look down at a screen or even the gages. We use the gages to identify what has gone wrong as opposed to heading off problems because we are quite busy passing 8-12 cars a lap. Yes we lap some cars every three laps! The option of putting the display up where the bump in the hood is was discussed, but it never happened. The mirrors seem to work fine combined with a spotter or two.

[flickery8]

The mirrors seem to work fine combined with a spotter or two.

Crash has "special" mirrors that I wish I had. They stick up several inches. With my widend rear fenders my mirrors give me a good view of my fender. I have bought some extra mirrors to try to attach to the A pillar, but haven't figured anything out yet.

I have a rear view camera, but mine is not bright enough for my liking. Has that been an issue John?

[kabacj]

O

I have a rear view camera, but mine is not bright enough for my liking. Has that been an issue John?

Hey Fickery

The screen I have is pretty good. If it's a very sunny day I'll just put a shade over it so the sun does not shine on the face of the screen.

Glare into the camera is the only issue I have had. This happens late in the day when the sun is shining into the lens at a low angle. I have a better camera that I have yet to install. Maybe that one will auto white balance a bit better. At 5x the cost ($100) I hope it does.

I had the RCA jacks pull out once, but now I duct tape them together and they have been good.

[kabacj]

Fun weekend at Lime Rock Park

Saturday was a picture perfect July day. 80 degrees sunny with a light breeze.

Limerock park is set in some of the most picturesque real estate in Connecticut. Every time I drive up I think to myself "I can't believe there is a race track in the middle of this "

That's most likely why there are only a few unmuffled days where we can take out loud cars out on the track.

This is only my second time at Limerock. I'm starting to like it a lot. On the down side Limrock barriers total a few cars each weekend, but if you can keep all four wheels on the pavement it's a blast.

Me having fun.




As nice as Friday was. Saturday weather was not as good for my setup.

I had a nice new set of front R7s that I needed to scuff prior to the race.


Practice was drizzling. I went out on scuffed Hoosier A6 slicks but cut the session short as it was a little too slippery.

Qualifying was full wet. Guys with rains were happy. I only had a set of well worn 888s. Last time I ran them in the rain the rears would hydroplane over the smallest standing water.

I'd rather start from the back then loop my car into a wall so I stayed in the pits.
Turned out the race was just as wet. Unprepared for the conditions (the forecast was for sunny skies!) I figured discretion was the better part of valor.


My fellow factory five drivers went out and qualified well and raced very well. Pat and John had a great weekend bringing home plenty of hardware.



Here Pat leads and gets the over all and class win.





That's two years in a row where Pat won the Fourth of July race in the wet. His win was great to watch( normally I can't watch our race) and a great conclusion to the weekend.

[crash]

I think you made the right decision. These cars are a handful in the rain.

[kabacj]

I think you made the right decision. These cars are a handful in the rain.

I'm interested to try a set of full rains. My experience racing motorcycles using rain tires was night and day. I could put my knee down on the pavement in a downpour. With dot R compound treaded tires I would instantly crash if I tried that.


I actually like driving the GTM in the rain. (As long as I have some tire tread). Wet track takes the traction limit from super high to normal levels which feel safer to explore.... Even if they are just as difficult

I just don't like testing traction with a wall a few feet off the track. I gotta hand it to the guys who raced on SAT.

Next year I'm bringing rain tires so they better watch out! Ha ha

[crash]

It really depends on the rain tires. We(I) tested three different brands of rain tires last year at the 25 and there is a HUGE difference. Not saying that driving in the rain fast is not doable in a GTM, but certainly a front weight biased car is much easier to deal with when the rear is trying to put power down. Just like in the dry, the mid engine GTM has a much smaller window of error as compared to the front engine cars. I have had very little issues driving for hours at speed in the rain in the FFR PDG GTM, but have looped it twice during wet track events. Usually the biggest issue is when it just starts and half the track is wet and half the track is dry. Very difficult. Must watch for water on the windshield. When in doubt, be safe. Rain, grass, and hard walls are not safe. You made the right choice.

[kabacj]

It really depends on the rain tires. We(I) tested three different brands of rain tires last year at the 25 and there is a HUGE difference. .

Which rain tires do you like? I was thinking of going with Hoosier H20 but that choice would only be because they are the ones I see most guys use.

[Stage7]

You are the man Kabacj! You've been busy getting things done. Impressive. We should lunch again soon.

[kabacj]

You are the man Kabacj! You've been busy getting things done. Impressive. We should lunch again soon.

HI Stage. Thanks! I'll PM you. We need to catch up.


Yesterday was a mile stone. I got my New York State VIN.

As usual there was paperwork and process but the final hurdle was physical.

I needed to drive the GTM into their shop for inspection. Easy enough...except


I took the GTM on the trailer to the inspection location. The shop has a small parking far too small for my pickup and 30 foot trailer. lI park on the street. Uh oh. The ramp into the inspection station has such a drastic hump I'm sure normal sports cars scrape. The GTM would scrape then high center.

I explain my situation to the DMV who were shockingly nice. They said just back the trailer in and offload. Ok that means I block 15 cars into the lot. Hmm this is going to be good.

Ok just unload the GTM now. Oh great. The parking lot has a drastic pitch and now one side of the trailer door is 12 inches in the air. Luckily I have lots of wood and two piece race ramps.

I rolled the GTM out on the ramps and trailer door enough so the inspectors could check it out. But no way I was unloading it. Whew. I got my VIN.

I added this rear marker light as its required in New York. I need to find a nicer one




One more piece of paperwork and I'm ready for safety inspection.

[mikespms]

Congratulations! A lot of heads are going to turn when drive down the street on a street legal race car,awesome!

I took my car to the dmv inspection on a trailer and the inspector was very nice,there was a crowd around the car asking questions and taking pictures and he was annoyed with the people and told me not to unload the car he just went over the requirements and asked me if I complied and gave me the vin decal for me to put on the car while he watched.

[Fraser D]

Congratulations John!

[kabacj]

Thanks Mike and Dave. On to a part of the build both of you are familiar with. Fiberglass work!

Before the weather turns cold I need to get the GTM painted.

Much easier to do when I can bake the car in the summer sun and spray in a temporary tent outside. Not to mention making dust outside is much nicer then making a fog of dust in the garage.

Step one is to expand the body to cover the larger front tires.

My first set of tires were 245s. Now I am running 295s. They stick out of the body quite a bit. I also needed to cut the wheel wells for clearance.



No problem. I just need to flare out the wheel wells a bit. I've read about this technique in books, but never tried it. Oh well here goes.



I just used insulation foam to build up the shape. Actually was pretty easy. It just took a few hours.



I matched both sides and put down a few layers of epoxy and fiberglass cloth and I had this. Still lots of trimming and shaping to be done as both sides are a bit over sized but the basic shape is getting there.



Now all I need to do is blend the hood into the body then I can perfect all of the lines. I'm working on that now.

John

[kabacj]

Lots of dust at my house.

Spent another few days tweaking and re tweaking the front fender flares to cover the bigger 295 tires.

I have a curse that I can see very tiny variations in symmetry. And yes It's a race car, but I never can stop at that's good enough for the traditional 50 feet and 50 mph.

I'd rather wreck a perfect car then have a car I don't mind wrecking

The shaping part is fun. The fiberglass splinters are a little annoying.

I used epoxy and glass cloth to rebuild the fenders. The positive of epoxy is it's a little stronger then polyester. It sticks way better to the current body then polyester resin and I can use cheap foam to build up the parts. (Polyester resin melts the pink foam you get at Home Depot) so far the hood is lighter then when I started.

A gallon of epoxy resin and hardener is over 100 bucks. But parts are strong and light. And more importantly I can get foam at Home Depot very cheaply. I think epoxy is the way to go.

Yeah I am tempted to just send it to somebody, but as everyone knows 1% of the body/ paint guys can deliver a finished product as promised on time... And none of them (unless it's your personal friend ) are going to put love into the car.


On the good side the remainder of the bodywork should be easier. Just a few little items to address

As usual I have a deadline. Oct 25.

I love deadlines.

John

[Fraser D]

I am looking forward to seeing your progress.

[carbon fiber]

I've had some bad results with epoxy on polyester and vinyl ester in the past. (GTM is vinyl ester) I know some will disagree, as I've had this conversation on both forums now. I use the same materials the original part is made of. Epoxy does have a better bond than vinyl ester in general, but the vinyl ester seems to melt together with itself better than epoxy bonds to it. One thing to consider is making a multi piece mold of your finished front end and make a new one in one piece. I know a lot more work, but I'd do that anyway, so that if your front end is damaged you'll be able to replace it easily verses having to repair it or redo all the work you've done modifying it. (You could have a spare ready at home if you need it.) I'm making molds for my revised bodywork. (Admittedly more time/mods to worry about than what you've got there) Just something to think about.

[kabacj]

I am looking forward to seeing your progress.

Yes I know Dave. I need to post pictures. I'll get on that.

I've had some bad results with epoxy on polyester and vinyl ester in the past. (GTM is vinyl ester) I know some will disagree, as I've had this conversation on both forums now. I use the same materials the original part is made of. Epoxy does have a better bond than vinyl ester in general, but the vinyl ester seems to melt together with itself better than epoxy bonds to it. One thing to consider is making a multi piece mold of your finished front end and make a new one in one piece. I know a lot more work, but I'd do that anyway, so that if your front end is damaged you'll be able to replace it easily verses having to repair it or redo all the work you've done modifying it. (You could have a spare ready at home if you need it.) I'm making molds for my revised bodywork. (Admittedly more time/mods to worry about than what you've got there) Just something to think about.

Yeah. This is V 1.0. Of the hood. Just the fenders and some minor tweeks

Since the paint only looks good for a season I'll be painting it again this time next year or sooner. I'll add round two of changes after I can test the aero changes of V 1.0

I should make a mold. That's yet another thing I have never done before. At least I'll know who to go to if I have questions.

[carbon fiber]

If you need any info just PM me. Your suspension info is helping us all.

[longislandwrx]

how did the paint job go? will I see it cruising around East Northport before it cools off?