When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Scott,
I'm curious on your transmission woes...shouldn't a Jerico by more than stout enough to deal with what you are throwing at it? I mean they are supposed to be rated up to 750hp in a 3200lbs car. For the cost involved I would expect it to be virtually maintenance free. Can you tell what I'm missing?
It a fair question and one I have asked over the years. What I have observed is that racing specific parts have increased maintenance intervals and costs when compared to OE equivalents. In some cases it is because the race part is built to be lighter and absorb less HP at the cost of longevity. In other instances, the race part allows you to use it in a way that is ultimately more detrimental to a long service life.
For example with a close ratio gear box, I am shifting 14+ times a lap. With a stock RX7 box or even an RX7 box with a Miata gear set, I would be shifting less (I never used 5th gear) because the wide ratio spread. More shifting equates to more use and more use equates to more wear. More wear means more maintenance.
But there is an upside. With a Jerico (or a transmission like it) you get a transmission that an engine like ours cannot break. So that means no stripped gears, split tail shaft housing or sheared input/tail shafts that put you out of a race. You are also getting the gear ratios of your choice, reduced friction (everything is in roller bearings), reduced parasitic drag (straight cut gears) and faster shifting.
This year I am trying to solve a 4th gear vibration. I am replacing all of the bearings that are engaged when the transmission is in 4th. So I am replacing the pilot bearing, front case bearing, rear case bearing, input shaft to main shaft needle bearings and the tail shaft roller bearing. Of course, all of these bearings that are in place now "feel" fine but I can't accept that. Nothing "broke" but something is wearing out. Also had my inventory of Coleman drive shafts checked for balance at a local shop that has a good reputation for these kinds of things.
It a fair question and one I have asked over the years. What I have observed is that racing specific parts have increased maintenance intervals and costs when compared to OE equivalents. In some cases it is because the race part is built to be lighter and absorb less HP at the cost of longevity. In other instances, the race part allows you to use it in a way that is ultimately more detrimental to a long service life.
For example with a close ratio gear box, I am shifting 14+ times a lap. With a stock RX7 box or even an RX7 box with a Miata gear set, I would be shifting less (I never used 5th gear) because the wide ratio spread. More shifting equates to more use and more use equates to more wear. More wear means more maintenance.
But there is an upside. With a Jerico (or a transmission like it) you get a transmission that an engine like ours cannot break. So that means no stripped gears, split tail shaft housing or sheared input/tail shafts that put you out of a race. You are also getting the gear ratios of your choice, reduced friction (everything is in roller bearings), reduced parasitic drag (straight cut gears) and faster shifting.
This year I am trying to solve a 4th gear vibration. I am replacing all of the bearings that are engaged when the transmission is in 4th. So I am replacing the pilot bearing, front case bearing, rear case bearing, input shaft to main shaft needle bearings and the tail shaft roller bearing. Of course, all of these bearings that are in place now "feel" fine but I can't accept that. Nothing "broke" but something is wearing out. Also had my inventory of Coleman drive shafts checked for balance at a local shop that has a good reputation for these kinds of things.
As a bonus....my Jerico order ships tomorrow!!
That all makes good sense. I certainly get the benefit on choosing ratios etc... My thought process was in a relative low HP application wear and tear would be minimal but yea...restance to breakage doesn't equal low wear or maintenance. Thankfully for us, a mostly stock FB box has been working for us for the last few years. The only upgrade I think it has is FC input shaft bearings...something about dual rollers vs single. We did have dome 3-4 syncro wear so that and bearings are currently getting replaced.
In my defense, I swapped the motor, carb, tranny, driveshaft, hood, pads, front brake rotors, and basically rebuilt my nose last fall before the Runoffs. So, technically, I only have one event on the car since I overhauled everything in the fall. I will changing fluids, etc. before the event. I do have stiffer springs all the way around that I will change over the race weekend. Trying to finish my new torsion style sway bar by then but bending the arms have presented itself to be a problem(3/4" 6061 Alum.).
In my defense, I swapped the motor, carb, tranny, driveshaft, hood, pads, front brake rotors, and basically rebuilt my nose last fall before the Runoffs. So, technically, I only have one event on the car since I overhauled everything in the fall. I will changing fluids, etc. before the event. I do have stiffer springs all the way around that I will change over the race weekend. Trying to finish my new torsion style sway bar by then but bending the arms have presented itself to be a problem(3/4" 6061 Alum.).
And maybe I can also squeeze in a wash.
This thread is taking on elements of a trip to the confessional!
As I recall, David Long and Charlie Clark had the same issue when they built their sway bars. I will ask Charlie about his today. But I think they had to use a hydraulic press to get the shape right. What spring rates did you go too?
I had big plans after the Runoffs but a week after I got home some thieves tried to drive a truck through the shop's garage door. For the next several months we focused on building a 18x10 foot rolling gate with a separate 4x10 foot man door to control access to our area. Also had to reconstruct the hasps on another door that is in front of a secondary storage building. Finally I added a bunch of anti-cut defenses to the man door on the main shop. So lots of fab work and welding on things that aren't race cars.
Nothing was stolen but getting a replacement garage door right now was a PITA. We did have a door that covered the opening but it was drafty. Fortunately we got a proper garage door before it got super cold. By the way, the thieves around here are using cordless sawzalls to cut lock hasps. They aren't attacking the locks but rather how the lock is attached to what it is securing. Anyone with a bar lock style door lock on their trailer would be wise to get a lock that covers the hasp completely. Adding material to the bar lock to make it hard to cut through would also be a good idea.
Any way, I am back to working on the car. Will have the transmission back together next weekend and should make a decent start on the engine today. Assuming all things go smoothly, I will be everything back in the car later this month.
I am glad they did not get thru, that would SUCK! Aren't you subterranean?
I had to look up the springs, have had them for months. 650#front and 350# rears. That would be up from 550/275. Darren is running even higher rates. I can see from photos that my front is jacking up pretty high on hard cornering. Thinking also of fabbing a strut cross member but that would require to completely redo my custom airbox.
Glad to hear you are back at it! Need to get ready for the season. I am actually listening to the COTA HST in the background to fire me up. I will be working on a racecar this weekend, just not mine... My son Connor's car. You may recognize the rims.
Conner's car is nice! You're keeping my old Panasports clean! Love it!
Wow, those are some stiff springs but they are inline with what the famous racing driver had on his EP RX7. I am planning on going to 300lb springs in the rear because the car really doesn't rotate very well. I have the rear sway bar to try as well.
So for the sway bar, Charlie and Roy have them on their cars and they recommend making a pattern of the shape you need and then find a Circle Track/Sprint Car shop to get them bent. Sprint car guys work with these all the time. They will heat them up and bend them into the shape you need. If you attempt to bend them cold they will fracture.
Nope we are above ground now. We were booted from the cave in 2020 when the owners decided they wanted only food storage tenants. I was fine with the move. That cave was dusty, stinky and the floors in our area were not level. Working out of a cave can be pretty cool if a reasonable space can be found. This time around we couldn't find one.
Not for the first half of the year, I’m running five west coast majors in EP. I see that the NASA champs are back at Laguna. I might drag out my old PTE car for that. Not sure where it fits in ST though.
Not for the first half of the year, I’m running five west coast majors in EP. I see that the NASA champs are back at Laguna. I might drag out my old PTE car for that. Not sure where it fits in ST though.
Apparently a bunch of people built cars in the last two years, so ST5 is looking interesting. once we had to measure our own tires i kind of refused to read the rules, its just stupid, so i don't know where anything fits anymore
Sorry to drag the thread back to louvers, but misrepresented data drives me nuts. 302blown's post is pretty misleading on the performance of their louvers. I agree that their wind tunnel data demonstrates that their louvers result in more air through the radiator than other designs.
Anyway, using the data they present for "differential pressure (dP) across the radiator", the increase (relative to no-louvers) in airflow through the radiator that can go through radiator plays out like this:
common raised louver - 1.4%
Race Louver RS - 1.7%
Race Louver RT - 2.5%
Race Louver RX - 4%
Comparing the RX to common-raised louvers shows that the RX allows 2.6% more total airflow through the radiator than common raised.
In other words, not double the cooling from the most important/interesting perspective, which to me would be relative to no-louvers. In their defense, I am sure they meant (but were hoping us consumers would misunderstand) that the RX louver provided twice as much additional airflow than a common raised louver. The number is small and might be meaningless when trying to apply to cars with different aero configurations.
I am sure their product is fine and I commend them for actually doing wind tunnel testing (as if anyone realistically cares what I think). I am not bad-mouthing anyone here, just trying to put the data in perspective.
Downforce is way out of my area of understanding, but I suspect the improvement numbers are being reported in a similar way.
I'm looking at running my car in GLTC when GridLife comes to Heartland Motorsports Park in October. Any of you guys run one of these events?
Since I will have to buy some 200 UTQG tires, what do recommend? Based on weight (which is heavier than my SCCA weights) I will be limited to a 225.
By the way, based on my calculations my GTLC minimum weight would be 2575lbs. if I don't run any aero devices.
The fastest 200TW out there right now is the Yokohama A052. They are available in 225 and have a reputation of being large for their rating, so if you have any 15X9 wheels they should be perfect but Should also work well on a 15X8. The bad news is that they are a little pricy, these A052’s are so soft that we can’t even get them to last a 7-hour race.
Other options would be the BFG Rival S, or Falken RT660. The Falken is pretty much a clone of the Bridgestone RE71 which is discontinued but was only available in 205-15 while the RT660 is available in 225, and 245, and very affordable. The Falken’s wear fast but if you are not endurance racing it shouldn’t be a problem
The Nankang CR1 is very similar in design to the A052 but a little less money. They are available in larger sizes with a 275/35-15 on the horizon.
Another possible tire you may want to look at is the Cooper RS3-R, it is more of a true endurance race tire, which nowadays means you can get a 7-hour race out of a set. They are only available in 205-15 for now, the possible advantage to you is that these are made by the old Avon race tire division in the UK. The construction is like a real racing slick with very stiff sidewalls, this could make them work better with the suspension setup you have on your car.
Of course, between now and October the whole market could change with some hot new entry to the market. Also be aware that some of these tires are notoriously difficult to find later in the year, they send over so many containers every spring and when those are gone, we are left waiting until the next year.
MHR650, Conekiller13.....So since the GLTC races are 20 minutes long I should look at the Autox side of the 200UTQG spectrum? Do you think weight should be a consideration? Because I will starting the race at 2650lbs or so.
MHR650, Conekiller13.....So since the GLTC races are 20 minutes long I should look at the Autox side of the 200UTQG spectrum? Do you think weight should be a consideration? Because I will starting the race at 2650lbs or so.
Yes, I definitely would. The endurance tires like the Hankook RS4 etc won't give you the ultimate grip the more performance oriented 200 tw tires will. The heavy wear on the Yokes is certainly exacerbated by heavy cars but camber or camber curve really seem to be thieir limiting factor.
Yes, with 20-minute sessions no 200TW tire is going to be too soft. Some guys at work run an E46 which with fuel and driver must be pushing 3000lbs, they were able to get 5-6 hours from a set of 225 A052’s at Barber which is pretty tough on tires.
As always with these cars the key to tire life is front to rear rotation.
I hadn’t heard of the GLTC before so I checked it out, turns out they are coming to my favorite track in March, I just may go check them out. Looking at the rules looks like I would have the same problem you have of needing to add a lot of weight to fit their rules. We are unique racing in a series which doesn’t have minimum weights so it is important to work as hard as possible to get the cars light, my goal is to get down well into the 1900’s, but it will be a lot of work.
I have been using Toyo Proxes R1R tires the past two seasons. If you are looking for a tire that has grip right out of grid then you may want to try it. But it only has about 3-5 laps of grip before they lose lap time. They are also the best tire I have used in the rain that isn’t a dedicated rain tire. I am using 225/45-15 tires on a 15x7 wheel.
I have been using Toyo Proxes R1R tires the past two seasons. If you are looking for a tire that has grip right out of grid then you may want to try it. But it only has about 3-5 laps of grip before they lose lap time. They are also the best tire I have used in the rain that isn’t a dedicated rain tire. I am using 225/45-15 tires on a 15x7 wheel.
I agree the R1R makes a good rain tire, you see teams show up with a set sometimes when rain is in the forecast. It is a possibility that they fit into the 20-minute session use case better than other tires which are either designed for endurance racing, Hankook RS4 and Continental extreme contact force, or autocross which is pretty much every other recent tire in the category.
But I seriously doubt it, the R1R is a very old design, which has been around for more than a decade. If they could keep up with the Yokohama’s people would be winning in autocross with them, and they are not. They did 10 years ago when they first came out.
The multiple 20-minute session format sounds a lot like time attack, and in that format, in 2022 the Yokohama A052 or Falken RT660 seems to be the tire to have.
I had a set of R1Rs for rain tires and ran them once in damp/wet conditions. They worked and I stayed on track. I picked up a set of used SM Hooiser H20s and well...even used they are kick ***. I believe the magic R1R was the 195/50x15. Autocrossers swore by them on H Street Minis.
Reading that article and the linked comparison tests, the concern I have with the "Super 200s" is that the fast ones (Yoks, Falkens, etc) peak on lap one or two and then fall off from there. My concern is how well would they recover from several turns that are over-driven. I know that Hoosier R7s and the Goodyear RS tires are "softer" than any of the tires in the buyers guide but they also handle the heat generated in racing conditions.
This is kind of a unique situation - sprint racing on 200 UTQG tires. The SCCA just mandated these kinds of tires for Improved Touring but that doesn't take effect until later in the year. Also, IT cars generally lighter than what is spec'd in gridlife.
02-03-22, 03:24 PM
