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BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
10/6/20 11:59 a.m.

In reply to Pete. (l33t FS) :

It's actually got coilovers all around. Unfortunately I think they're only height adjustable. I suspect softening the rebound a bit would help, but that doesn't look like a possibility. 

TurnerX19
TurnerX19 SuperDork
10/6/20 7:06 p.m.

This chassis has a lot of (relative) unsprung weight in the rear. I built a DSK for a customer with this rear (and a ported 13B) which had a distinct rear hop in bumpy conditions. New Konis with the springs provided in the "kit". 1217 pounds with 17 gallons of fuel onboard. Hop got very worse as fuel departed.

Oh how I hate,

Unsprung weight.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
10/8/20 5:26 p.m.

Project introduction on the 'tubez:

 

 

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
10/8/20 5:27 p.m.

In reply to TurnerX19 :

Interesting. Again, I didn't expect this to handle and feel like a Miata, so I think it's a case of 'living with it' for now.

TurnerX19
TurnerX19 SuperDork
10/8/20 7:27 p.m.

The hop was reasonably predictable and fun when you got used to it! Easy on track, less comfortable for brisk road use in unfamiliar territory....

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
11/8/20 3:27 p.m.

Well, given the unreasonable weather here - around 70, nice and sunny - I decided to take the Rollerskate out for another run. Probably the last one of the season. It also gave me a chance to top up the tank and drop some Idemitsu premix in there.

I got a big grin out of running it around my "test loop", which is a mix of mostly backroads with a bit of dual carriageway. It seemed to appreciate the longer run and ended up running a lot better at the end of the trip, especially after I did the usual "drive it like your name is Luigi and it owes you money". I also suspect that running it for longer helped out clear the carbs out a bit better, and as a result it felt at least like the fuel starvation wasn't that bad towards the end of the run.

Noted a couple more issues I need to look into:

  • Got some vibration through the steering wheel at about 55-60 mph. I suspect this may be related more to the brakes or wheel bearing than to the (new) tires as I'm also getting some pulsing through the brakes.
  • The brakes are a bit odd - they get "softer" with more travel at higher speeds, but there is no brake booster. The brake system is on the list of things that need work anyway, so I'm hoping I'll be able to figure that part.
  • When you bottom out the rear suspension you also end up dragging the exhaust on the pavement. Oops.
  • Not having a working speedo or odometer is really annoying, especially if you also have a non-working fuel gauge. No, I didn't have to push it home.
Dusterbd13-michael (Forum Supporter)
Dusterbd13-michael (Forum Supporter) MegaDork
11/8/20 4:00 p.m.

Could the brake spongy and vibrating be due to a warped rotor or bad wheel bearing causing piston knockback?

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
11/9/20 6:56 p.m.

In reply to Dusterbd13-michael (Forum Supporter) :

That's entirely possible. Thanks to the awesome Maxton Rollerskate group over on FB, I now know what brake lines I need to replace the original ones (front are Mustang II, rear is RX7), so I feel another RockAuto order coming on that should hopefully get me to the point of a brake overhaul. Well, once I found some slightly better brake pad compounds, but that's just Mustang II stuff anyway so I should be able to find some Porterfields or something.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
11/15/20 10:31 a.m.

Someone's been on eBay...

Should contain just about any information about the drivetrain that I need.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
12/2/20 6:54 a.m.

Not much progress on any of my vehicles, however I still got to take the Rollerskate out for a spin a few weeks ago thanks to some unseasonably warm weather, so I decided to try out the new action cam and get some local backroads footage:

 

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) MegaDork
12/2/20 7:02 p.m.

In reply to BoxheadTim (Forum Supporter) :

That looked fun! Dammit, I really need to build/buy a Seven-esque clone. 

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
12/3/20 2:28 p.m.

In reply to Pete Gossett (Forum Supporter) :

Thanks! It is fun, at least on backroads on days when you don't have to wear several layers of sweatshirts .

Scotty Con Queso
Scotty Con Queso SuperDork
12/3/20 3:06 p.m.

Enjoyed the YouTube vids. 

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
12/4/20 8:53 a.m.

In reply to Scotty Con Queso :

Thank you.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
1/21/21 7:54 p.m.

Not that much news on the car. THe original plan was that I would use this car for track and the occasional Auto-X, but it looks like that's a no go for various reasons (like the fact that it sports. four point harness. At least for NASA, I would either have to fit belts that match a specific FIA homologation or retrofit a 5 or 6 point harness. Fitting the latter likely requires taking the body off and modifying the frame (and possibly changing the sear), which I don't want to do. Also, while the roll bar meets the letter of the rules, it's a tad iffy for track use (which I suspected).

Sounds like what I have is an interesting Auto-X car. Which also explains why the only videos of one of these in action are running an Auto-X, which the only exception being the original Motorweek videos that show the car on the track for a test drive somewhere in Colorado.

I think it's time to re-arrange the shop on the weekend and see if I can get a third car into the shop if I put the Maxton and possibly the 911 on dollies. I'm pretty sure that should be possible if I stick to something relatively small.

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) MegaDork
1/21/21 8:41 p.m.

In reply to BoxheadTim (Forum Supporter) :

Another Miata?

Woody (Forum Supportum)
Woody (Forum Supportum) MegaDork
1/21/21 8:42 p.m.

I think that Schroth makes a street legal four point harness. Would that get you on the track?

I tried a set of their Rally Cross harnesses, but I didn't like the distance between the shoulder straps where they met the lap belt, at least in conjunction with the mounting points in my Miata.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
1/22/21 7:59 a.m.
Pete Gossett (Forum Supporter) said:

In reply to BoxheadTim (Forum Supporter) :

Another Miata?

I'm not looking at Miatas, I'm over them, I can't hear you lalalalala...

Oh look, shiny NB.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
1/22/21 8:05 a.m.
Woody (Forum Supportum) said:

I think that Schroth makes a street legal four point harness. Would that get you on the track?

I tried a set of their Rally Cross harnesses, but I didn't like the distance between the shoulder straps where they met the lap belt, at least in conjunction with the mounting points in my Miata.

I'm aware of the Schroth ASM, actually had one in a Miata (oh look, there's that word again) years back. I'm not sure if that does fulfill the FIA homologation requirements that NASA is asking for. I'm also not sure it's a good idea - the ASM basically has some 'give' in it that allows one shoulder (and presumably your head) move forward in case of an accident, kinda like a three point belt does.

I'm not sure that's a hot idea in this car. For starters, I don't think it has a collapsible steering column, although I may be wrong about that.

Taking this car to the track *might* not have been one of my better ideas, the longer I think about it.

adam525i (Forum Supporter)
adam525i (Forum Supporter) HalfDork
1/22/21 9:03 a.m.

Schroth also offers this style of 4-point which is FIA approved as well as approved for use with a Hans device (they like to call it a FHR) unlike the older Rally style belts. It still comes with the very large stigma of a 4-point harness but I'm sure it is also a big improvement over what is in the car. There are a few to choose from and some even specific to Caterhams/Lotus/Westfields.

Someone in your other thread also suggested a formula style 6 point harness, those have the sub straps run under your legs and back to the lap belt pickups. I've heard that HMS Motorsports is really good to talk to on stuff like this and they are a supporters of GRM. I'd reach out to them and see what they think before writing off this car for track.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
1/22/21 1:32 p.m.

In reply to adam525i (Forum Supporter) :

I'll have to check the exact homologation on these belts then. The issue here is that these belts don't only have to be FIA homologated, they have to adhere to a very specific FIA standard. HANS support would be good as I already have a HANS device, but the belts in the car won't work with it as they're too wide.

I'll have to see how the current belts are fitted - hopefully without having to take the car apart further than I want to - to see if the formula style six point belts would be an option. I'm a tad hesitant to make that change though, simply because it's not going to make the car any more streetable than it already isn'.t

BrianC72gt (Forum Supporter)
BrianC72gt (Forum Supporter) New Reader
1/24/21 6:50 p.m.

When you pull that Dellorto apart, get yourself a torch tip cleaning kit for $5 off amazon - hey, now they even call them carb cleaning wires.  They are a set of finely calibrated wires thin enough to pass through the small openings in a carb to clear any crud that might find iis way into the tiny holes in an emulsion tube.  Also don't forget to replace the diaphragm on the acceleration pump.  I would focus on the things that deteriorate or get obstructed first before changing settings.  Fantastic little car, thanks for sharing.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
1/24/21 6:52 p.m.

In reply to BrianC72gt (Forum Supporter) :

I prefer toothpicks, they won't harm any drilled passages.

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
1/24/21 7:16 p.m.

I'm toying with the idea of getting an ultrasonic cleaner. I have a few bike carbs that would benefit from one anyway, so getting one big enough to dunk a Dell'Orto might be a smart move.

Re modifying the carb - I had a chance to talk to the PO recently and he thinks he didn't replace anything but gaskets when he rebuilt the carb a couple of years ago. I expect all the special parts to still be in place, and I don't think it needs anything but a good clean.

The one thing I am planning to change at some point is to see if I can get better mid range by hooking up the vacuum advance. Racing Beat usually didn't do that on the side draft/down draft conversions and that makes for a distinct VTEC-yo experience at 3k rpm. And the engine doesn't even have valves...

BrianC72gt (Forum Supporter)
BrianC72gt (Forum Supporter) New Reader
1/24/21 10:05 p.m.

In reply to BoxheadTim (Forum Supporter) :

I daily'ed an 72 MGB-GT into NYC with a side draft DCOE that also stumbled down low.  Also no vacuum advance - full mechanical. It took some playing around with weights and springs to get a decent rip from idle.  I think Mallory also makes an adjustable full mechanical dizzy.

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