12:05 Garage- ’70 Duster build
- Thread starter racerjoe
- Start date
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DionR
Well-Known Member
I was a TurboDodge guy for awhile, lusted after a GLH or GLHS but had a T2 GTC instead. Still wander back into the forum once in awhile.
Red Stripe
Well-Known Member
Nice work! Car looks amazing as always.
DionR
Well-Known Member
I wouldn't feel bad, I don't think I saw a singe picture of the class winner. I even went looking for a picture of the Late Model class winner and only found one.
The widebody Volare looked cool. But I have a bit of a soft spot for F-Bodies.
racerjoe
Well-Known Member
Yes the Volare is a neat car. I think it's a 4 speed too, which raises the cool factor in my book. The only thing missing is a mullet flying out the T-tops and some big mirror sun glasses!
DionR
Well-Known Member
71340
Well-Known Member
I saw your car there and it looked real flashy me! I took a photo for myself.
racerjoe
Well-Known Member
This week is Cruisin the Coast in coastal MS. I've lived an hour away from it my whole life and never attended until last year with a friend. There was over 10,000 cars pre-registered and lots of people don't pre-register, and some don't at all. There's literally more old cars on the roads than modern cars. There are lots of things to see and do. I won't go into details, look it up if you want to see what its all about. What's important to me is they autocorss for 3 straight days. While I can't make it all 3 I did go for about half a day. The rain prevented me from continuing to try shock settings at Moparty, so this would be the first time with a new shock setting I wanted to try and my new found confidence in the car. They have race trucks there giving people rides that have full race chassis with 315s all around and 700HP LS engines. They were doing the course in 36.***. After a couple runs I was getting in the high to mid 39s consistently. I ended the day with a 38.8ish. I know I left some time on the table because they had a full circle at one point of the course and my sure grip was not happy about it. I couldn't lay down any speed in that part of the course.
In summary, for me to be only a couple seconds slower than a race truck with big tires, big HP, and a driver that does this all the time, I'm happy with the performance of my 235 tires, non-containment seats, and OKish driving.... My knees are banged up from bracing myself on the console and the door! LOL!
So two trips to the coast this week with autocross, lots of driving (and sitting in traffic) have totaled about 400 miles on the car and its running great. This is also the first time I actually did any substantial driving since I installed the HDK. It's a firm ride, but not beat your teeth out firm. It rides over bumps in the road and expansion joints in bridges nicer than my truck!
In summary, for me to be only a couple seconds slower than a race truck with big tires, big HP, and a driver that does this all the time, I'm happy with the performance of my 235 tires, non-containment seats, and OKish driving.... My knees are banged up from bracing myself on the console and the door! LOL!
So two trips to the coast this week with autocross, lots of driving (and sitting in traffic) have totaled about 400 miles on the car and its running great. This is also the first time I actually did any substantial driving since I installed the HDK. It's a firm ride, but not beat your teeth out firm. It rides over bumps in the road and expansion joints in bridges nicer than my truck!
racerjoe
Well-Known Member
I did. For reference, I ran all my autocross runs at Cruisin the Coast on 13 compression and 14 Rebound and for the "Cruisin" part I put them at 6 & 7. I haven't bothered tinkering with the cruise settings much because I was happy with my first choice. (At Moparty for the drag passes, I did go full loose on the rebound and left the compression tight.)
I am starting to think I need to try a 450lb spring and maybe tighten up the shocks more on the course. This course had a few really fast offset slalom type curves and I could feel the car rolling a bit. If the car was flatter, it would have been easier to navigate through those sections. And now after having double adjustable shocks, I want some for the rear! Where have these things been all my life...
Side note, the fairly even tire wear is impressive. The insides edges of the front appear to be doing work just like the outside edges. This further validates the temperature measurements I took at Moparty. Maybe my alignment wasn't aggressive enough with the T-bars, but I never had tire wear this even before.
@HemiDenny I am planning on starting a new thread in the suspension section to compare and contrast T-Bar vs your kit once I feel like I have it sorted to the best of my knowledge level. So far, I have not been disappointed!
You likely rarely ever drive in the "old guys / coffee getter" plush mode. If you ever get old enough, you might even want to try a softer set of springs.
BTW....no disappointments on the HDK end either. Thank you from all of us for your honest feedback.
Denny
BTW....no disappointments on the HDK end either. Thank you from all of us for your honest feedback.
Denny
racerjoe
Well-Known Member
Finished off Cruisin the Coast with 550 miles on the car. It ran flawlessly the whole week. If you plan to drive your car at this event, your cooling system better be up to par. Besides the 85-90 degree ambient temps, you will sit in traffic. My car will maintain around 208 on a hot day and I did see 210 for a brief period, but it held there and came down immediately once we started moving. The cool thing about having EFI is it will add fuel to maintain the AFR once everything is heat soaked. Otherwise, it would have the same vapor lock problem as a carburetor. So the car runs the same at 210 as it would at 180.
Having never been to CtC before, I only heard of a very big Mopar meetup. So this was one of the places I wanted to attend this year. Little did I know there would be what appeared to be about 400 cars there. Here are some pics of the one that really caught my eye. There were others, but I didn't take pics.
Cool things to note on a couple of these cars.
The red 667 GTX has an RMS CoC with big brakes hiding behind those 17" steel wheels. Killer, super clean car.
The red barracuda is a bad *** car. EFI ITB on a G3 Hemi, custom chassis with Detroit Speed front suspension, huge Alcon brake calipers, and many other cool features. I never saw the owner, but I would have loved to get more information on it.
Nothing special in particular about the others. Can you tell I like Coronets and Road Runners...
Having never been to CtC before, I only heard of a very big Mopar meetup. So this was one of the places I wanted to attend this year. Little did I know there would be what appeared to be about 400 cars there. Here are some pics of the one that really caught my eye. There were others, but I didn't take pics.
Cool things to note on a couple of these cars.
The red 667 GTX has an RMS CoC with big brakes hiding behind those 17" steel wheels. Killer, super clean car.
The red barracuda is a bad *** car. EFI ITB on a G3 Hemi, custom chassis with Detroit Speed front suspension, huge Alcon brake calipers, and many other cool features. I never saw the owner, but I would have loved to get more information on it.
Nothing special in particular about the others. Can you tell I like Coronets and Road Runners...
racerjoe
Well-Known Member
Ordered some 450lb coil springs and I plan on hitting the local auto cross this weekend. I'm hoping this will be a good measurement if the car (and me) is working better since I know where I usually land compared to the regulars in their Miatas. The only problem is sometimes they make courses that are more favorable to them vs a big heavy car. Pax time is supposed to adjust that, but I don't who knows...
DionR
Well-Known Member
Hey Joe, what seatbelts are you running? I did a search and didn't find that you posted anything about that.
I'm debating about pivoting to a '73 Duster for my G3/T56 swap and leaving my Duster LA powered and more stock. One drawback to the '73 is the seatbelts, I like that the '74 has a more modern 3 point setup. Been kind of looking around to see if anyone has talked about what and how in regards to seatbelts and figured you always have good solutions to things like that.
I'm debating about pivoting to a '73 Duster for my G3/T56 swap and leaving my Duster LA powered and more stock. One drawback to the '73 is the seatbelts, I like that the '74 has a more modern 3 point setup. Been kind of looking around to see if anyone has talked about what and how in regards to seatbelts and figured you always have good solutions to things like that.
What’s the motion ratio on the HDK?
Yeah that’s definitely the problem with some of the AutoX club stuff, the course can sometimes be tailored to the club setting it up. Muscle cars on a Miata track is tight!
‘73 should have a shoulder belt anchor. Does that ‘73 still have the detachable shoulder belt that hooks to a stud on the lap belt?
My ‘72 Challenger had that style, I replaced it with a 3 point retractable belt from XV. In my ‘74 Duster I ditched the factory 3 point belts and replaced them with a set from seat belt planet? I think? I have the specs somewhere, you just need to specify the shoulder drop, the overall length and the length of the buckle riser.
racerjoe
Well-Known Member
I got them from seat belts plus. Pretty much just took a chance with them and they are pretty good. It does rub my neck a bit but not terrible. I chalk it up to being old car problems since modern cars have adjustable heights now.
1971-74 Mopar A B E Body Seat Belts - 3 Point Conversion - Bucket Seats - Starburst Buckle
racerjoe
Well-Known Member
https://www.seatbeltsplus.com/product/3-7174-E-BodyBu.html
I need to educate myself on how to measure/calculate motion ratio. I’ll have it apart tomorrow to change out the springs so I’ll do it then and report back.
Yeah with the motion ratio you’d be able to calculate the wheel rate, so you’d be able to compare it to similar Mopars with torsion bars. This is a decent explanation
Spring Rates Part 1: The Motion Ratio
And RideTech has a full on calculator for calculating spring rates based on corner weights, etc. But one part is that is a decent schematic showing how to measure motion ratio
Spring Rate Calculator - Ridetech
For @DionR, my seat belts are in fact from from seat belt planet. They’re a custom set because they didn’t have an application for a Duster at the time, they’re 140" length, 12" sleeve (bucket seats), 8" extension on the shoulder loop. I feel like they fit pretty well with placement of the belt for me anyway.
3 Point Retractable Seat Belt with All Metal Push Button Buckle
racerjoe
Well-Known Member
I got impatient and went out and took some measurements this morning and used the ride tech calculator.
Note: I estimated corner weight based on a total car weight of 3500lbs with me in it. I haven't weighed it with the HDK setup (scales at Moparty were backed up). It was previously 3535 with me and t-bar suspension. I also lost a couple lbs since last year...lol. I also guess at the unsprung weight.
I used a few different corner weights, based on front/rear balance percentage to see how the results would change.
Motion Ratio = .807
55/45 = 400lb spring rate
56/44 = 425lb spring rate
57/43 = 425lb spring rate
58/42 = 425lb spring rate
59/41 = 450lb spring rate
60/40 = 450lb spring rate
Changing the unsprung weight just bounced these results between 400 and 450.
It looks like I did a good job guessing on the initial spring rate and ordering the next size up, 450lb. (sometimes its better to be lucky than good) QA1 doesn't have a 12" 425lb spring. I'm sure I can find another brand, but I doubt it will make much difference, especially since my weights are guestimates. If it's too much and I get some oversteer, I can always loosed the rear bar up. It's full tight right now.
DionR
Well-Known Member
Yep, has the shoulder belt anchor but they are the detachable shoulder belts. At least I don't have to build an anchor in the roof.
1974 was the first year for fully retractable seatbelts, but was kind of clunky in their application due to a ratcheting mechanism. 1975 was better as they went to an inertia mechanism, and it is a bolt-in to a 1974. At least, as I understand it.
Thanks!
Perfect.
Started working on trying to buy the '73 so unless the deal falls through I will almost certainly have to do something like this.
DionR
Well-Known Member
Do either of you have any pictures of the seatbelts as installed? Then I will stop mucking up your thread, Joe. Thanks!
racerjoe
Well-Known Member
I believe at some point the retractable mechanism was recessed into the rear panel, not on exposed on the floor. Perhaps this was in 73 when they changed the interior panel design to plastic??
racerjoe
Well-Known Member
No worries. I'll grab some for you.
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