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View Full Version : Looking for more real world feedback on C4 conversions



55 Rescue Dog
01-09-2016, 02:55 PM
I have no idea how many C4 tri fives are out there, but I would really love to hear more real world feed back as to how great, not so great of a set-up it is? So far I have committed to a $3000 55, and $2000 C4 suspension. Ready to move on step 3, getting a conversion chassis. CED first choice. Just need to hear more from people that have actually driven them, or any others. I realize every set-up, or expectation is different. I just want to do it right. I want the best driving, handling 55 possible with the least issues.

WagonCrazy
01-09-2016, 03:28 PM
I have made the committment on my 57 Nomad, but (sadly) have not gotten it completely roadworthy just yet.
I think you'll be pleased with handling.
I have another 57 wagon with conventional suspension and it handles like....well...a 50's era tank.

On the Nomad build, I started out thinking I would use the stock Corvette batwing springs (front and rear) but changed my mind and went with a set of ViKing double adjustable coilovers. I wanted to be able to better tune the ride height, compression and rebound dampening, spring weight, etc.

I think you'll be pleased with yours. Keep going with the parts assembly...

chevynut
01-09-2016, 04:01 PM
RD, there are literally hundreds of these cars running around so it's a popular conversion. I think Newman has done around 500 or more of them since he started, every one of them with the stock C4 springs. There's also been a ton of C1, C2, and C3 Corvettes outfitted with C4 suspensions, as well as first-gen Camaros.

Wish I could tell you where to go to drive one of mine, but they're all too far away from you as far as I know. I'll bet there's some C4 tri5s in your area though, if you asked around. The best I could do is give you some phone numbers as I've offered before. What I recommend is that you to go drive a couple of C4 Corvettes...one early and one late. A tri5 with a C4 suspension and stock springs is going to drive similarly. The CG may be a bit higher but it should feel close to the same as far as road feel. It will give you a good idea what to expect.

To be honest with you I think you're asking for something you're not going to get. How is someone going to convey their feedback to you other than to say "I love it" or "I hate it" or "it handles great"? What does that mean to you? The only way, imo, that you're going to get your question answered for yourself and what you're looking for in a car is to drive one yourself. BTW, I have yet to hear anyone say anything negative about their C4 conversions, no matter who built them.

Maybe you should fly to California and drive Newman's 57 wagon ;). I had a friend do that after sinking thousands into his 57 front end, and he was instantly sold on it...so we installed a C4 front suspension in his car.

55 Rescue Dog
01-09-2016, 04:09 PM
I have convinced myself that the C4 is the way to go, but as you being a chassis builder, I can't help but wonder, and want to know...how many have you personally driven, and tested with all the different combinations, is what I'm looking for? HELP ME

chevynut
01-09-2016, 07:07 PM
RD, I regret to admit that I have not yet driven a tri5 with a C4 suspension :eek:. I realize that having done over 60 projects now, that sounds kind of weird. However, I got into this hobby-turned-business quite by "accident" and demand from customers. I did the conversion design and built my frame jig solely to build my own conversion chassis for my Nomad. When I started showing my progress on forums years ago I got calls and e-mails from guys asking me to build them a frame, so I did. One after another I got requests to build them and I did it part-time along with my regular engineering job. I retired a little over 3 years ago and the orders were still coming in, so I decided to turn it into a "legit" part-time business. I set up my website and we're still building them. I honestly don't know how much longer I'm going to do it but for now I have no plans to stop anytime soon.

Even if my Nomad was running and driving, I don't know what I could tell you that would address your questions. If I had driven a dozen of them and tested BBCs versus SBSs, automatics versus manuals, coilovers versus stock shocks, sedans versus wagons, early versus late suspensions, what is it you'd want to know? What if I said all of them are great and a huge improvement over stock? Sorry but I really am struggling with what you're asking for as far as feedback. ;)

All I can tell you is the feedback I've received from customers has been very positive. One guy built a 57 for his dad as a daily driver (in NJ) and he said the car "drives like it's on rails". Another (the blue Nomad in WV)) told me his drove like a modern car instead of a 50's car. Another (the silver and white 55 in Utah) told me his was "the funnest car I've ever driven". I thought I was going to get to ride/drive in the 55 a few years ago when I was at SEMA in Vegas, but we never got together. The owner was at a car show an hour or so out of Vegas. I don't know how many of my customers actually have running cars. Most of my customers are home-builders, not shops, though I have built a few for shops. I have seen several tri5s at local Goodguys events with C4 suspensions but have never asked the owners for a ride. Maybe I should. :)

I don't know what else to tell you. Kyle Newman was kicking butt in autocross against Camaros and Mustangs with his 55 and their 57 wagon when he was racing. To me that's proof of the performance aspects of the suspensions. Super Chevy did a test of Newman's 57 wagon a few years ago and it out-performed the 5th generation Camaro (2010). I still have that article somewhere. I don't know what else you're looking for, and as I said I don't think anyone can tell you. To me your question is kind of like asking for someone's feedback on a girl.....what's the question? Is it if she's cute? Sexy? Smart? Fat? Funny? And everyone has different tastes. :) There's nothing like first-hand experience, and I'd recommend you look for one to drive yourself. ;)

If you have specific questions, I can try to answer them. But to just ask for "feedback" is pretty vague. I can give you technical specs if that helps.

55 Rescue Dog
01-10-2016, 06:44 AM
I appreciate your responses, and sorry I can't be more specific. I realize that any chassis design will have different characteristics, and it is like trying to pick out shoes for someone else. Until you try them on, you just don't know. Just didn't know, other than making all the components fit, I was looking for what R & D testing was done on a chassis to make it handle the best, with nothing breaking. Oval track chassis builders never seem to build the same chassis twice. They are always tweaking something. Small changes in the design can make a big difference with testing. The tube frame Camaro I built, with no engineering drives/handles pretty good to me, but maybe no one else, and if I had to do it over, I would have made some changes, but had no idea how it was going to work until I drove it. I have been avoiding autocrossing it because I don't want to know what else I should have designed different that I can't redo. Just want a chassis that has been well sorted out, cost effective, and rock solid dependable.

rockytopper R.I.P 5-13-2017
01-10-2016, 07:10 AM
Dog just about all trifives street driven that have competed in any form of Racing use C4 setups. In your budget range your not going to find anything better. I believe my bolt on setup is going to get me close to what the c4 cars are doing but certainly want better it. Even with C4 there are tons of tuning options if you want to get serious I guess. Think spring rates you choose may play into. Rat Rod Russell who offer the DIY C4 frame have competed in AX. You might pick his brain to see what seems to work best etc... The best racing rate might not be to friendly on the street all depends on what you want I guess.

chevynut
01-10-2016, 08:26 AM
RD, as I have said before, my conversions maintain the stock C4 suspension geometry. I don't narrow anything unless requested by the customer and then only do it in the rear. That's why I suggested to go drive a C4 corvette if you can't find a C4 tri5. There's really nothing different between my conversion and Newman's or RR Russell's as far as geometry. I have noticed Russell's suspension installations in the past seem to make the car sit higher than it needs to, especially in the rear. I don't know what k-member height relative to the frame either one of them uses. When set up properly, the lower a-arm should be level or slightly down at the balljoint end, and the same with the halfshafts. I set the rear with halfshafts level in my jig and the batwing is as high as you can go without notching the frame.

Here's a recommendation for you. "Jims57" on the other site has a Newman chassis and he's been driving his car for a couple of years or more. You should ask him for his opinions and feedback on it. He's a self-proclaimed liberal so he doesn't like it here with all of us conservatives and racists. ;) His k-member bolts into the frame and I don't know what ride height his is built to. Newman's frames don't allow for coilovers, at least in front, so he is using the stock C4 springs.

I don't think anyone here has ridden in or driven a C4 conversion tri5. Mick (bowtiedownunder), Steve (Bluegrasstrifive), and Brian (Custer55), Paul (wagoncrazy), Mike (Fladiver64), and Arend (Willawog) are all still building theirs as I am. The last 3 are my customers.

chevynut
01-10-2016, 08:34 AM
Rocky, good post. ;) I'm not sure what all you can do to "tune" the C4 suspension, but certainly spring rates and shock tuning can be done. The pickup points for the suspension could be changed by modifying the rear camber brackets to change rear roll center or designing the dogbone attachment so you have multiple holes to use for anti-squat. You could also further lengthen the front spindle with longer balljoints if you wanted to, I suppose. But none of those changes (except the dogbone adjustability) affect the construction of the frame.

I'm personally not a fan of bolt-in k-members in these chassis. If you look at the C4 Corvette chassis there are 4 diagonal braces from the k-member to the frame to support it, two in the front and two in the rear. None of the bolt-in k-member chassis for tri5s that I've seen use those braces or any other bracing. I think the weld-in k-member looks better and actually looks like part of the frame. Personal preference I guess. :)

Custer55
01-10-2016, 10:42 AM
Rescue Dog, I have not driven mine yet (I hope to have it far enough along to test drive it by this spring) but we own a 90 Corvette which I drive a few times a year. The C4 Corvette has excellent handling and a nice tight feel. Like most people I'll probably never push it anywhere close to it limits. (maybe 75% to 85% of what it can do) It can go around a 30 mph off ramp at 65 to 70 mph without a problem. As far as ride quality it is pretty good on a smooth road, but you will feel every bump in the road. Tires also have a big impact on the ride. When we replaced the original Goodyears with a set of Falken FK 452's the ride was much better, night and day difference. I'm sure shocks can make a big difference also.
Hope this helps.
Brian

chevynut
01-10-2016, 11:08 AM
Brian, have you ever driven an early C4? Is there a noticeable difference in handling compared to your late one? They had various springs available even in the late C4s.

I've heard the early C4s ride rougher than the later ones, but that may be due to the Z51 suspension that was used in 1984. The Z51 spring is a lot flatter and thicker than the later springs and is sought after by C4 autocrossers. I have seen a few that have a lot more curvature to them indicating they're softer springs (lower rate) and they were used in later C4s. The springs tended to get softer in later years so not all cars are the same. All the rear springs are interchangeable, but the front springs apparently are not.

And you're right about tires contributing to the ride quality. However, my Porsche has 225/35-18 and 275/30-18 tires and I think the ride quality is excellent, for a sports car. It's firm and responsive, but not rough imo. A 4" sidewall height is about as short as I would go.

Rick_L
01-10-2016, 12:22 PM
Cnut, how about the springs on a 91 Z51? A friend of mine had one a good while ago - I thought it rode very rough.

chevynut
01-10-2016, 12:53 PM
Rick, any Z51 suspension is a "sport" suspension and they ride rougher than the standard FE-1 (or other) suspensions.

According to the spring charts I have there was no Z-51 suspension option in 1991, but there was in 1990 which was the last year for it. A 90 Z-51 had a front spring with a rate of 660 lb/in and a rear spring rate of 327 lb/in. In contrast, the FE-1 suspension (and some others) had a 522 lb/in front spring rate and a 228 lb/in rear spring rate.

So it's clear that you can't just ride in a C4 and make judgements on it without knowing the suspension option it has. Some guys like a stiffer ride and some guys like a smoother, softer ride. It all depends on how you want to use the car too.

Custer55
01-10-2016, 01:26 PM
I have only driven our 90 Vette so I don't know how the ride is compared to an earlier model. Ours is just a base model also, not a Z51 option. I have heard the 84's had a really rough ride compared to the 85 and up.
Brian

rockytopper R.I.P 5-13-2017
01-10-2016, 02:37 PM
Cnut does your frame design allow the customer to use the stock springs but allow a change over to coilovers if they decide they want more adjustability and can afford upgrade down the road or do you need to know up front one or the other just curious?

Rick_L
01-10-2016, 03:47 PM
I am not clear on the year, may have been a 90. I do know the car had the "sport suspension" option, which I thought was Z51 on all years.

The owner was a coworker, and we'd occasionally go to lunch in it. A couple of the roads near our workplace were pretty rough and that's what formed my impression of the car's ride. The rough ride was dramatic compared to just about any other vehicle on one particular road.

rockytopper R.I.P 5-13-2017
01-10-2016, 04:19 PM
I found this info. I read customer feed back made GM soften the ride after the first year. Factory racing increased it in latter years of the C4.

http://www.corvetteforum.com/forums/c4-tech-performance/3612068-comparing-spring-rates-84-96-z51.html

55 Rescue Dog
01-10-2016, 04:30 PM
Whatever set up I go with, if I had a 55 that worked as good, or better, than my 96 Impala SS, I would be all over it! They just missed it by not looking like a tri five. The best full sized GM car they managed to build, and then they switched the assembly plant to trucks. My 97 C5 is ok too. Looking for the best of all three.

chevynut
01-10-2016, 05:05 PM
Turns out the 1991 Z-07 suspension option used the same springs as the 1990 Z-51 and they were the stiffest springs used on any of the C4s with the exception of the '84 Z-51 which had a 500 lb/in rear spring and a 583 lb/in rear spring. By 1996 the base suspension (FE-1) had a rear spring of 149 lb/in with a front spring of 343 lb/in.

chevynut
01-10-2016, 05:07 PM
Cnut does your frame design allow the customer to use the stock springs but allow a change over to coilovers if they decide they want more adjustability and can afford upgrade down the road or do you need to know up front one or the other just curious?

Yes, our shock mounts are designed for eyes on both ends so coilovers or standard shocks can be used front or rear. You can go either way with it.

Rick_L
01-10-2016, 05:34 PM
Turns out the 1991 Z-07 suspension option used the same springs as the 1990 Z-51 and they were the stiffest springs used on any of the C4s with the exception of the '84 Z-51

Ok that makes sense.

rockytopper R.I.P 5-13-2017
01-11-2016, 04:42 PM
Rescue this one is setting on C4 AM frame 700 ponies on board it ran the go cart course very well.
http://i282.photobucket.com/albums/kk243/rockytoppers1/IMG_2783.jpg

chevynut
01-11-2016, 05:48 PM
this one is setting on C4 AM frame

Rocky, I don't think AME makes a frame for C4 suspensions. I don't know how their own suspension parts compare as far as geometry. They don't even make a tri5 frame with C5 components like they do for Camaros and other cars.

I'll bet 700 HP makes that thing move pretty well. Nice car, but I think the wheels are just a little too big for my tastes.

Rick_L
01-11-2016, 06:52 PM
As you probably know, AME does make an IRS suspension which will fit their frames or others. It's similar to the late model Camaro stuff in that it uses hubs from those cars but the rest is custom. I think it has a Strange 3rd member, don't know the details.

chevynut
01-11-2016, 07:02 PM
Yes Rick, I'm aware of AME's IRS. I get a catalog from them and it was in it months ago. It's pretty awesome in design, construction,...and price. I understand it's a $9K adder to their frames. :p I guess to those who don't mind throwing their money around it's not a big deal.

chevynut
01-12-2016, 06:10 AM
RD, here you go...real-world feedback: :)

http://www.superchevy.com/features/sucp-1003-newman-car-creations-1957-chevy-210-wagon/



RESULTS
'57 210 Wagon
'10 Camaro


Skidpad:
0.85 g
0.85 g


Slalom:
46.56 mph
45.84 mph


Autocross:
46.72 sec.
46.32 sec.

WagonCrazy
01-12-2016, 08:33 AM
Before I made the decision to have Laszlo (CED) build me a C4 frame, I looked around and asked alot of questions like you are doing Dog. I called up Paul Newman and spoke with him and he offered to take me for a ride in the 57 wagon if I was ever up in the central coast area. So I'm 4 hours from there, but my daughter was starting college near where his shop is, so I combined the visits and he took me for a 15 minute ride on a 2 lane road in the rolling hills east of Atascadero. I was sold on the C4 frame!!!! Dang, that ride got my juices flowing.

But Newman's frame setup was several thousand dollars more than CED's, and I couldn't see why I shouldn't give Laszlo the business. I think my frame was # 19 or so. He's done dozens and dozens by now. Alot of us buyers still don't have our Tri5's on the road yet, so we are the ones holding up his "word of mouth" on the actual performance end of the spectrum.

That's kind of a kick in my own arse to get mine on the road and start to autocross a bit with it. I put the 4 double adjustable coilovers on it because I wanted to be able to tune the suspension better than with the stock Corvette monoleaf spring. There's nothing wrong with starting with that monoleaf setup, and then switch to coilovers later on when you get the money. Just tell Laszlo (when you order your frame) that you want it set up for both.

And get the AME "center frame stiffener setup" (not calling that by the right term). You want to seriously reduce the frame flex. The stock frame will twist easily. Have him install this center frame setup and you'll have a very stiff frame.
Then you can really do some serious autocrossing! :cool:

5398 5399 5400

chevynut
01-30-2016, 12:56 PM
RD, don't know if you saw this comment on the other site, but I saw this today:

"This summer, at the Tri Five nats, I drove a '55 Sedan on a similar chassis with Corvette suspension and using the composite transverse (stock) Corvette springs and I thought it was fantastic.. Certainly the best driving, handling, feeling TriFive I've ever driven."

55 Rescue Dog
01-30-2016, 03:18 PM
That's great, but I sure would like to hear direct feedback from you driving your car, or another you designed! It's like buying a car sight unseen, without test driving it, no matter how great it looks, you don't really know until you see it, and drive it is all.

chevynut
01-30-2016, 03:38 PM
RD, I think you're missing the point I've been trying to make. I don't believe it makes much difference whose C4 conversion you drive because they're going to be about the same. The suspension geometries are identical between mine and Newman's, and even Nerd Rodz. We all use the same C4 k-member and same pickup points in the rear, same swaybars, and same steering rack. To me, it's like two guys bolting on the exact same suspension parts on their tri5s...how much different will they drive? I don't know why you would expect one to be much different than the other. SRG frames use different pickup points, rack, swaybars, and even different steering arms. I can't say how one of those drives.

One difference between my setup and Newman's is mine has the option to use coilovers or the stock spring and his doesn't. I think Nerd Rodz allows you to do that too but I'm not sure of that. I hear a lot of BS about how bad coilovers ride, but at the same time guys rant and rave about how good AME chassis drive. Guess what? They use coilovers on them exclusively.

I think the problem with coilovers is that most guys tend to over-spring their cars. They put a stiffer spring on it than they need to and it rides like crap.

I've offered to put you into contact with the guys that are driving cars with my frames. If you want to talk to them, let me know.