Has anyone used or heard of Bilstein’s AK series shocks. Looking to go non-adjustable, but wanting a more hard core performance shock. I have basically 550lbs springs in the front and 400 mono leaf in the rear. Talked to QA1 and their non-adjustable “sports” are just a littler firmer than stock… So that is no bueno… Afco makes fronts but not rear shocks for C3 Corvettes… Koni STRT’s are also OEM plus… So that circle backs to Bilstein. Only issue with the Bilstein’s is that I would have to cut off the t-bar on the bottom and tread on an rod end at the top.

 

I dont think they are avail for C3 Vettes

 

Yep, they are not technically listed for C3 Corvettes. However, they have the correct length for C3’s. Front and rears both have a 14” extended shock length. I could actually go slightly shorter as mine has been lowered 1.5”.

When I talked to the guy over at AFCO he actually referred me to their ‘70-‘81 Camaro front shocks. He said they would fit a C3 Corvette. All of their rear shocks are too long to fit our cars.

 

The AK series price wise seems to be comparable to their B6 - B8 series so, why dick around with an unknown quantity. JMO.

 

That’s what I’m wondering. If a B8 has similar compression and rebound rates then I’ll go that direction.

 

I'd go even further, and suggest that instead of solving the problem twice, just go with single or double adjustable shocks in the rear, and semi coil-overs in the front (single or double adjustable), and be done with it.

 

The collapsed length is much more important than the extended length.
When the shocks collapse they can bottom out internally, under load, on a bump.
Then it rides horrible.

My lowered S-10 did that, and it rode horrible. I just lowered the rear lower shock mount to prevent that, and now it rides smooth almost like a Caddy, the crashing is gone.
My bumpstops were hitting and the shock was bottoming out.

What concerns me on my C3 is my single adjustable QA-1s will bottom out, at or before the T/A hits the bump stop in the rear. And I did want to lower it, but not sure I can.
I only have like 1.5-1.75" of travel in the rear until the bumpstop and the shock bottoms out. It doesn't seem like enough. I had 2.25" in the S-10 when it was bad, it took 3.5" to stop the crashing.
The C3 has much less than that to start with, but it is also IRS, not a solid axle. I need to investigate more. As long as it does not hit the bumpstop I should be OK. I think.

CraigH went thru this in Australia when he lowered his 71. His coil over shocks were too long when collapsed.

Check your bumpstops carefully for bottoming out if you have lowered your car. Some grease will do. Or an aluminum foil ball.

 

If anyone is curious, I went with Koni Classic single adjustable shocks. Made a HUGE difference in the handling. I had KYB’s on it before, and the car bounced terribly as they were waaaay too soft. Feels more like a modern car now. Front springs are now roughly 560lbs (1.5 coils cut off a 474lbs MOOG spring). Front shocks adjusted 1/2 turn away from their stiffest rebound setting. Rear spring is 400lbs mono leaf with rear shocks also adjusted 1/2 turn away from their stiffest rebound setting. The car weighs 3,170lbs without driver.

The ride is not stiff at all. Just slightly firm.

 

Part numbers?

Thinking about new shocks myself. I have 550# front coils and a 400# VBP rear spring.

 

Koni Red "Street" Single Adjustable Classics have a fixed compression valving, which is set for a decent ride quality.
When you adjust them you change the Rebound only.
This needs to be valved stronger to control the extension of a stronger spring, or you get the pogo effect.
It sounds like you have to adjust the Konis pretty close to their limit to handle the 550/400# springs.
But that is OK.
I am glad to hear that they work with these moderately stiff springs!
Many of the other Single Adjustable shocks adjust both compression and rebound at the same time.
The increased Compression valving makes it ride worse as you crank up the settings.
That does not happen with a Koni.
On the singles the compression is set to handle either stock or sport handling style springs.
They pretty much always ride great.

I attached a Koni Shock Tuning Guide.
It is primarily for double adjustables, but can be used with others.
It is one of the best explanations of tuning adjustable shocks that I have ever run across.

You could also use the descriptions mentioned to determine if your current non adjustable shocks are up to "snuff".
Anytime you change sway bars or spring rates it affects the shock tuning requirements.
C3 #s Koni Classics (Single-Adjustable)
8040-1019
8040-1020

Grassroots Motorsports says the Bilsteins have stiffer compression valving.
So the Konis should have the ability to ride even better than the Bilsteins.

 

[/QUOTE]
Many of the other Single Adjustable shocks adjust both compression and rebound at the same time.
The increased Compression valving makes it ride worse as you crank up the settings.
That does not happen with a Koni.
On the singles the compression is set to handle either stock oro sport handling style springs.
They pretty much always ride great.

I attached a Koni Shock Tuning Guide.
It is primarily for double adjustables, but can be used with others.
It is one of the best explanations of tuning adjustable shocks that I have ever run across.

You could also use the descriptions mentioned to determine if your current non adjustable shocks are up to "snuff".
Anytime you change sway bars or spring rates it affects the shock tuning requirements.
C3 #s Koni Classics (Single-Adjustable)
8040-1019
8040-1020

[/QUOTE]

Yep, that is exactly what I was worried about. I didn’t want a crazy stiff shock that made the ride harsh in which it takes all the movement away from the spring. I wanted a shock to be able to control the spring. The softer compression should hopefully get me around corners quicker when I start to do parking lot races. I took out the rear sway bar to “loosen” up the chassis as well.

 

Many people online here love the ride from the non-adjustable Bilsteins.
Probably one of the best tuned shocks around for our cars.
But they have two stiffnesses for our C3s.
Do a thread search to be sure. But I believe the B6 works well for stock springs.
The stiffer B8 works well for gymkhana / f41 springs.
Many also run the B6 on the front with the 550# springs with good results.
But it seems unanimous that the B6 does not work well with the aftermarket glass springs.
For that you need the B8.
Those have less friction and need the stiffer valving of the B8 to prevent the pogo effect during rebound.

 

I had a set of Koni 'Classics' on the shelf for years. My BB '68 'supposedly' has the F41 suspension option - so front/rear spring combo......but damping was getting a little 'soggy' so I removed the existing shocks (which were actually old Monroe or similar - rather than GM F41 originals).
TBH I wasn't very happy with the performance of the new (old stock) Koni's and wondered whether it was due to the wider 18" wheels and tyres. However later inspection of the two front Koni's showed one with virtually non-existant rebound damping.
I subsequently installed a set of used non-adjustable KYB's which seem to work very well in conjunction with my larger diameter/lower aspect ratio wheel/tyre combo.
Ironically my buddy who passed the KYB's over has fitted a set of the Bilstein Sports which (he said) was an improvement over the KYB's and less harsh!

 

Honestly, every thing I’m doing now (engine, trans, suspension, wheels/tires) is on the cheap because I want to see what works and how it works before I totally jump in head first (for example in hindsight, should have went with a 600lb front spring). In the future the car will have a full road race suspension, but I don’t want to pay for a $10,000 suspension and then say… “I don’t like it” only because I don’t have the knowledge to know what I’m doing.

I basically have to crawl before I can walk….

 

The DSE suspension has vastly improved geometry.
It might be expensive but I cannot believe anyone would not "like it".
BTW it is $10 k per end. But it is the best.

A Vansteel street setup with basically improved stock parts is a good stepping stone.
Bilsteins seem to be one of the very few non-adjustable shocks that work very well on our cars in a performance situation.
There are also Ridetech, Koni and QA1 performance oriented non-adjustables.
I would search for reviews on those before you buy.

 

Have you heard anything about the new Hotchkis setup? Dates seems to be sliding to the right with no new release dates out yet.

 

I see development updates - kind of, on their website. But nothing yet.

 

Yeah, I emailed them last year.

When I contacted them in Jun, they said August or September.

When I contacted them in October, the response was "we have some final touches to finish up" with no date.

 

Last time I talked to them it was two custom made parts holding them up.
They need brand new steering drag link bars and rear outer axles cast & forged by subcontractors.
The prototype parts were cut out of billet.
The new drag link is needed to cut the bump steer to zero.
The rear outer axles are needed to mate the C7 bearing/hub to the C3 axles and u-joints.

 

Interesting. RideTech is already offering C7 hubs in their C3 trailing arms. You have to use C5/C6 calipers though. Strange makes their axles for them so you can use stock half shafts.
https://ridetech.com/product/offset-...1979-corvette/

I like the idea of the new drag link. Ridetech uses a bolt-on adapter to move the inner tie rod position and I don't think that will clear my Milodon pan. I have been running the old VBP bump steer blocks for 10 years and they have worked well for me so far.

Personally, I was interested in the Hotchkis setup but sounds like my investment in Tom's axles and Wilwood D-8 calipers will be null and void. May look at a different solution.