tempest

yes, there have been a few threads on this before.

http://forums.corvetteforum.com/showthread.php?t=768918
http://forums.corvetteforum.com/showthread.php?t=348230

i think a few people have installed them in the past year, and i'm looking to get a set (probably the QA1), so i figured i'd see if i can hear some "long term reports" from you all.

to summarize what i've learned from the past posts:

QA1
pros: lighter, adjustments are easily accessible, looks better (to some)
cons: dual-tube config more prone to foam/fade

Koni sport:
pros: monotube design, Koni knows shocks, period
cons: need to remove rear shock to adjust, heavier

the Koni's softest setting is harder than stock shocks, which could be a pro/con depending on who you ask.

since the only races i participate in are parking lot autocrosses, plus one that is a one-lapper around a road course, i figure the QA1's are the way to go. my car is also a daily, so the QA1's will also be able to be set to a stock-ish damping characteristic.

i guess if i could hear some input on the following i'd appreciate it:
- any QA1 failures or durability issues? (Koni failures???)
- fitment issues? (excluding the adjusters for the Koni's at rear)
- best vendors to get either of them?

i also have a more general adjustable damper question - do these two adjust damping for bounce, rebound, or both?

(DISCLAIMER: any resemblance of this thread title to any other thread, living or dead, is purely coincidental. )

mothersworry

65Z01

I have Koni on the rear of my IROC and would not do it again, as I have to remove the shock to adjust firmness...what a PITA.

USAsOnlyWay

I have a question for you, what do you mean, "more pront to foam/fade"?

Let's hear it guys I want to know the same info he does!

JrRifleCoach

I spent a day in the shop at Koni when they were located in Virginia. Got the grand tour and lots of good info on shocks and of course why Konis are the best. Of specific note is the method of applying the "gas" to the oil resevoir. Some mfgrs put a plastic bag of nitrogen into the oil chamber to keep the oil from foaming. Others like Koni put a gas charge into the chamber to act directly on the top of the oil. So the piston rod seal becomes the weak link in the longevity of the shocks life. A Koni seal holds back oil and gas. Throw a bag of gas in there and a cheaper seal can be used.

Which is the better shock? Both have their good points; QA's are externally adjustable, if your racing and need the convienience.

Which is less or more likely to foam? The Koni's based on the design will be less likely. If your racing you can build up enough heat to fade shocks.

The question you need to ask yourself is what kind of driving are you going to be doing?
Spirited street? Not likely to overheat a shock.
AutoCrossing? Need the adjustability.

-JRC-

USAsOnlyWay

Thanks for the clarification JRC.
From what I had read quickly, it seemed that the foam/fade was a product of heat/continual use...aka road racing. I wasn't sure though.

So it seems, if you want to auto-x/street/drag. With an emphasis on street, QA1s are up your alley.
If you are going to do road racing, its a hard slant towards Koni's.

So now it is back to the original questions:
As for the vendor one, the best price I have seen post shipping is Summit.
I am EXTREMELY interested in hearing the durability/rebuild rates for QA1s. I don't want to drop ~700 on shocks only to have to do it again 2 years later!!!

RAFTRACER

Koni sports, rebound adjustable only. QA1's rebound and compression adjustable , but not independantly(one turn of the **** does both). Don't know much about QA1's , But I have Koni's and they ROCK !!! I believe you can get independantly adjustable "doubles" from each company though, for added cost. At least from Koni you can.

VR'92

Which one is cheaper?

Solofast

The Koni's were developed specifically for autocrossing on a C4. I did the development driving for the ones on the 17 inch cars and we tested three different sets of shocks until we got it right. Roger Johnson developed the 16 inch wheel size. On a C4 you will end up near full soft on the rears and in the middle of the range in the fronts. You will be able to dial in the car using just the fronts. If you are getting push, soften them a bit or if you are loose tighten them up. I takes only a few seconds and is regularly done between runs. If you run out of rope on the fronts you can make rear adjustments but obvioulsy that takes longer. I have heard of some folks drilling a hole in the body above the rear shock hole and then they are able to adjust the rears quickly. I never did that but some people have and it seems to work for them.....

I drove the Koni's on the street for years, just run the fronts to full soft and they will be very comfortable. These shocks were developed around the z51, z07 suspension package for the 89-95 cars. Mark Presley and (as far as I know Matt Braun) are all using these shocks. I tested with Mark in April of last year and the car worked just fine on the Koni's (witness his second place finish in Topeka).

Koni's have low internal friction, that makes it less harsh, and actually improves the handling. Some other shocks (notably Bilsteins) use cast iron piston rings, which last well, but have a lot of "stiction" which makes them very harsh over small impacts and makes them uncomfortable on the street.

The Koni's will last for years and years. The set that I sold to Mark Presley were over 10 years old and had a couple of hundred thousand of street miles on them and they dyno'd about the same as new after all that abuse...

BrianCunningham

I've got the QA1's and I love them.

I do a variety of racing, autocross, road, drag, and it's also my daily driver, w/o thier adjustability it would be a lot harder.

They are both easy to adjust, and the range is large. 0 is basically OFF, where 12 is buckboard stiff.

loiq

With a twin tube shock design the oil and gas are separated usually by a bag - the gas is held in the outer tube of the shock and the main tube is filled with oil. The damping takes place when the shock piston travels through the oil and how the piston is set up determines the rates, but the gas bag in the outer tube also absorbs some shock. These shocks are not pressurized.

There are two types of monotube designs, emulsion and internal floating piston (I don't know which one the Koni's are) also called a deCarbon shock (named after it's designer). With an emulsion shock the gas and oil mix together in the shock body and "foaming" is actually a part of the design - these shocks don't work until the piston gets worked and the gas/oil combo mixes together. These shocks used to be the standard on most dirt bikes.

In the IFP shock the gas and oil are separated by an internal floating piston. These are perhaps the "best" shocks and are what high-end race cars rely on (off-road trucks, indy cars, etc.). The gas inside them is pressurized (nitrogen).

As for how fast each fade - the twin-tube will almost always fade faster. If you tried to ride a dirt bike with twin tube shocks it wouldn't last long. The rear shocks on most dirt bikes are IFP reservoir designs.

I'm no expert on shocks, but I know a little (just enough to be dangerous). Do an internet seach for shock designs and you will learn a lot.

JrRifleCoach

This is where the "best shock" conversation takes on a more subjective direction. What does the driver like? QA-1's are fabulous shocks. LOTS of valving combinations to choose from and rebuildable. There is a dealer in the Sacramento area (factory I think) that does this work. However, QA-1's cost more than Koni's. Roughly 150 per corner. Koni red's are 100 and the yellow sports are 130 give or take some.

So generally speaking, what do you want to do with your Vette? Race? Auto-X? Cruise? Daily driver? Park it? How much do you want to spend? (Actually this is a soft topic for me since many people will spend $2000 on tires and wheels and get all cheapo and buy kyb's )

I bought Koni Red's because I want the best street/spirited driving performance and not go broke doing so. When the time comes to get serious on the track, then I'll spring for QA-1's. No question in my mind......

LD85

What addittional cost is there besides the shocks?

Do they both or either or neither require welding to clear the frame, (I read that somewhere) or do neither? I have an 85 and would love to do this mod.

TIA

tempest

thanks for all the input.

i'm along JRC's line of thought regarding the "what is the best shock" question. after worrying this thread will just become a "mine's better" thread, i'm very happy to see all of the objective comments.

i'm leaning toward saving my pennies for the QA1's since i have two very different main uses for the Corvette (autox & daily driving).

off on a slight tangent, i will be getting poly bushings before i get the shocks. no sense in investing in suspension components unless the pivot points are any good....

LD85, shock swaps are quite simple for the two i am looking at - just swap em. i read one of the mounts on the QA1's is narrower than stock so a washer or spacer needs to be used - no biggie.

rocco16

No experience with QA's but the KONI Sports (yellow) on my '96 have given me no problems whatsoever and the installation was a breeze.
I've heard that installing the QA's can be problematic.

Larry
code5coupe

USAsOnlyWay

The adjustability is what I really want. Which is why I personally am leaning towards QA1s, mind you if Koni Yellows are actually 130$ (can you list a source), QA1s are only 5$ more through summit. So that is a wash.

My big questions personally are.

How long do they last?
How much to rebuild?

froggy47

I've had QA's for about a year & love 'em. Lighter, ez adjust, soft (well not that soft) for street & hard as you want for autox. No failures, you can (supposedly) rebuilt yourself. I paid about $125 per corner so IMHO price is not really a factor.

I had a new set of Koni's & QA's on my garage floor & could have gone with either. I just could not deal with having to REMOVE the rears if I wanted to try an adjustment.

They are double adjust with one **** so you do not adjust bump & rebound separate.

My only gripe is that the Koni's have a Vette specific package, with the QA's I had to fab the front bump stop (Koni's are built in) but it was easy to do. Also I did not like the fit of the grommets so I used new stock ones from Superior for a better fit. You could use your stock ones over & also use the Bilstein (if that's what you have) bump stop on the QA. It slips over the rod & just floats.

I would do QA's again if I got a new C4.

USAsOnlyWay

May I inquire where at?

LD85

Part numbers Please

USAsOnlyWay

These are from summit,
front: HAL-TC3014P
rear: HAL-TC3024P

140$ apiece