73StreetRace

I finally changed my old stock C3 seats a few days ago.
You probably know that many aftermarket seats won't fit the C3 corvette. Only a few of them will.
First, you have to decide if you want to keep the stock seat belts or of you want to go to a 4, 5, 6 point harness.
In the last case, you will need a harness mount bar behind the seats that will mostly block the way to that area.
Also, remember that even if you don't intend to use the area behind your seats anymore, the battery is still behind the driver seat...
So, a recliner seat in a C3 is much more practical than a fixed-back racing seat,
and often more comfortable too, especially if you're 6'1" and 200 lbs like me, because they are also narrower ( deeper side bolsters )...
The seat belt light will also stay on if you don't use the stock seat belts anymore. You will have to find a way to turn it off,
even if it's not a big challenge !
Also think that most bucket racing seats have side attachment points instead of classical bottom fixing.
All of them are not street legal too.
What's more, C3 interior is relatively small compared to many other cars. Any seat wider than 51 cm = 20" ( floor width )
will give you some issues with the seat belts and closing the doors.
At the shoulders level, it should not exceed 54 cm = 21,25" wide for the same reasons.
About the height, 93 cm is a maximum, except if it's a convertible car, otherwise the top of the seat will hit the roof during the reclining process.
I know that C5 seats are a good replacement choice. But it's not the same budget, and they are hard to find in Europe...
One last thing to know : a smaller steering wheel is highly recommended with aftermarket seats, or you will have some issues to get in and out of the car...

Having said that, all these considerations led me to choose the following OMP Tuning DESIGN II seats :

http://www.tuningracingcars27.com/si...i-p-18382.html

The dimensions on the picture are in centimeters.

The SRACING KIMI was nice too, but too small for me. It almost has the same dimensions as the stock C3 seat :
( pictures are small, but zoomable )

http://www.mtk-tuning.com/zoom.php?ref=4592

MOMO, RECARO, SPARCO, PRORACER, ORECA, amongst others, also sell similar products.

I also bought two universal seat sliders like this one :

http://www.tuningracingcars27.com/gl...rd-p-7149.html

So this is the first step : Choose a seat design and check that it will fit your car !
Now, here's how I proceeded, step by step...

1/. Remove the shoulder seat belt from the back of the seat. Use an hair dryer until the flexible plastic protector is soften enough.
This will allow it to go through the seat easily.

2/. Push your seat all the way back to remove the two front bolts on the seat brackets, then slide the seat forward,
recline it and remove the two rear bolts. Then remove the seat from the car.
There may be some rust on these bolts if you never removed them, so try not to break them !

3/. Then I made a pattern with a 20"x20" steel metal sheet ( 1/8" thick ). With the stock seat on it, I drew the four bracket holes,
then I drilled them, two 9/16" diameter front and two 7/16" diameter rear. This is the exact size of the punched holes of the stock seat brackets.
Bolt your old seat on the pattern with 4 bolts ( 2 x 9/16" + 2 x 7/16" ) to check that everything is OK, then remove the seat.
This pattern will be used to make the brackets for the new seats. This is the best way to be sure that they will bolt on directly in the car, and it will also be a great help to weld the pieces together and keep everything in the same plane.
Here's a drawing of the pattern :




4/. The new brackets will be made of SS (A4). No rust issues, and much stronger than steel.
Here are the drawings of the front brackets, rear brackets and U-Shaped brackets, respectively :


The above picture is for a left front bracket. Right brackets are symetrical.





The following pictures will help to understand where and how these parts go...


5/. Another pattern is made for the new seats. This will ensure that the new sliders will bolt easily
on the new seats.

6/. The new brackets are bolted on the first pattern, the new sliders over, then the last pattern.
Everything is TIG welded, but MIG would be OK too. After welding, the new brackets are sandblasted and painted black, too.
The following steps are easy... and now the pictures :







The side thumbwheels and plates ( plastic ) have to be removed : They make the seat too large to fit the car.
They are replaced by aluminum plates, so the total width will be reduced by 2".
The seat will still be reclinable but inclination will not be no so easily adjustable ( metal plate has to be removed to adjust ).









The new sliders :















Sorry, last pictures are a bit dark... black is black

There is only about five millimeters clearance everywhere between the seat and its environment.
That is really close ! I knew it would be close, but I was a bit lucky, too !

I still have to find a good idea to keep the shoulder seat belt buckle in a place where it's easy to catch it...

Suggestions and opinions are welcome...

cottoneg

Excellent post.

How tall the drive is has always seemed to be an issue also. My Brother-in-law and I went to Pocono to run our cars in time trials. With a helmet on, his head actually stuck out the top of the car and they would not let him run. I fit, but I am only 5’11”. He is about 6’1”.

So while the seat may fit, if it had too much padding for your butt or the bracket adds height, it may raise you up to a point where your head hits the top of your car.

73StreetRace

I'm 6'1" too, and I only have 1" clearance between my head and the roof.
So, no need to say that with a helmet, it would be really close...
I would say that I'm just at the limit... So, don't try this mod if you're taller than I !
Even so, there is still some clearance between the sliders and the plastic box ( belt mechanism ) under the seat.
So you can lower the seat by 10mm by making the U-shaped brackets smaller ( make them 8 mm height instead of 18 mm ).

And if you remove the stock seat belts completely, I think it would be possible to gain about 1".
I have to say that the new seats are firm, much more than the old ones...
Perhaps the foam will collapse a little with time...

zarifian383

This came out very very nice, and am very impressed. It matches the rest of the interior, Definitely bookmarking this thread for the future.

Vicar

Wow! That looks really nice. Well documented post as well. I'm just refurbishing my old seats and needed some info on how to remove the seats - and there was your post.

I like the sporty steering wheel as well actually. Where did you get that from?
By the looks of it you did a lotta mods to your interior. Since I'm in the middle of re-doing my interior; do you have more posts or info on the other mods done to yours? I might wanna steal some of your ideas if you don't mind :-)

Grtz from the Netherlands,
Vicar

captl27

nice job enjoy

Highhat

Was there a weight savings?

DaveL82

I have the OMP seats also and couldn't get them low enough. They sit in the attic now.

I plan on giving them a second try this summer by removing some of the seat padding. I bolted the sliders directly to the floor and still had height issues especially for track days with a helmet.

Your install looks great!

snoopykissedlucy

Any chance that I can use the side **** trick on these Summit Seats and get them to fit?

I want the Summit Seats only because of their cheap price $134. Has anyone tried to modify these?
http://www.summitracing.com/parts/SUM-G1159-2/

Imo Apita

Very nice install, like the seats.
Snoopy, nice find at Summit, I've bookmarked these just in case I ever got any money left:
http://www.hyperautoparts.com/shop/c...r-p-70551.html

$289/pair..!

neuroclast

I ordered some Yonaka racing seats a few days ago for $460 shipped (synthetic leather?).

Wish I would have seen those at summit and hyperauto

lvrpool32

I think the issue with those summit seats is the width of the bottom cushion at the front bieng too wide and hitting the transmission tunnel and the width at the shoulders bieng too wide and hitting the door panel.

78aldo

I'm liking these Summit seats also.I checked the link and they even have them in a tan color that looks close to my interior.Lets hope some one chimes in that has used them.

snoopykissedlucy

Have I discovered lost gold?

I just pulled the door panels off and saw that there is easily 3 inches of thick foam in the door panel where the seat contacts it.

Has anyone tried to create a flat door panel or tried to shave it down to fit aftermarket wide seats?

Lastly, both Jegs and Summit sell seat slider adjusters for $30....much better than my rusty piece of crap.

http://www.summitracing.com/parts/SUM-G1153/

mydejavooo

Very nice!!

Deja

73StreetRace

Thanks for your comments !

Yes, OMP seats are lighter, even with the universal steel sliders.
About 14-16 lbs less ( 7-8 lbs per seat )

73StreetRace

As other people already asked me about this steering wheel, I will only give you the link of this old thread, where you will find some answers about it ( beginning at post #16 ) :

http://forums.corvetteforum.com/c3-t...r-console.html

mydejavooo

Nice steering wheel....but IMO it seems like a huge amount of effort for a steering wheel, when there are ones that bolt on, or ones that already have adapters made for the aftermarket wheel. Like I said...VERY nice, but too much work for a non-lathing person like myself.

Deja

MN-Brent

Sometimes its not about the effort vs end results, but the journey there.

If you keep the point of view that playing with these old cars is a hobby, then the sky is the limit to what you can do to it. Just keep it in good taste and have fun.

73StreetRace, love your interior set-up.