Modifying an IROC Fibreglass Bumper

[will hung]

Hey Mark,

I have a dumb question, and in making a picture to illustrate my question, I noticed a detail on your car, so I also have a comment.

First, the question, since you used a mold of the factory front valance to fill in the oil cooler opening in the IROC bumper, how does the height of the factory valance compare to the IROC bumper. Is it shorter, taller, same height? I'm talking about the measurement illustrated by the red line in the picture of your car below.



While resizing the picture and adding the red line, I noticed your mirrors. Very nice. I like the way they look a lot. Do you like them from a functionality standpoint?

Thank you,
Bill

[SilverWT]

Originally Posted by will hung

Hey Mark,

First, the question, since you used a mold of the factory front valance to fill in the oil cooler opening in the IROC bumper, how does the height of the factory valance compare to the IROC bumper. Is it shorter, taller, same height? I'm talking about the measurement illustrated by the red line in the picture of your car below.

While resizing the picture and adding the red line, I noticed your mirrors. Very nice. I like the way they look a lot. Do you like them from a functionality standpoint?

Hi Again,

The height of the "valence" area on the IROC bumper I used as a starting point is the same as a factory valance plus the rubber spoiler lip. The filler piece I moulded from a factory valance did not fill the hole all the way down, but as it was a narrow gap it was easy enough to face it with some card and lay the FG up behind to fill it.


Mirrors are Vitaloni Sebrings on modified Cup bases. Functionality is fine, although not as much visability as the Cup mirrors I used before.

Mark

[will hung]

Mark,

Thank you for the speedy reply. So you have similar clearance to a stock front bumper, exactly what I wanted to hear.

I figured you used Cup bases. I think they look cleaner than flag bases. I built a 3D printer and I want to use it to print a low profile base for my Vitaloni's that just covers the holes in the door, but have a similar profile as the base of the Vitaloni. I'll make my own gaskets. I plan to sand and paint both the bases and Vitaloni's to give them a nice finished look, as you have done.

Thank you again.

[SilverWT]

Originally Posted by will hung

So you have similar clearance to a stock front bumper.

Yes, similar clearance to stock without including the splitter, about half an inch less clearance including the splitter.

Mark

[DocG]

I have always felt the same way about the IROC bumper. I don't mind the oil cooler but it does protrude a little too far. Have you thought about making these. Hint, hint.

[RSBob]

Outstanding work with a designers eye for scale and proportion. Excellent

Just thinking out loud... To retain front impact properties, it would be fantastic if some one would develop a fiberglass skin which would slip over the original bumper up to the hood,Replace the lower valence and extend back to the wheel wells deleting the bellows similar to the design above. I would think it could be bonded to the original bumper with some adhesive. The little rubber smile between the hood/bonnet would also be deleted.

[Doug&Julie]

FYI Rothsport here in Oregon sells the SCRS bumper for narrow or wide cars. Not cheap! But the only US option at this point.

Welcome to Rothsport Racing - Products

[DocG]

I have seen those, but the thing I like about this is that the bumper does not protrude out as far as the original IROC bumper. I also like the round openings for ducting.

[Number1_dog]

I like what you have done, and I see that I am not the only one who can't keep things simple. I am a fan of the look of the long hoods. I am in the current process of working on a long hood rear fiberglass bumper for my 1979 SC. The early bumpers, just like your bumpers have a distinctive bumper line, that goes in an inch to complete the bottom portion. I want to fill that indentation in and have a smooth curved contour without the distinctive bumper line. I saw a 1967 912 this weekend at autocross and I noticed that its bumper juts out by a an inch or so from the body so I may have to also shorten the bumper on each side so that if flows better with the body. Like Stan Towes 911 Speedster, but I want to keep the middle section of the long hood. I am thinking of doing a fiberglass 911S front end and doing the same thing and maybe graft on the front spoiler from my current front end.

Lets keep modifying the best car to own !!!

dog

[SilverWT]

Thanks for the various positive comments, unfortunately I am currently having to rebuild the bumper after some impromptu crash testing.

A combination of a wet track, over enthusiasm, a pit wall and just about 90mph meant I went from this...

... to this ...


This was a couple of weeks ago and the reassembly is well under way.

I had a helmet camera running at the time, it was a bit misaligned, but you get the idea from what it showed.

• Out of a corner with the rear end settling and griping fine.
• Increasing power on the exit heading towards the pit straight still feeling settled.
• Just as I reach the exit point and 6,000 rpm (at 22 second in the vid) the back moves.
• I keep the power on and steer in, but there is not enough room between me and the start of the pit wall.
• Bounce off the wall, full on the brakes, full 360 and there's that wall again.

All part of the game I guess!


Oh dear - YouTube

[DocG]

Hope you are OK. It was hard to watch the video. The bumper seemed to hold up well.

[SilverWT]

All fixed now!


Mark

[will hung]

Good to hear. I'm digging the blue centered Fuchs.

[Clay.0]

Originally Posted by DocG

Have you thought about making these. Hint, hint.

I'd be interested in the filler piece if you were to make a few. Love the look of the bumper, good job!

[brcorp]

Great video!! Crashes always seem to look slowmo from the driver's seat!! Thought for sure I'd hear an Oh Shat!!!

[esonefour]

I love your style this car is such a one off piece of art.
that last hit is like the walls full stop! Glad it was a easily fixed.

[Andy Somogyi]

Looks great!

What are you using for bumper seals, that looks like a 964 seal/smile up front. Any issues with the fit?

What seals are you using for the rear bumper ?

[3rd_gear_Ted]

Form = (9.64), fit = (10.0) and function (pure Porsche )
Tastefully done

[SilverWT]

Originally Posted by Andy Somogyi

Looks great!

What are you using for bumper seals, that looks like a 964 seal/smile up front. Any issues with the fit?

What seals are you using for the rear bumper ?

Yes, 964 smile. The fit is good, but the bumper was shaped slightly in that area to improve it.

[SilverWT]

Originally Posted by 3rd_gear_Ted

Form = (9.64), fit = (10.0) and function (pure Porsche )
Tastefully done

Thanks