Repairing/restoring Renntech airfiler assy

[samiam44]

i've seen a few of these sold here- every one I've seen has cracking a discoloration.

Looking at the inside- there is no resin cracking. I easily peeled a piece of the clear off the outside. It came off quite easily(not epoxy bond for sure). I'm guessing it's a gell coat, but hopefully I can get some feed back next week.
If it's just the gell coat, I was thinking of peeling or using chemical stripper and then cleaning well/paint with urethane clear.



Michael

 

[gsxr]

Michael, this is very common... but I haven't heard of anyone finding a good solution yet. If you can remove the top (gel?) coat and re-coat with a hopefully more robust clearcoat, that would be awesome. My Feather Carbon airbox isn't cracking yet but the edges are discolored slightly (light yellow/brown) from summer heat. I tend to re-install the stock airbox during hot summer months to avoid further damage. There's gotta be some clearcoat that can handle temps above 200°F without failing!

 

[gerryvz]

I've had it on my to-do list to investigate this locally here in Houston, but haven't gotten around to it yet.

 

[samiam44]

DaveM,

If your cf airbox is just discoulored? Greenish tint is oxidized epoxy. That could be as easy as a good buff with rubbing compound. Then take it to a bodyshop and get it shot with clear.

 

[DerFuror]

Re: Repairing/restoring/destroying Renntech airfiler assy

Then take it to a bodyshop and get it shot with clear.

Or take it to these guys...
http://www.streetfire.net/video/destroying-my-sunspotted-carbon-fiber-hood-part-o_97776.htm

Or, for a more professional approach because calbon fibel is vely agglevating stuff...
www.i-am-bored.com/bored_link.cfm?link_id=57784

 

[gsxr]

DaveM, If your cf airbox is just discoulored? Greenish tint is oxidized epoxy. That could be as easy as a good buff with rubbing compound. Then take it to a bodyshop and get it shot with clear.

I've got two. The Feather Carbon box is all intact but the clearcoat or epoxy is turning a bit milky/opaque in very small areas. Doesn't look bad yet. I need to take a couple good photos.

The other box has the resin/whatever chipping/flaking off all over the place, it looks awful, lol. Turned a weird greenish/brownish color. See attached pic.

 

[gerryvz]

Yeah, that's largely what my Renner looks like, too.

 

[gsxr]

Interesting side note: The RENNtech box is larger/taller than stock, by roughly an inch, maybe a smidge more. The Feather Carbon box is twice as tall, i.e. approx two inches taller than stock. My car consistently exhibits the "stall during slow U-turns" issue with the supersize Feather Carbon airbox. I haven't used the shorter RT box enough yet to notice if the same issue is present with it, or not. Here in Spudland we don't often need to do U-turns (compared to most larger cities, where U-turns are a daily occurrence). I need to take some pics of the two next to each other for comparison.

 

[samiam44]

Dave,

That RT box looks worse than mine. By closer examination, I can tell you what ever was put on for to clear top coat ain't epoxy. It's too think to be paint... guessing it's gell coat. It maybe fairly easy to remove since the bondline has virtually no strength.
Any proveable performance difference between the factory, RT and feather airboxes? Or is it just eye candy for the local autoshow.

 

[gsxr]

I believe the airbox is strictly eye candy. There may be a sliiiight power gain but to date, I haven't been able to prove that. If there is a power gain, it's probably more applicable to larger engines (i.e., 6.0L). RENNTech claimed 10hp but I'd bet it's half that or less (assuming it's a positive integer).

 

[need2speed]

Anyone every try to claim warranty repairs or return to RENNTech (LOL) ?

 

[gerryvz]

I think when the RENNtech airbox is used WITH the RENNtech chip, you're talking major power gains of 20+ HP.

Either one by itself is <5 HP.

 

[gsxr]

Bad Gerry. No soup for you. NEXT!!

 

[samiam44]

I like that Gerry- that's synergy working for the engine. That's better than the straight addition formula famous on the bragging hot-rodders.

Just remember synergy only works on a Renntech engine. Negative power gain for all other users.


Michael

 

[gerryvz]

I really do think that's the value-added, implicit engineering that RENNtech brings to the table. 1+1=3, you know? Making HP from nothing. Seriously. All those pent-up M119 ponies that are just waiting to be freed from their corral by those awesome, expensive RENNtech go-fast parts !!!

It's like IBM in the old mainframe days. They would ship a top-of-the-line compute-power mainframe to the customer, but the IBM engineers would only "enable" the degree of MIPS (compute power) that the customer actually paid for. And they would charge tens and hundreds of thousands of dollars for an "upgrade" that would literally take a technician an hour or less to "unleash."

Little did the customer know they had a HUGELY powerful computer in their data center, just WAITING to be unleashed

 

[AS Design]

It discolors because they used polyester to make the part & over saturated it with to much clear jel coat rather than using automotive clear for heat & UV portection & Epoxy. Common problem.

Kind regards,
Albert S.

 

[gerryvz]

I'm wondering if RENNtech used that specific combination of polyester and gel-coating because it too offered significant horsepower and torque advantages over "normal" automotive carbon-fiber and epoxy combinations?

 

[AS Design]

I'm wondering if RENNtech used that specific combination of polyester and gel-coating because it too offered significant horsepower and torque advantages over "normal" automotive carbon-fiber and epoxy combinations?

Wouldnt make any difference in any way. If anything vacuum bagged carbon oven cured would be the correct way to go. Same reason why 100% of race cars use this combination for their parts. Reacts better to heat & is stronger, lighter, & a lot more thin. That's how I would do it.

Kind regards,
Albert S.

 

[gerryvz]

But wouldn't a gel-coated surface finish be (physically) smoother than other alternative varieties of finish on the inside of the airbox, offering less air resistance (and faster intake air flow) because of that smoothness? Seems to me that the irregularities of other types of surfaces would reduce airflow velocity. Sort of the same principle as mandrel-bent exhaust tubing offering better gas flow. I have no doubt that RENNtech would have paid high levels of attention to these details and their materials, given the extremely high cost of their products.

Cheers,
Gerry

 

[AS Design]

But wouldn't a gel-coated surface finish be (physically) smoother than other alternative varieties of finish on the inside of the airbox, offering less air resistance (and faster intake air flow) because of that smoothness? Seems to me that the irregularities of other types of surfaces would reduce airflow velocity. Sort of the same principle as mandrel-bent exhaust tubing offering better gas flow. I have no doubt that RENNtech would have paid high levels of attention to these details and their materials, given the extremely high cost of their products.

Cheers,
Gerry

Smoother inside would be better & easily accomplished when bagging the parts. As for the RENNtech box for the M119, it's just a simple wet lay-up process (cheapest way of doing it). I have one with me currently with the same issues ppl have posted. Haven't had the time to repair & make a mold off of it. But I hope to get around to it soon so I can show you a clean part.

 

[samiam44]

I think the Renntech box is all eye candy- but as noted it's a bit taller so the airflow doesn't have to make as high velocity of a turn. But there is no great shaping for airflow.

I'm convinced they used a cheapo polester gelcoat. I have yet to make it to the chem lab and check composition. I found some epoxy gelcoat which is clear like this : http://www.easycomposites.co.uk/products/epoxy-gel-coat/clear-epoxy-gel-coat.aspx just need to find something similar in a US vendor. For those liking some color bling- you should checkout the carbon fabrics with colored kevlar. There is now also metalized glass- which looks like platinum by Hexcel.
I have put this on hold with needing to do some more pressing maintence on the ole' truck.