Have dyno graph comparison between stock manifolds and yours? That should show exactly where the power gains (and losses) are.
Just got my custom gp headers back from jet hot coating and beginning to heat shield them before install in two weeks. These are the same style as oem with slightly enlarged diameter in a much better stainless steel. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Those look great. Why did you go with larger than stock ID? And what are you using for heat shield material?
I read in previous messages on the thread the car can use a slightly bigger diameter which I got at 41mm on the primaries for better flow. The heat shields are heat products header armor. I read online these were the best aftermarket diy that lower engine compartment temps
No one using the Quicksilver rebuilding service? They use thicker, higher grade ss and explain their process here: Ferrari F355 Manifold EXCHANGE (1994-99) - QuickSilver Exhausts They reuse the mounting flange, collector and retain the CO testing ports and oem heatsheilds. $3200 usd plus shipping each way is not inexpensive. Pushes close to $4k with shipping costs. If I was not after retaining an OEM look, I suppose the cost of Tubi isn't so bad
RM, those headers look great. I am glad to see that Zack and his crew are still building them. I like your heat shielding as well. These headers are one of the best deals out there for these cars. OEM design, thicker and improved s/s and a reasonable price. You can chose what type of shields to put on them. I reused my original shields and had Zack build my headers in 321 s/s. Zack built the first set for me. I am glad to see some owners are taking advantage of this deal. By the way, what grade of s/s did you have yours built with?
Nope, used QV London way back in like 2006. QV London was one of the first (though I believe they farmed out the work). But, mine failed after about 6 year later, due to their process being cheap, they only replaced the pipe from the mounting flange on the head, to just past the first bend. So of course, they fail just past that point. I had them removed by the local dealer and sent them back and they redid them, replacing the tubing all the way to the collector like I had expected. BUT, they did not install any insulation under the heat shielding this second time, so they rattled now. The dealer was kind enough to carefully remove the shields, install some insulation and tack weld them back up at a reasonable cost. Overall I would NOT recommend QV London for this process. Quicksilver (by my estimation) appears to be doing it the correct way from the start.
The car I did them on sounded so wild. One of the best 355 I have heard. Had SECA headers, high flow cats, Capristo bypass and Level 1 Capristo it was insane.
Before I had my headers built, I had thought about having my headers redone by QV, but like F355 spider posted I don’t believe they were redoing the whole header at that time and just repairing part of the tubes. They look very nice now. At the time I did mine, I had contacted quite a few different places about fabricating them in 321 s/s and the prices were anywhere from about $5200 to $9000. Prices for Tubi’s were $7200 at that time in the US. I found Stainless Headers that were willing to build them for significantly less.
It had to to with the tubing sizes availability in the US vs s/s tubing in Europe where the sizing is metric. I can’t speak for what Zack used on RM’s heade, but if Zack used the same size as what he used on mine, than it is only slightly bigger. Nothing significant. I had spoken with one of the Ferrari shops and the person told me not to increase the tube size to 1 3/4” unless I was going to track the car.
I checked my order form and thought he has used 321ss but I checked the emails and he said he couldn't get 321 due to supply shortages so we went for the standard 304 which he said should be fine.
In 2015, I had a set made out of 321 SS and retrofitted with OEM shields to preserve OEM look. Vendor was UK-based IIRC, but got contact though Ricambi. I wonder if someone can do headers out of inconel nowadays.
