Thanks, Stuart. One correction, if I may- according to his post, the car already had the upper pulley and associated tune during that baseline 490WHP run, or at least that's how I'm reading it. Add the headers, exhaust and another tune to account for the full exhaust, and his number goes up 70 HP. I don't consider the new tune to be "in addition to," because an increase airflow/reduction in pumping losses = more fuel required, period; otherwise the hard parts are useless. Granted, I'm not seeing any dyno sheets there so who knows... maybe he lost power. Maybe he's making over 800. Dunno.

Back to the headers themselves and VAP's findings- what was the configuration of your test bed car? I saw up above that it was an F-Type, but was it completely stock, or not? Did you measure any differences in pre-cat EGTs? Any changes in IAT2 and/or aftercooler coolant temps? Did boost pressure change? I would tend to think that if nothing else, ditching those 1950's style OEM exhaust manifolds would lower temps a bit.

 

Perhaps it's a little ambiguous, but I don't see anything in their post mentioning a tune. I thought it just stated a pulley 'before'. One might presume it was tuned, but we hear about people fitting pulleys all the time, thinking it will make more power and not realizing it will be venting excess boost. The way I read it, that's basically a 'stock' car for a baseline dyno.

We tested a stock FType, and then with full header system (so manifold back to center section.) And before & after with a tune added as well. On the V6 as well as the V8. At that time, we had not yet developed our datalogging system, and stuff like HP Tuners is not really that useful for generating logs. It's just not fast or detailed enough. We did manually log boost on a gauge, and did not see any change.

 

Granted the 4.3/4.7 AM has the same sized exhaust ports and stud pattern as the Jag 4.2 would you reconsider a header system for our cars

 

How much interest is there?

At what price point would people be interested?

 

There's 2 other custom builders who've successfully made true long tube headers with increased performance for both the 4.2 and 5 litre cars. Being long tubes, these did require the elimination of the CATs, which for some may be an emissions issue. Also fitment was quite difficult with such a tightly packed engine bay.

 

There's a xfr 5.0 that look to be Supersprint headers and I know Paddy Dunne had headers made up for 4.2 x100 Ive been in contact with him recently.

I'm also waiting for a aluminium f type subframe cradle to come up for a decent price however that's topic for another thread 😃😃