Dunno yet; was halfway through a tank when I fitted it, and am less than a quarter of the way through the current tankful. The tankful that included half with this set-up was a fairly poor 44mpg, but I'm sure the snow and associated slow-moving traffic didn't help that, as well as 'playing' a bit with the new set-up to see whether I could feel any breathing differences. The current tankful will last me a couple more weeks, I'll be sure to post an update then. Had a look on vagcat, but can't see whether it might be about the right size to fit over the carb or not. One thing that looks sub-optimal is the breather being right over the carb. I guess the SPI injection unit would be much less troubled by oil mist falling straight at it than a carb with all its airjets 'n' stuff. Dunno. Would be much neater if it could be made to work, but I'm not really bothered about looks.
I picked up the SPI bits from the scrappy earlier, on first inspection it looks like it needs to be fiddled with a bit to fit under the scuttle and you need to move the Servo. I need an airbox or filter to finish it off, the GTD one looks like the best bet.
Move the servo? Fook that. I can't quite decipher the above posts relating to the GTD airbox to know if it has a warm air feed (I think not, looking at Vagcat). If it doesn't, I'd avoid using it for a carb application, personally. When you realise that the mixer flap is vac operated, so will revert to cold air only, shortly after WOT is applied, I can't see the sense in not having the temperature control most of the time.
My warm air flap hasn't ever worked and I've not really had icing problems this year, for a laugh I got a cone filter (huge bugger too) earlier for nothing and I'll adapt the piping from the SPI airbox to go to the OEM Mk2 airbox and then go from there. Had a cut airbox all winter so I don't see new problems occuring now.
Back to standard now. No appreciable difference in mpg, or anything else. Mildly disappointed. Had to be tried.
the only advantage i can see in a spi air box is that the air passage doesn't sit directly above the hot engine. but why work hard, if mk2's already had this setup in RP engines? 90% of the work is done, and adopting the flange to the carb doesn't seem too difficult.
Trying to get noticeable power gains from the low compression 1595cc by airbox mods is always going to be an ask. The manuals state the comp ratio of the engine is 9 : 1 but this is incorrect. The true figure is around 8.2 : 1. I have volume checked several 1595cc engines with a burette to calculate compression ratios. They were all done several times on differing cylinders to prove that it was not just one rogue low reading. Came to within 1cc every time on all of them. As the cylinder displacement is small, it takes vast amounts of skimming to raise the compression levels to near "performance" levels.
Making 'custom' bits for cars is fun, didn't you know? I even have two parts in my car made from oak That wasn't the goal of the exercise, but I'm sure it's useful info for others.
I've been trying to get another GTD airbox seing as i sold mine and need it again, haha! I've rang the dealer with part number: 191129607AK and aparently it's obselete with none in stock anywhere! anyone have any ideas? I need to know the size of the inlet to the GTD airbox so i can order my silicone tubing!! Cheers! Ry
ETKA says that part number should be available from classic parts in Germany, http://www.volkswagen-classic-parts.de/.
Thanks for that! It says they have them available for 36, just need to try and figure out how to use the site, my German is not the best! Cheers
