16v205 9 Posted June 15, 2006 Hi Ill be fitting a gti-6 engine in the next few weeks that ive had in the garage for 12 months. Just ordered a pair of catcams, valve springs and retainers from QEP, already got the throttle bodies, and mapping is booked for 25th July so it might be a bit of a rush job depending on work Problem is im a little undecided what to use as the exhaust manifold. I dont know which one to fit, either keep the bendy banana looking gti-6 manifold or use the longmans 4-2-1 manifold thats on my mi16 at the minute? I dont mind 'manipulating' the car slightly to make either manifold fit. Does anyone know which one is supposed to be the better? Cheers Rich Share this post Link to post Share on other sites
Anthony 1,003 Posted June 15, 2006 Don't think the Longman one will fit the '6 engine will it, atleast not without modification? The bolt pattern is different to the Mi16 and S16 (which the Longman manifold will fit) and the manifold will foul the bulkhead unless you "pursuade" it with something suitably unsubtle... Share this post Link to post Share on other sites
Sam 4 Posted June 15, 2006 The S16 has the same stud pattern but the port shape differs afaik. Basically the Mi exhaust is 9 stud, GTI6 and S16 are 10 stud but all have different ports IIRC. Share this post Link to post Share on other sites
16v205 9 Posted June 15, 2006 I saw the stud pattern was similar but im yet to try the longmans on the gti-6 engine as its still on my car. The 4-2-1 has been drilled for 9 stud and 10 stud fixments. Im confident it will bolt up to the head assuming the gap between the 2 rows of studs is the same as a mi16. Are the ports on the gti-6 head that much of a different shape or size to a 1.9 mi16? Ill have to dig the engine out and take some measurements. Cheers Rich Share this post Link to post Share on other sites
Alan_M 66 1 Cars Posted June 15, 2006 I've got the same issue, but on what head to use on my new engine project. Would love to use the GTi6 head but means I would have to use the 6 manifold, which after shelling out on an X-Sport manifold and matching 2 1/2" system I don't particularly want to get rid off. The 6 exhaust ports are taller the Mi16's, and this is where you will need to mod the 4-2-1 manifold. That is if its possible to remove that much material. Certainly can't on mine! Width ways they are fine. The studs all match up too. So, looks like i'm sticking with the Mi head and 4-2-1 manifold. I suppose the spec of engine I am chasing would certainly find the std GTi downpipe that you would need to use with the 6 exhaust manifold strangling anyway. Share this post Link to post Share on other sites
petert 587 Posted June 15, 2006 (edited) GTi6 and S16 have slightly different stud patterns. One stud is different on the GTi6. Ports are completely different. There's a good pic. in this thread: http://forum.205gtidrivers.com/index.php?showtopic=60152 Edited June 15, 2006 by petert Share this post Link to post Share on other sites
Garry 1 Posted June 16, 2006 For what its worth the 6 manifold is very good. I have a 4 into 1 Pug Performance manifold (not equal length) and have lost 8 lb/ft. I would say fit the 6 manifold and sell the 4-2-1 to an MI owner. Share this post Link to post Share on other sites
jochem 0 Posted June 17, 2006 I think you cant really improve on the standard gti6 mannifold. And it looks the part too ;-) Share this post Link to post Share on other sites
16v205 9 Posted June 17, 2006 Cheers for the replys, looks like ill keep the original manifold on then. It looks like it could be a snug fit between the bulkhead? I guess it must fit though as theres a few people running gti-6 engines? Does anyone know if you have to 'shape' the bulkhead to give clearance? Rich Share this post Link to post Share on other sites
James_R 3 Posted July 16, 2006 I'm having similar thoughts at the moment, is there a larger downpipe that can be used with the 6's manifold, or will a std arvin type be up to around 200BHP of exhusts flow without getting too restricitve? Also on the system, is a Grp N ok or would a GRP A be essential? Share this post Link to post Share on other sites
petert 587 Posted July 17, 2006 I'm having similar thoughts at the moment, is there a larger downpipe that can be used with the 6's manifold, or will a std arvin type be up to around 200BHP of exhusts flow without getting too restricitve? You will need either an S16 or 2L Mi16 downpipe, or of course GTi6. I'd use the Gp N unless you have a 250hp monster. Share this post Link to post Share on other sites
jochem 0 Posted July 17, 2006 (edited) I'd advise 60mm as a minimum diameter in you exhaust line, since it is a 2l. engine. I found there was a slight difference between grpN and my current 60mm pipe. Plus these engines seem to break lesser exhaust types. Edited July 17, 2006 by jochem Share this post Link to post Share on other sites
Miles 331 1 Cars Posted July 17, 2006 I'd go along with that, The Gp'N' system is smaller than the std system on the car mainly I think as it was designed for the early cars which ran a small Dia system Share this post Link to post Share on other sites
James_R 3 Posted July 17, 2006 Ok so the 205 GTi down pipe is no good then. Thanks for the info Share this post Link to post Share on other sites
petert 587 Posted July 17, 2006 I'd advise 60mm as a minimum diameter in you exhaust line, since it is a 2l. engine. That's almost 2.5"! You're right, it is only a 2L. Why go so big? I know the 2L downpipe is 2.5" but I wouldn't make the whole system that big. Share this post Link to post Share on other sites
