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Re: 1.25 ratio rockers

Posted: Wed Jun 19, 2013 8:33 am
by advinnie
Hi there strange you should say that. Thats the same thing the vw garage just said so I now have a 4 into 1 header and waiting for a turbo trip exhaust silence to turn up. The garage told me that the 2 tip gt exhaust is more restricted than the stock exhaust

Re: 1.25 ratio rockers

Posted: Wed Jun 19, 2013 12:34 pm
by Marc
More information is needed there, EMPI sells two different Type I exhaust systems as "2-tip GT". I'll admit that I blew right over that in the original post, subconsciously visualizing the 4-tip ("Pacesetter") style - I had one of those on a 1600DP with 34ICTs for a while, and although it wasn't as good as a 4-into-1 it was adequate for that engine and certainly better than a stock muffler - other than the lousy clearance to both body and ground and the unpleasant sound ;)

Re: 1.25 ratio rockers

Posted: Wed Jun 19, 2013 1:33 pm
by advinnie
ImageHi there the exhaust is just call a 2 tip gt style exhaust. It can be found on vwheritage and the number for it is
AC2513418 its not a empi exhaust

Re: 1.25 ratio rockers

Posted: Wed Jun 19, 2013 2:38 pm
by Marc
Might not have been branded as EMPI where you purchased it, but all the Chinese stuff is incestuously copied amongst the manufacturers as well as the importers/retailers.
Image

Of the two, I believe that one is the better - at least it has sort of a 4-into-1 collector and a nod towards equal-length pipes. From what I've read, this is the one with the deserved bad reputation:
Image


But regardless, a true 4-into-1, even a "street" system, will be an improvement if the muffler chosen isn't restrictive. Generally, those merchandised as "turbo" are OK.

Re: 1.25 ratio rockers

Posted: Wed Jun 19, 2013 2:53 pm
by advinnie
Glade you said that cause a turbo trip is what ive ordered

Re: 1.25 ratio rockers

Posted: Wed Jun 19, 2013 3:14 pm
by Marc
If that's the Bugpack "Hideaway" style I think you'll like it. Kind of a pain to have to remove it to adjust valves (you may want to improve upon the mounting bracketry that it comes with to make that easier). The "shipping" paint is going to burn right off and rust will ensue, so be prepared to repaint it with some good hi-heat or ceramic paint before fall.

Re: 1.25 ratio rockers

Posted: Wed Jun 19, 2013 3:32 pm
by advinnie
Will do thanks for the tip

what engine combination do I need

Posted: Wed Jul 10, 2013 2:16 pm
by advinnie
Hi all I have just got a new dual relief engine case with crank but I need some advice on cam heads and carbs. Im looking at a engle 100 cam and the engine will be a 1600 twin port but im not sure on what twin carbs to use and what heads (valve size) to get. I all ready have a 4 into 1 header and a turbo trip exhaust. Cheers all

Re: 1.25 ratio rockers

Posted: Thu Oct 10, 2013 5:05 pm
by vocho1998
Hi I just read what FJCamper did post, and that's what happens to my car, I got a balance 69mm crank light, valves 42X37, ported just a Little bit, and a C25 cam. stock carb. and boy it realy runs strong, but when it hits 3000 in fourth gear, it loses it's magic. man I really have to do some adjustments,, thanks FJCamper

Re: 1.25 ratio rockers

Posted: Thu Oct 10, 2013 6:33 pm
by helowrench
vocho1998 wrote:Hi I just read what FJCamper did post, and that's what happens to my car, I got a balance 69mm crank light, valves 42X37, ported just a Little bit, and a C25 cam. stock carb. and boy it realy runs strong, but when it hits 3000 in fourth gear, it loses it's magic. man I really have to do some adjustments,, thanks FJCamper
What size pistons?

Re: 1.25 ratio rockers

Posted: Fri Oct 11, 2013 2:51 am
by Marc
Ummm...how much "magic" could a piss-poor combo like this have in the first place? The heads and cam are begging for a minimum of twice the carburetion, even if it's a 1600. About the largest displacement that you can expect to run happily with a 34PICT-3 would be 1775cc. We had one of those around here a few years back that my son was running with dual 44IDFs. It was relatively mild, but had the goods (CW crank, dual valvesprings, solid rockers, etc.) to rev out to 6500 or so. It ended up in my daily driver, and it wasn't long before I yanked the IDFs and put on some 34ICTs to get better mileage. I estimate that it lost a good twenty HP, and was running out of breath before 4500. That was with a cam similar to a W-110 (a bit more lift, 106° L.C.) and stock-valve heads with mini-D ports - with better heads the difference would've been even more dramatic. You've got a smaller cam which should be working at 3000 RPM, but the flow velocity through those heads is probably not too good - again, what's the displacement?
What kind of aircleaner are you running? If it's some low-profile chrome jobbie, toss it as far as you can or use a piece of downspout tube or something to jack it up 3-4" above the carb. You're probably getting some major "standoff" fog with a single carb atop that intake tract, and a low-profile aircleaner disrupts it which messes with the mixture.
What distributor are you using? Describe your timing procedure, provide all the details you can. If it has vacuum advance, how do you have it plumbed?

Re: 1.25 ratio rockers

Posted: Fri Oct 11, 2013 3:35 am
by advinnie
Hi all just to up date every one on what I did to my engine. I kept it as a 1600cc but changed the cam to a gene berg 307 and fitted 1.4 ratio rockers witch it equal roughly to an engle 100 cam with 1.25 ratio rockers and fitted the 4 into 1 manifold and hideaway exhaust and boy what an improvement. The bug can now hit 60 mph in just under ten seconds yes I know its not super fast but its a step in the right direction and thats still using the stock crank and stock heads which one of them has a leaky inlet valve and dual empi 34 carburetors. The engine can rev to 5500rpm but ive only done it once do to the fact im still using the stock crank and the beetle can hit 90 mph but that was fucking scary believe me. Im now thinking do I build a bigger cc engine or just fit a c/w crank and some dual twin choke carburettors? And some better heads?

Re: 1.25 ratio rockers

Posted: Sat Sep 23, 2017 5:44 am
by petew
Right, so I know this is a zombie thread, but...

Got some AA 1:25 ratio rockers in the shed. Wanna put em my turbo 1600 that already has single HD springs and a TCS10 cam. What length should the pushrods be?

Re: 1.25 ratio rockers

Posted: Sat Sep 23, 2017 10:14 pm
by Marc
Long enough that at ~50% valve lift, the adjusting screw is parallel to the valve stem.

Seriously, there are far too many variables at work for anyone to provide a pat answer.

They include the distance from cam centerline to rockershaft centerline (affected by case deck dimension, cylinder length/spacers, depth of head flycut, etc.), installed height of the valves, base circle of the cam, length of the follower from cam-contact plane to pushrod cup... this is why they make adjustable-length "test" pushrods which you can use to find the ideal length for your particular combination.

Re: 1.25 ratio rockers

Posted: Sun Sep 24, 2017 1:31 am
by petew
K, fair enough.

I assume just throwing the stock ones back in there is not ideal if I have a set of Manton Crmo pushrods already?