As I work for GM, I thought it may be a plan to let them know about the missing no 2. They changed it PDQ, I'm impressed (it normally takes an age to get anything done!).
Anyway, I've not had a chance to get near the exhaust cam, lifters and head to measure the degrees when the exhaust valve...
I'm with you.
The concecutively fired cylinders are separated by a minimum 70 cm (roughly) of intake tract at low rpm, this changes at 3.5k rpm.
The cranks a weird thing, the journals for the opposite cylinders are slightly offset relative to each other. I'll see if I can find a photo of it...
It's also in the Haynes manual for the Vauxhall Omega (the only one which covers that engine), and in a Vauxhall mechanics 'watch us build a V6' training video I've got.
Out of curiosity, why do you think it is wrong?
Really, the firing order is correct! Here's a link to the engine on GM's site! http://media.gm.com/division/powertrain/products/engine/carengines/04_car_engine_specs.html#l81
Thanks for the methodology for working out exhaust valve opening degrees, I'll figure out a way of doing that tonight...
Greg,
The firing order's great, it makes it hard to mess up when wiring the ECU in :)
Pat,
With regard to primary lengths, if I plug the numbers in for a 3 cylinder engine, it comes out with lengths of around 42". For a 6 cylinder, then it comes out as 24" (these are for maximum...
The sizes I'd earmarked were 1.75" primaries, 2.25" secondaries, and a 3" main system, as they felt (Highly scientific measurement) about right. Having just done some quick area calculations, they seem to fit the bill ok, the 3" main system is a little too big, being 85%...
Hi Pat,
6 - 2 - 1 sounds fine. I don't need to crossover (firing order is 1-2-3-4-5-6, banks are 1,3,5 and 2,4,6), so I can easily build manifolds in that configuration. I'm keen to keep the noise down to a level which'll let me run on most trackdays (98db ish).
I put together a spreadsheet...
Hi,
I'm in the process of transplanting a 3.0L V6 GM engine into an Opel Manta. I'm going to replace the cast headers with tubular manifolds, and build a full new exhaust system to suit. The main stumbling block is finding information specific to 6 cylinder engine manifold design. I've tried to...
Hi Gents,
I've been looking at exhaust manifold design, specifically for V6 engines.
All the formula stuff seems to be generic for engines with pulses separated by 180 degrees of the crankshaft. which is cool for 4 cylinders and v8's, but not for V6's.
Is it right to assume that the primary...
