Just an idea to build up a database of good working setups, so others can use them as a starting point: For this to work, you'd need to give some info about the engine, the type of carbs, and then the choke and jet sizes that are in them. Include more info if you think it's relevant. I For example: Engine: 1800 KR (16v) - std with 4-branch manifold Carbs: 2 x Dellorto 40 DHLA on a long Rowland Manifold Setup: Chokes: Idles: Mains: Airs: Emulsions: Pumps: More info: - Made x BHP and y lbft on z's rolling road - Ignition 10 degrees at idle (KR ECU) - Comments: e.g. A bit flat lower down, but works very well above 3000 rpm - revs well to the limiter... etc. ...Just an idea. Hopefully folks would find it useful? Although the example is for twin carbs, it would be useful to have jet specs for an 1800 8v GTI motor on a 32/34 DMTL, for example.
Ok... here's the 1st. Slightly irrelivent to many but... Engine... 1800 8v, 13:1cr, big valve head, race cam, short primary 4-1, 2.5" Supersprint system Carbs... 48 DCO/SP Webers on a well ported Mangoletsi manifold (the common std type 8v manifold available), 65mm steel Weber trumpets. Set up... 39mm chokes 4.5 Aux vents F16 emulsion tubes 160 mains 155 air correctors 55 F8 idles 40 pumps More info... Pulls strong from 4k to the end of the rev counter, will take full throttle from 3.5k, falls flat on its face with full throttle @ 3k, but pull's fine from 1500-3k on up to 3/4 throttle... big cams, big carbs, big chokes & short 4-1's should'nt be used with full throttle at shopping speeds anyway. Made 164 atw's @ 7.5-7.9 (193hp, 148 ib/ft of torque @ 5k) Ignition @ 32 degree's @ 4.5k with std MK1 1800 GTi distributor
Here's a usefull one we did yesterday... Engine... 1800 16v KR, tsr head, 276 tsr cams, std bottom end, 4-1 Ashley manifold, Jetex twin box system. Carbs... 45 DCOE Webers (new type 152) on a JMR custom inlet manifold. 65mm steel Weber trumpets. Set up... 36mm chokes 4.5 Aux vents F16 emulsion tubes 145 mains 150 air correctors 55 F8 idles 30 pumps 3.5 psi regulated pressure More info... Make std power at the low end (no loss), pulls strong from 4k (97 v's a std engine @ 78), makes a peak of 150atw's (175-180 atf/wheel) @ 6,500 (std engine 112-114 @ 6k), holds 148 @ 7k, 147@ 7.5 Pulls very well on the road in a lightened mod-prod hillclimb MK1... 16v's "can" work on carbs, and you dont need 2ltrs to make the numbers or loose low end power. DTA mapped ignition used which does help with the overall result, a std 16v ignition wont give the same performance as above.
Engine: 1800 KR (16v), rebuilt std 027 casting head - mostly std with long primary 4-1 manifold & std diameter stainless system, fairly low milage rebuilt, compression 200psi +/- 5 across all 4 Carbs: 2 x Weber 40 DCOE (TIPO 38 & 39 I think, original Italian made, factory equipment on something old and British I was told by the old fella who tuned them) on a long Rowland Manifold (thanks Danster) Setup: Chokes: 34 Idles: 45 F8, F9 worked just as well as a starting point, F11 was a tiny bit lean and caused stuttering Mains: 140 Airs: 180 Emulsions: F16 Pumps: 40 Trumpets: the long ones (60mm I think) More info: I had it set up locally as the man was supposedly an expert in the field, unfortunately it was an ancient RR with analogue dials and no graph printout. Anyway; - (supposedly) Made 160 BHP atf and ? lbft on Peter Baldwin's rolling road @ about 6200 - Ignition: originally sans vacuum advance, can't quantify but it was about 5 degrees away from the most the dizzy would give. Recently involved the vacuum advance system as an attempt at refinement, had to use a large vacuum 'buffer' chamber and restrict the feed pipe from the manifold: as it is only tapped on one runner the pulsing vacuum had a net effect of no additional advance previously. - Comments: e.g. the odd cough from the progression circuit on cold engine, fine once warm. 2.5psi pressure from Facet Silvertop competition and Filter king regulator. Really comes alive at 3000, truly awful running when trying to pull below 1000, very rev happy. Really excellent throttle response compared to the single DMTL on the 1600 the engine replaced. The assometer reports a fairly flat torque curve between 3000 and limiter. Record max MPG circa. 34 slipstreaming lorries on a long run recently on the motorway. Record min MPG circa. 17 before jetting refinements. Average MPG circa 24, it would be less if I could afford to put my foot down more often.
Can I submit a request? Was a 1.8 8v DX originally. Now with a mild ported EX (I think) head, solid lifters, Piper 285 cam (276deg I think). Weber 40s on the short manifold. Supersprint 4-2-1 exhaust manifold going into a 2" system. When I dig the paperwork out I'll post up what was in my 16v
Thread revival! I've been playing about with jet setups today and logging AFRs, thought this might be useful/interesting info: Setup is similar to last time: DCOE 40 38/39 F16 emulsion 34mm chokes 60mm trumpets Rowlands inlet manifold 2.5" Supersprint system front to back, 4-2-1 Supersprint manifold These are the AFR plots measured on the road using an SLC PP2 AFR datalogger, filtered to give WOT results only. Although I haven't measured AFR results back to back with any standalone gas analysers, I'm under the impression that this device is about as accurate as they come without paying professional prices. These results focus on 3000 rpm onwards, as the idles are set up for stoich cruising. Air conditions were around 14deg C, 1020 hPa. 130 Mains, 175 Airs: 135 Mains, 170 Airs: Next stop is 165 airs to bring the top end down a little, I'll post that too when I've made the change
