Saabnut Posted February 9, 2021 Share Posted February 9, 2021 After nearly a year away being fettled, the Cobra is nearly finished and had a small road test at the weekend (it is a long way from here so the weather was not a problem). On Friday it goes to Northampton Motorsports for a tune and dyno run. This car has a 427 cu in engine fitted (7 litre) and the engine was originally a 400 cu in which in factory tune produced 185bhp. It has been bored and stroked to 427 cu in and allegedly has forged pistons and a performance camshaft, but never has been dyno tested. I estimated (judging from performance compared to my Saabs, the weight estimated at 1100kg etc that it was producing around 260bhp since I have had it. BUT during the fettling many faults were discovered, including a broken distributor clamp, the wrong firing order and set up with number 1 cylinder on the wrong bank! Good job you can trust specialists So, the question is, how many horses will it produce on the rollers on Friday? Nearest to the actual peak recorded will receive a free pint at the next AS meet we are both at, or can be collected from here at any time! I really have no more to go on than what is above but will put up my guess before Friday lunch time when it goes on the dyno. Guesses below please! Kiltox, Tepper, sutty2006 and 4 others 7 Link to comment Share on other sites More sharing options...
cort1977 Posted February 9, 2021 Share Posted February 9, 2021 420. Link to comment Share on other sites More sharing options...
loserone Posted February 9, 2021 Share Posted February 9, 2021 262BHP 2 minutes ago, cort1977 said: 420. hurr hurr Link to comment Share on other sites More sharing options...
Soundwave Posted February 9, 2021 Share Posted February 9, 2021 281. Link to comment Share on other sites More sharing options...
garethj Posted February 9, 2021 Share Posted February 9, 2021 285bhp👍 Link to comment Share on other sites More sharing options...
New POD Posted February 9, 2021 Share Posted February 9, 2021 273 BHP at 5400 RPM 295Nm at 3123 RPM And a red line at 6501 (that is don't take it above 6510 because it wasn't built by Honda. Also we need to know when the rolling road was last calibrated. Link to comment Share on other sites More sharing options...
JeeExEll Posted February 9, 2021 Share Posted February 9, 2021 348bhp (calculated @ flywheel) at 5500rpm and loads of torque across a wide range, max 370Nm. That's only about 50bhp/litre at the flywheel, same as a totally standard Pinto in a Cortina. Original mid 1970s 400ci 6.6 Firebirds, etc were strangled to fuck but took to tuning well. IIRC the Smokey & The Bandit Trans Am was a 185bhp 6.6 litre , - that's 28bhp/litre. (Often through a 3-speed slushbox too). Whatever the figures turn out to be, in a 1100kg car it'll be 'adequate' Link to comment Share on other sites More sharing options...
Talbot Posted February 9, 2021 Share Posted February 9, 2021 322 HP at 5500rpm. Also, is this wheel horsepower, or corrected for flywheel horsepower? Link to comment Share on other sites More sharing options...
DVee8 Posted February 9, 2021 Share Posted February 9, 2021 293 bhp Link to comment Share on other sites More sharing options...
HMC Posted February 9, 2021 Share Posted February 9, 2021 312 bhp Link to comment Share on other sites More sharing options...
artdjones Posted February 9, 2021 Share Posted February 9, 2021 325hp Link to comment Share on other sites More sharing options...
New POD Posted February 9, 2021 Share Posted February 9, 2021 1 hour ago, New POD said: 273 BHP at 5400 RPM 295Nm at 3123 RPM And a red line at 6501 (that is don't take it above 6510 because it wasn't built by Honda. Also we need to know when the rolling road was last calibrated. I'm assuming at fly wheel. Link to comment Share on other sites More sharing options...
Macscrooge Posted February 9, 2021 Share Posted February 9, 2021 According to information I’ve completely made up, the correct figure is in fact 299. Link to comment Share on other sites More sharing options...
puddlethumper Posted February 9, 2021 Share Posted February 9, 2021 No no no. You're all wrong. It's obviously 335. Link to comment Share on other sites More sharing options...
eddyramrod Posted February 9, 2021 Share Posted February 9, 2021 At the wheels? I'm going for 335. Link to comment Share on other sites More sharing options...
wuvvum Posted February 9, 2021 Share Posted February 9, 2021 So if it's 335 do puddlethumper and eddyramrod each get a half? stonedagain, puddlethumper, Ghosty and 1 other 2 2 Link to comment Share on other sites More sharing options...
Low Horatio gearbox Posted February 9, 2021 Share Posted February 9, 2021 283 at the wheel. (355 -380 after fettling) Link to comment Share on other sites More sharing options...
JeeExEll Posted February 9, 2021 Share Posted February 9, 2021 Is it a 3-sp auto? Am not sure how 'at the wheels' readings are converted to 'flywheel' estimations. There must be some margin for error with the calculations, based on tester's experience and the condition / efficiency of the box. Link to comment Share on other sites More sharing options...
The Moog Posted February 9, 2021 Share Posted February 9, 2021 311 Link to comment Share on other sites More sharing options...
Crackers Posted February 9, 2021 Share Posted February 9, 2021 21-02-09-15-08-07.mp4 gadgetgricey and JeeExEll 1 1 Link to comment Share on other sites More sharing options...
bunglebus Posted February 9, 2021 Share Posted February 9, 2021 196 BHP at the wheels Link to comment Share on other sites More sharing options...
Pieman Posted February 9, 2021 Share Posted February 9, 2021 269 Link to comment Share on other sites More sharing options...
captain_70s Posted February 9, 2021 Share Posted February 9, 2021 3 hours ago, Saabnut said: the engine was originally a 400 cu in which in factory tune produced 185bhp. A typo surely? Link to comment Share on other sites More sharing options...
somewhatfoolish Posted February 9, 2021 Share Posted February 9, 2021 23 minutes ago, captain_70s said: A typo surely? No, lazy detroit penny pinching, alaruming smog nonsense that was very silly and increased fuel consumption and a soupcon of insurance loadings for big horsepower meant the 1970s were the decade that power was forgotten in the US. IIRC at one point there were 5 litre small blocks available that put out something like 120 nags, makes the 90bhp V8 in the stage one landrover look like a NASCAR entry. My guess is 427* on the basis that 1 dobbin per cube is about as much as is readily achievable while remaining civilised on the road with analogue things like dizzies and carbs. *I reserve the right to retrospectively claim I meant SAE, DIN or some other made-up standard that allows me to win. Saabnut 1 Link to comment Share on other sites More sharing options...
Kiltox Posted February 9, 2021 Share Posted February 9, 2021 Hearing/seeing/smelling this fire up in a barn is definitely one of my top automotive moments of all time, as I’m sure @320touring will agree. 320touring 1 Link to comment Share on other sites More sharing options...
bezzabsa Posted February 9, 2021 Share Posted February 9, 2021 I shall state a Rolls Royce figure of "Adequate" 397 otherwise Link to comment Share on other sites More sharing options...
Saabnut Posted February 9, 2021 Author Share Posted February 9, 2021 As far as I know, it will be at the wheels. It is fitted with a manual 5 speed Tremec box, and my mechanic has suggested a self imposed rev limit of 5500 due to the large amount of reciprocating mass! Link to comment Share on other sites More sharing options...
SmokinWaffle Posted February 9, 2021 Share Posted February 9, 2021 328? ish. Who knows. Link to comment Share on other sites More sharing options...
Tickman Posted February 9, 2021 Share Posted February 9, 2021 346 Link to comment Share on other sites More sharing options...
Inspector Morose Posted February 9, 2021 Share Posted February 9, 2021 I’ll have a guess at around 370 at the wheels. Link to comment Share on other sites More sharing options...
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