Trublu01 said:
Umm, are you under age? I don't know about England, but the Mustang Dyno and Dynojet Dyno numbers thing is very, very, very old news. And on a Dynojet 03/04 Cobra's have seen over 380RWHP SAE. Therefore the 03/04 Cobra was/is an underrated car when speaking of HP!
That's my point EXACTLY.
If comparing to manufacters numbers to rolling road dyno numbers. A Dynojet gives a HIGHER figure which distorts the figures for comparatives sake.
Lets assume that the 380rwhp you mention on a
Dynojet has been accuratley corrected to SAE (also as you mention) and with all other correction factors considered.
HOWEVER - A Dynojet is not a load bearing dyno. So to give a more 'real world' number we need to make an adjustment to account for a load bearing dyno. It is likely to be minus about 20 - 30rwhp. If there are then any high dyno numbers it is most likely to how the operatir has the machine setup. As graph smoothing and correcting can easily show 10-15rwhp to high a number.
Regardless, all the results I have seen, if you add REALISTIC correction factors and drivetrain losses you will generally end up with estimated engine outputs of 389-405bhp type of range. Which would sound about bang on to account for manufacturing tolorancies.
I DO NOT doubt for a second that some 03/4 Cobra's produce more BHP than rated. But that is because it would be good practice for Ford to quote the minimal you should expect and not the maximum. Espcially in light of what happened with Cobra's past. However the claims of 440-450bhp STOCK I feel are optomistic at best.
That aside, the Cobra looks fantastic and sure is one darn fast car that responds really well to mods.
Oh and BTW - this all applies to the Fbody as well. It is reasonaly accepted that the LS1 is underatted, which has been verified by independant test putting a crate LS1 onto an engine dyno.
However there are NO stock LS1's that dyno 320-330rwhp. Sure there are people with graphs that show this, but that doesn't prove anything as without ALL the correction calculations being applied and being tested on a load bearing dyno to SAE standards the numbers will not be comparable to manufacture claims.
To show how easy it can be. Stock crate LS1 (direct replacement for an Fbody) is rated by GM @ 320bhp SAE Net. Although 98-00 cars should only have 305bhp SAE Net. So here's one descrepancy.
Chuck that STOCK crate engine onto an engine dyno. With an electric water pump, no anciallry devices and a set of long tube headers. It produced 429bhp STD.
Has it really gained 110bhp just by adding headers and removing the alternator and power steering pump?
No - what you would need to do is adjust for SAE standards. So having all the anciallary devices attached, plus normal headers and what ever else the standard requires. All this plus the additional correction which is probably needed to counter the different types of dyno used (engine dyno's also vary like chassis dyno's do). And you'd find that the number would probably drop by about 80bhp or so. Giving a total much nearer to 340-350bhp SAE Net, which is right where would be expected as that is what a C5 Corvette has SAE Net.
Following along this line of thought it also highlights how FEW of the 60's and early 70's muscle cars where actually producing those headline numbers. As they where all rated as a gross figure. Which as we can see made a REAL world difference of about 70-80bhp on a LS1.
So a 1960's car claiming 350bhp Gross is probably producing nearer 270bhp if it was rated today using the current system.
It all highlights just how inaccurate DYNO and ENGINE bhp numbers can be, and also how mis-leading they are.
If someone can show me (this I would really lkike to see) an un-biased test of a STOCK 03/4 Cobra engine on an ENGINE dyno being tested to FULL SAE Net standards producing 440-450bhp SAE Net then I will happily believe it and eat humble
pie. But until then...