Its interesting that the tuner group (ECU) and I also know of one tuner in the UK, that both say Jaguar horsepower claims are overstated... most of the time; or otherwise, the cars make less horsepower than claimed, consistently.
If Jaguar still monitors this forum, I would think they would be concerned that this sort of 'story' could do damage to their reputation. They are managing quality improvements now and it would be unfortunate to have this issue come up... as well, I paid for 550 h.p. when I bought the R, not something less.
Its my understanding that BMW for instance, often go the other way, which is that they understate h.p. claims and their cars often make more, but not less.
Anyway, I obviously have not seen actually engine tests to verify these claims, however, if some auto magazine every went to the trouble to dyno test a number of cars it would become clear.
Lawrence

 

I think it was Vic55 that did a dyno pull and got 447 rwhp for the R coupe. I don't see the drive train using 103hp to operate. One of the primary "features", if you will that people decide to purchase a particular car is how much horsepower it has so to overrate the car's power is bad business.

 

Companies get in to a lot of trouble if they misstate specifications. Look at the trouble Ford and Hyundai got into for overstating MPG. While there will always be engine variances, I just don't see that it's likely that a manufacturer would deliberately under or over state a key specification. The US in particular is too litigious and there are too many attorneys with the ability to generate a fast buck for that to happen. If these engines don't make close to their rated power they would be open to all kinds of litigation.

 

Certainly agree with the issue of lawyers - litigious society. Its getting more that way here as well.
The UK tuning company was 'Viezu' and they stated something similar to what 'ECU' claimed regarding overstated h.p., which certainly caught my attention as I didn't believe these comments could be written off as a marketing ploy?
Anyway, I love the car and its speed.. so the issue is more around does Jaguar not test the h.p. output on these engines on some sort of a consistent basis. And if the lower h.p. claims are true, then the company would be leaving itself open to ridicule.
Perhaps other auto manufacturers are inconsistent as well, I hadn't even thought of it in the past as it seemed a risky practice to me.
Doubt I will do a 'tune' on my car, but if I ever do I will dyno the car to see what the base h.p. actually is. I assume it would need to be 470 rear wheel anyway, to reach brake of 550. The F-type R and the XKR-S are both rated at 550.
Maybe other members with this engine have already had this procedure carried out and it would interesting to know the findings.
Lawrence

 

It looks like Jaguar is using the same engine for both the v-8s and the r. It explains why Motortrend shows similar acceleration number and trap speed despite the coupe claimed more horse power and less weight.
This video also shows the dyno number of 447 and 405.
Here’s the v8s convertible:
And here’s the R coupe:

 

Yes that was me; I do know that the dyno I used is not the strongest when it comes to numbers (I have dyno'd many of my cars there in the past) and that my car on the street has been strong. Who knows how much power is lost with the ZF tranny...

 

Why not ask these 'experts' to put their money where their mouth is. They must have done some sort of testing to make such a claim. Right?

 

I think the best test, which is not practical, would be to dyno test the engines directly.
Lawrence.

 

FWIW, 10-12 years ago Ford got into hot water with horsepower ratings on their Mustang GT V8s. Apparently the power was so far off the 'advertised' rating that the problem just couldn't be ignored. It turned out (as I recall) that a whole slew of engines were assembled with the wrong camshaft or something like that. Ford recalled thousands of 'em.

Also just FWIW it seems like it was about the same time that the SAE (or maybe ISO?) came up with a newer, better rating system. It was a voluntary thing for manufacturers. Chevy came on board with the 505 HP Z06 Corvette. Not sure who else.

Ramble switch 'off'

Cheers
DD

 

Horsepower sounds about right for the 1/4 mile times/speed relative to other cars. I do think Jaguar mislead with the curb weight. The stated curb weight of ~3600 must be on a bare bone stock car. Accessories/options always add weight, but somehow with the F-Type it adds 300+ lbs. Basically a 4,000 lb car with 550.

 

Has anyone actually weighed their cars...?

 

Every test I've seen puts it at 3,900+ pounds as tested (Edmunds, C&D, etc.). When viewed as a 4,000 pound car, the times look right. It'd be slow for a 3,600 pound car with 550 HP.

 

So where are these experts getting their numbers?

 

thin air.

 

With a manual transmission, the gear you use to take the reading will have a significant effect on the numbers you get.

 

They dyno test the rear wheel h.p. and then apply a factor for engine H.P. which they say, shows that Jaguar is often light on actual vrs. stated H.P.. apparently others, such as BMW tend to be accurate?
Regardless, I saw previous comments from ECU stating this lower H.P. and when I contacted Viezu to ask questions about a tune and then asked them to comment on Jaguar H.P... they stated the same thing, so I thought it might actually be true.
I guess if other members have the cars dyno tested, we will see what comes out. I'm likely not going to at this point.
Lawrence

 

I've asked the 4 different F Type tuners, (ECU Tuning, Eurocharged, RSC, Viezu) some very simply questions.

1. Can you send me a before and after dyno of a V8S tune that you installed?
Answer: Sorry we don't have any.

2. Can you give me a list of V8S customers that have your tune for reference?
Answer: No, we keep out customer list confidential.

3. Question to ECU tuning: You state that 95% of your customer base are dealerships. Can you give me a list of the top 5 dealerships so I can discuss with them any problems or issues they have had with the tune?
Answer: No

4. Can you show me a dyno chart of the AFR through the RPM range with your tune?
Answer: No, we don't have any.

So basically you have multiple tuners that are saying their tunes are good for XX%HP/XX%TQ gains without any actual documentation to back up that claim and that they have many happy customers, whom will remain anonymous other than one or two that post to this forum. They can't document what the AFR is throughout the RPM range even though that is highly critical in a boosted engine. Especially after the addition of a smaller pulley.

So please, buy our tune because you will be happy with it and we have not had any customers complain.

Walt

 

I have followed your ongoing interrogation of the various claims with some fascination, and share your frustration over the poor responses.

Smoke and Mirrors sales tactics.
Cannot fathom why a single one of these tuners would not dyno BEFORE as well as AFTER so they can clearly demonstrate the net change before and after results through documentation.

 

It is very frustrating because I know what a good tune can do to a boosted engine. I have tunes on both of my Turbo Porsche's and it really can make a big difference.
In the Porsche world the many tuners I have dealt with have before and after dynos on multiple cars as well as lots AFR charts. No question as to what they were selling and the performance associated with it.

I know there are a lot of potential customers that will not move until the proper documentation is available. You would think that alone would get these tuners moving on this.

Walt

 

I'm new to the tuner world but I do love how APR presents their ECU tunes. Nice graphs showing before and after, total peak gains as well as comparing different grades of fuel. 91, 93, 100.

Comprehensible dyno sheets should be the very first piece of marketing material provided by any tuner IMO.