https://goo.gl/images/cnkz9W

 

 

My guess is that Jaguar wouldn't offer factory tunes that they believe will cause them problems (both warranty and press). It has been said many times that JLR tested the AJ133 to 700 - 800 hp and the inference is that is the maximum "safe" limit. The extra 5% power that the SVR and P7 have over the R's 550 isn't much of a bump so my answer is 575 should be inherently "safe", though since the P8 has 592 then anywhere under or around 600 is unlikely to cause issues either. As far as service life, usage is more important that hp levels; an SVR driven by a moderate is likely to last longer than a V8S taken to the track every weekend. I doubt very much that the V8S and V8R will prove to have measureably different longevity.

Dave

Dave

 

They do, it's core academics for any classical engineering degree.

For our cars we have some good data points for what the OEM engineers consider safe. The first hardware-identical V8s were released at 495hp, clearly for risk mitigation. We have modern SVRs selling with 80 more HP, using a hardware-identical engine, but at a price premium sufficient to pay the OEM warranty cost of replacing a blown engine, and still bag a modest profit. Probably not a coincidence.

 

 

A bit off topic, but as a non-engineer and barely literate automotive lover, how is it Alfa pushes 505 HP from a 2.9L V6? My Ghibli put out 345 HP from a 3.0L V6, but I did not like the lag from the twin turbos at all, thus I would give up some HP to have a supercharger instead. Question is: Do turbos inherently offer greater HP potential than SCs?
Totally off topic: As soon as the Guilia comes out with a mid-powered V6 with say 350 HP, I'll be in the market. I won't buy a 4 cyl and don't need 505 HP; besides I like a sunroof in a four door sedan and the Quadrifoglio doesn't offer that as an option because it has a carbon fiber roof.

 

Its pretty obvious, though, since there are no engine hardware changes between the V8S and the SVR.

​​​​​That limits it to one variable: the software tune, minus a few carbon bits, to charge someone $60K more. God let's hope that's to cover anticipated warranty repair costs and not just pure ripoff.

 

Simple: a higher redline.

Dynos model HP as Torque X RPM/5252

Dyno HP is purely theoretical since work (mass moved some distance) is loosely modeled using RPM, which is obviously not really moving the cars mass. All you have to do to increase Dyno HP is rev the engine higher.

You can increase dyno HP with a red magic marker.

 

 

 

 

Another gross oversimplification. I own 3 vehicles with v-8 engines, and they all produce power very differently. My long stroke Tundra 5.7 engine produces tons of torque (550 ft lbs) and is super quick from 0-30 MPH, but my other cars would dust it afterwards. My M3 with a short stroke/high revving engine produces the least torque (360 max) but 600 hp, and at high RPM's really comes to life and out pulls the higher torque tundra. The F type is sort of in the middle. plenty of low end torque like the tundra, and almost as strong at high RPM's as the M3.

If you only focus on torque, you could end up like my Tundra - quick off the line, but then boring. If you obsess over HP only, you get the M3, fun, but you gotta rev it to go. Saying power is simply a mathematical equation ignores all the design parameters of an engine/vehicle design.
"Just increasing redline" is not just changing the software programming, way more to it than that. I doubt my Tundra 5.7 could rev to 8300 RPM like the M3 does without a complete redesign.

 

No that is not how a dyno works. The work being done is accelerating the dyno using wheels. Work is work.

 

Okay Stohlen, I completely overlooked the fact that turbos spin off exhaust pressure and SCs off belts or some other direct load on the engine.
One other question for you: Do products like Klotz octane booster actually contribute to performance improvement? An acquaintance swears by the stuff and says he can feel the increase in acceleration.

 

You're right a dyno doesn't use

HP=TxRPM/5252

It measures how far the car moved then orders uber eats and times that. Its that new math.

 

Increasing octane rating beyond what the engine is tuned for does not give more power. If the ECU is reducing power in some way because detonation is detected, e. g. pulling timing or reducing boost pressure, then better fuel will get you back to the rated power. Beyond that, there's no performance gain.

In California, the "good stuff" at the pump is just 91 AKI, and that's not really that good.

My last two vehicles specified premium so that's all they ever get. My previous, which I tracked carefully and did lots of data logging when I was working on open source tuning software was interesting. I couldn't log power, but I got better mileage with mid-grade than regular (which was all that was required) but no further improvement going to premium. I tried going through all three quite a few times and the results were consistent.

Back when MTBE was still in use here, with one of my motorcycles I consistently saw 10% difference in fuel economy between fuels that used MTBE as an oxygenate and those that used ethanol. I couldn't tell about power because once you have more than you can use without tragically heroic consequences, it's hard to quantify. My current version of that probably would make more power with better (96 AKI or more) fuel because it has a "race ECU" programmed by factory folks in San Marino, but the heroism/tragedy ration becomes more unfavorable with zero electronic assistance. As a friend described it some time back, "It's like dinner and dancing with Rhonda Rousey. It's as dangerous as you want to make it."

For the record, MTBE sucks at everything, in every way (corporate profits excluded, your mileage may vary, some restrictions apply).

 

Are you this thick-headed about every subject you don't understand?

Putting wrong words in other people's mouths doesn't make them wrong or you right, it just makes you look like you should be on cable news, which I'm guessing is where you learned all of this.

If there any other wisdom you'd like to spread? Should I go back to your sprintbooster confusion thread for more?

 

Is this statement not an oversimplification ?

My aim is to gain greater understanding, both for myself and others.

Could you comment on two points:

Peak cylinder pressure whether calculated peak bmep or peak imep will correspond to peak torque however that isn't the only contributing factor to 'engine stress. My understanding is engine rpm will obviously be related to piston speed and more importantly piston / reciprocating component acceleration which can be a significant contributing factor of 'engine stress'

An increase in peak torque, which typically occurs at low to mid rpm will obviously also increase power at low to mid rpm.

What increases peak power in all cases where the rpm of peak power is unchanged is maintenance of high torque (with high bmep)to higher rpm or to be more accurate usually a reduction in the rate of decrease of torque at higher rpm.

All things being equal, which they aren't, if our goal is higher maximum speed we need more horsepower.
If however we want more performance in terms of acceleration the the area under the curve is more relevant than absolute peak power figure and if anyone is doubtful about this assertion I ask you to data log the % time your F Type is operating at peak power as I can assure you it's significantly smaller than many would consider even for skill drivers including F type "ring taxi.

 

You still seem confounded and confused about what we are discussing.

Does a race clutch decrease time to distance?
Does AWD improve time to distance?
Do tires play any role?
How about driver reaction time?

It is too primative an understanding of power [work done divided by time required] to think that only what happens inside a cylinder affect how fast a car moved from a to b.

You are the only one who is hooked on something like a sprintbooster increasing engine power to reduce time-to-distance. No one else has ever suggested such a ridiculous thing.

All the OP said was that sprintbooster made his friend's jag astonishingly faster.

You should ask "how?" if you don't understand his friends experience, instead of making up your own fairytale storyline which no one cares about, but you.