Hello
Got 2017 f-type with 5.0l SC and was wondering can one just swap in a smaller upper pulley for a small torque increase without having to get a tune for car please?

 

Chris, Stuart you are in the best position to answer this.

 

You should always optimize the ECU for it. Depending on the size change it may work within the OEM margins but it's not ideal.

 

The benefits of just swapping the upper pulley will be minimal if any because the ECU controls the boost pressure with the bypass valve. You should consider an ECU remap as a first option and a pulley swap as an add on if so desired for extra power/torque. The ECU flash is $735.00 and well worth the performance boost.

 

Hi there

I have an SVR and I might tune mine in a year or two when the 575PS bores me.

Of course I've researched it a little and this is what various people and tuners told me:

- On the R the ECU limits boost to 13psi on stock map, not sure about SVR? As such just fitting a smaller upper pulley will create addition power/torque but only in the low and mid range, any top-end gain will be minimal to nothing, the boost will just reach 13psi sooner, say 4000rpm instead of 5000rpm. So on an R maybe 560PS and an SVR say 580PS
- Doing a map, no idea who is the best, but that will allow more boost than 13psi and should generally put an R in the 625-650PS area crank.
- You can also fit an overdrive crank pulley for upto another 30-40HP on top.

No idea how safe or reliable it is and am sure others can chime in but it seems people run the 5.0l SC motors quite happily in the 650-700HP region crank.

The Project 8 I believe has no hardware changes from the R or SVR engine wise and is 600PS so they got the power by improving the tune alone?

 

Yes indeed you can get the 550HP R engine to 600HP just with a tune. You can reach 650HP with a smaller supercharger pulley.

 

The only folks claiming as much as 650 hp are using 20% as a drive train loss. 15% is a more generally accepted loss. Some might claim a larger loss with AWD, but remember, on the F-Type AWD almost all of the power goes to the rear wheels unless the rear tires start to spin, which doesn't happen on the dynaPack since the hubs bolt straight to the 4 pods. We've consistently seen about 625 bhp on fully tuned AJ133s

 

15% for the RWD and 18% for the AWD are industry standard for the F-Type powertrain loss. Factors such as fuel, temperature and altitude affect the numbers as well, but 600HP fully runed is a very reasonable claim for ECU remap only.
The ZH 8HP70 is rated at =<10% loss (class leader)

 

The supercharger has an internal bypass valve inside that is set to open at 13 psi, and will bleed off any excess boost. On the stock pulleys, the car will actually generate 15psi if that valve is kept shut with ECU Tuning.

So adding the supercharger pulley will generate more boost at lower RPM, because it is overdriving the charger, but will still cap out at 13psi unless you reflash the ECU. So the peak numbers will be unchanged, it will just square up the left hand side of the torque curve.

The upper pulley will add 1.5psi of boost, adding a crank pulley will add 3.5psi.

Looking at your location I think you might have reached out to our UK dealers David Appleby Engineering regarding this, should have a similar answer there.

 

That sounds about right to me Lance. We see roughly 600-605BHP with our ECU tuning and 625BHP with the smaller supercharger pulley.

Since the 600BHP levels require 15psi of boost to achieve, and an upper pulley adds 1.5psi of boost, that's about the maximum you can get from 1.5psi addition. To get up to 650BHP levels requires the higher boost levels you get from the crank pulley. No magic pixie dust.

 

SVR still runs 13psi. I would suspect the project 8 runs 15.

 

The upper pulley achieves 650HP. The Viezu Predator has just tune and upper pulley. Let's not forget that the upper pulley diameter has a lot to do with it... That's a fact.

 

You've stated that the tune alone makes 600BHP. Can you explain how the upper pulley adds 50BHP? It's not going to be torque demand,
timing or fuelling since those are already being amended. It can only be from boost increase. The V8 upper pulley is 65mm. A 62mm Upper pulley is the smallest you can go without running a dangerous wall thickness. That pulley size will increase boost by 1.5psi.

A 60.5mm upper pulley can be fitted if the snout is shaved, will produce 2.25psi of boost. Neither of those numbers equate to 50BHP.

 

Stuart a 60.5mm pulley (I guess you did your homework on our work) can be fitted without shaving the snout on most engines, few require minor grinding of high spots. It's just not a cheap aluminum pulley. As a matter of fact Eaton strongly discourages using aluminum for the supercharger pulley due to the fact that it has greater slippage over steel (of course there are surface treatments for the pulley if one wants). The only reason to promote and sell an aluminum pulley is for easy of installation (heat and slip on) while a steel one requires the removal of the snout and pressing.

The facts are clearly verified and published, I am not going to spell out how and what we do. Anyone can Google "Viezu Predator". And yes... there is another more aggressive tune for the upper pulley swap. Stuart, I will not engage in an encore with you as I would like to keep everything civilized. The 650hp fact are all out there and verified.

 

Yes we know the size, Lance had one on his car when we helped him out with the tuning for the crank pulley. No secrets. I agree with you that aluminum is not the best choice, that's why we went with stainless steel.

Glad you want to keep things civilized. That will be nice. I'm in agreement.

 

Lance does not use one of our pulleys. I can assure you of that. His is likely from Eurotoys.
I can share that we are finalizing tests on a composite pulley to still allow for an oven and slap on installation but steel to work with thin wall and better slip prevention. A decision needed to be made, should this be a shop installed option or user installable. The in shop ones will still remain all steel.

 

That's not what I was inferring. I mean that we were aware of sizing and options. Your composite pulley sounds cool.

 

But yet you sell aluminum ones on your web site?

 

been a while since i browsed the tuner threads - have tuners sorted the issue with disappearing oe crackle/burble post reflash yet?