Hello!

I have searched for information on the internet and asked several companies, but not much seems to be available on this topic.

I have a 958 turbo project and when we have reached 750 hp limit I have begun to doubt whether there is enough fuel system capacity beyond that. The goal is at least 800hp / 1000Nm. The fuel system may run out of capacity. Injectors or high pressure fuel pump, especially if in the future also e85 conversion. Do you guys have any information on how these parts could be upgraded in this DFI engine?

 

Are you still just running the stock fuel system? Stock pumps, stock injectors? I would look into the Walbro 525/535 or something from DW, AEM, or Aeromotive for pumps. As for injectors, that's where I'm lost too. I reached out to Injector Dynamics once who told me they don't offer anything for our DI engines. Maybe some other company does? I am an idiot, but I don't see how much different injectors can really vary between engines and manufacturers... I just feel it has to be possible that there's something that fits out there.

 

Thanks for the answer! Currently I'm running the stock fuel system. Increasing the fuel pressure can slightly compensate for the increased power, but with ethanol it may not be enough.

This is a high pressure fuel system, direct fuel injection, so a Walbro or similar replacement pump is not suitable.

I know there are upgraded high pressure fuel pumps for heavily tuned BMW cars but i haven't found anything similar for Cayenne/Panamera.

 

I’m planning a similar upgrade and trying to address any limitations while the engine is out. Does anyone have any experience with stock injectors being capable of delivering 800HP?

 

This question is also being asked over on Reenlist and the answers (or non-answers) are the same: there is no answer lol. No one has done any high power builds with the 958 apparently. None that have any build threads like J'sWorld's 955 or RennMan's 957. My only suggestion would be to start calling major companies like APR or whatever, people that do rich people high power German cars and ask them for a suggestion. There has to be a solution somehow, somewhere....

 

Thanks for the reply, I’ve done a lot of research on forums and emailed many of the high performance companies and can’t find anyone with experience going next level. I can source the hardware (FVD intercoolers, pureturbos turbo upgrade, cargraphic primary cat pipes) but no one seems experienced in the tune and therefore what other changes will be required to make high HP. Btw I’ve done cold air, diverters, secondary cat back exhaust and EVOMSit tune) ….

 

So you already have an EVMOS tune. And did you try talking to EVMOS about your situation with higher horsepower goals and fueling concerns? You'd think they or someone they know would be able to point you in the right direction. That's too bad, because their tunes are NOT cheap. You'd think they'd come with a bit more "service after the fact" if you will. If I'm paying $3200 for a one-time map flash of my ECU, you damn well better be available for questions later down the road when other companies charge less than half of that for the same exact product (tune).

Did you try asking Softronic? I still need to ask them how tuning for E85 down the road might work with their software.

 

EVOMSit have been good with supporting the current hardware and tune. The only thing they could offer for the stage 3 mods is develop a tune on their Dyno using my car which isn’t practical given I’m in Australia.
I don’t think I tried softronic directly …. They don’t have anything off the shelf.
I did get some positive feedback from a local tuner that looks like a solution but won’t be able to confirm for a few days. He needs to buy the ECU tuning equipment from a German supplier but they have a tune that matches the 800HP turbo upgrade they’re offering.

 

Have you tried Todd with and/or PROMOTIVE? He/they build lots of 4 digit Porsches. I bet he'd have an answer for you. He's great and I'm working with him to tune my 958 currently. How are you tuned at the moment?

https://www.protomotive.com/wp422/product-category/cayenne9pa9pa192a9ya/tuning_cayenne/?v=7516fd43adaa

 

Softronic is trash. At least for the goals you have. He/they can't tune anything special or custom. Trust me, I tried asking him to tune my water methanol injection lol

 

This was the response to a post on Rennlist as this user also goes by Elspoon958.... Post 12. Not very knowledgably in Porsche.....

https://rennlist.com/forums/997-forum/1311102-997-engine-tuning.html#post18274183

 

Boy, Softronic sure is after me! He finds every post I say anything negative about him and has to make a stink about it. Very interesting. Once again, the Softronic guy cannot tune for water methanol whereas Promotive can and will. That's why Softronic lost my business. He either doesn't know, or doesn't care to learn how to tune for water meth or any more custom setups. Porsche and many other vehicles and platforms benefit all day long from a water meth injection kit, or nitrous, or E85 etc.

 

FWIW for anyone who might find this thread currently or in the future in search of options... I was actually looking for the driveshaft bearing upgrade options for my 958 and ran across this: [b https://www.jxbperformance.com/products/034motorsport-high-pressure-fuel-pump-piston-upgrade-kit-audi/vw/lambourghini-20tsi-25tfsi-30tfsi-40tfsi-42-fsi-50-fsi-50-tfsi-52-fsi-52-tfsi-w12]034Motorsport High-Pressure Fuel Pump Piston Upgrade Kit

and quoting them: I am skeptical because it doesn't actually specify Porsche or the 4.8 TT motor anywhere... so I don't know how or why this item came up as fitting a 958 Cayenne alongside the driveshaft bearing options this company offers lol... but hey, it might be worth looking into. I'm wondering if you upgrade the stock HPFP with something like this, alongside maybe some Walbro 455lph+ type "regular" fuel pump(s), maybe that would be good for E85, for Mr. OP.

 

​​​​​​​hey mate, did you ever find an answer to the fuel flow limits of the 958 turbo? ​​​​​​​ive also been looking for the answer to that question, and found the same thing (no one seems to know) ​​​​​​​im planning on bigger turbos, as mine are at their limit, ​​​​​​​and ill probably run a secondary fuel system (port injectors) .to support the power i want

 

I would just drill tap the intake manifold and add port injection