Root cause of LFX Peak HP

[AlternateDimensions]

Looking for insight on what is holding the LFX back in terms of peak horsepower. The LFX is rated 323hp @6800rpm. The dyno charts I have seen around here and elsewhere show that quite consistently. What are the restrictions that others have found? For example, lets say we want a LFX built dedicated to racing, pure high RPM powerband. Are they running out of steam do to the intake, heads (valve sizes/port size/integrated exhaust manifold), camshaft profile, etc.? Has anyone found out the true max rpm before the bottom end gives out (stock or otherwise), timing chain failures, or any other failures occur? Basically what I'm asking is if budget wasn't an issue, how far would you go, where would you start, and why? I.E. why cant we make xxx hp at 7xxx or 8xxx rpm?


Feel free to stop reading here, but I'm curious for a number of reasons.

1. I've long been a fan of the underdog. I grew up building big cube blower V8's and a spent way too much time as a teenager building v6 engines to show my old man it can be done. I built around 32 60degree v6 GM motors from the 2.8 through the 3400, both N/A and F/I between 2000-2006. 2007-2009 I was stuck overseas, then took a long hiatus for family/financial/ex issues, leads me to #2.

2. Fate has lead me to a great job with a lot of connections in the racing industry. A full machine shop, water jet, laser, close relationships with other shops that regularly build 3000+HP engines in the drag racing world. Also have a wonderful engineer fiancé whom is very supportive of my...hobby.

3. The LFX has become a bit of a big deal in swaps to many other makes and models, cough, cough, mazda, opening up even more of a market for performance parts.

4. Last year I bought a 2013 V6 A6, fell in love with, and currently have a 2014 I'm picking up to tear apart and build into a road racer and yes I will make a TR6060 work if I can't get my hands on a Hewland.

Thanks guys/gals.

[gringo]

A couple of things.

The throttle plate doesn't open to 100% until 4k rpms. No tune fully corrects this.

Compared to other engines that are similar, like the old Mustang N/A 3.7L, the exhaust ports are relatively small.

The stock cams, both intake and exhaust, are of short duration especially the exhaust side cams.

I think those are the biggest offenders according to MagnumForceGB.

With Mace cams and lots of tuning, he was able to make power up to 8k+ rpms.

[DSX_Camaro]

OP, if you want to try a TR6060, try a bellhousing from an ATS-V. They have the LF4 and in theory the block should be the same.

[bowtieracer]

ALTERNATE THE BIGGEST ISSUE YOU WILL FIND WITH THE LFX IS YOU RUN OUT OF FUEL WHEN YOU TRY TO MAKE BIG POWER AND BOOST. THE HIGH PRESSURE PUMP AND INJECTORS WILL ONLY WORK TO ABOUT 6OO TO 625 HORSEPOWER AND THEN YOU START TO BURN PISTONS AND LEAN OUT. I HAVE BEEN WORKING ON ADDING A SECONDARY SET OF FUEL INJECTORS TO HELP THIS PROBLEM BUT IT BECOMES A SERIOUS TUNING ISSUE WITH PIGGY BACKING A HALLTECH UNIT. I MADE 715 HP AT THE REAR WHEELS WITHOUT THE INJECTORS BUT HAD BEARING AND PISTON PROBLEMS REGULARY. WE ARE NOW GOING TO ELIMINATE THE HIGH PRESSURE PUMP AND INJECTORS AND INSTALL PORT FUEL INJECTORS THAT SHOULD HANDLE AS MUCH POWER AND BOOST THE ENGINE CAN TAKE. I HAVE HAD HEADS PORTED NEW CAMS GRINDED AND FLOWED. THE HEADS NUMBERS SHOULD SUPPORT ALMOST 850 HP WITH NO PROBLEM IF YOU CAN FUEL IT. I CAN NOT REPORT ANY OTHER FAILURES AS FAR AS CHAINS AND OTHER ENGINE PARTS ITS BEEN A FUEL PROBLEM AND NO ONE HAS CAME OUT WITH A PUMP OR INJECTORS YET SO IT AL TRIAL AND ERROR FOR NOW

[shibbs]

Originally Posted by bowtieracer

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Found Bowtie's keyboard:

[Tajefe Couple]

From djcolopi
"Overkill and Tracy Lewis Performance have developed a direct port secondary fuel setup for the LFX. This will solve the HPFP issues for all the boosted guys making over 500rwhp and for anyone that wants to run E85 with FI"
Post #380 shows the setup, never heard how it went though.
https://www.camaro5.com/forums/showt...377642&page=28

[bowtieracer]

Ha Ha key board post funny. Tracy Dennis and overkill's fuel enrichment is just nozzles with some jets with a solenoid that can only be batched fired (all 6 nozzles at once) at a certain rpm or fuel ratio. But there is no control ability thru the fuel curve its open or closed due to the solenoid. It causes lean spikes and to much fuel in non firing cylinders Arron at G.P.I and myself have tried the same system and made 700 plus hp.but it is hit or miss with no reliability or control ability(have few broken motors to prove it) We have tried adding 6 injectors and a piggy back computer with the factory high pressure injectors and pump but trying to map two fuel curves in two computers is a tuning nightmare.To simplify the tuning we are now removing the high pressure injectors and pump and installing 6 port injectors with a stand alone computer that fire in sequence so we can map the fuel curve from idle to peak rpm and have complete control of the duty cycle of injectors. Unless someone starts building high flowing injector and pump this will be one of the only ways to make big power with a twin turbo lfx

[DSX_Camaro]

Can you not run the LF4 injectors and HPFP? That's what was done on the Gretchen car, HPFP at least. Ryan at GPI even worked on it if memory serves.

[MagnumForceGB]

Why don't you ask how well that Tracy system worked and how much it damage it cost.

[Tajefe Couple]

Great explanation bowtieracer thanks! Just happened on that awhile back and didn't realize it was just dumping fuel. Guess assumed each injector was firing on demand. Proof why I don't like or usually make assumptions. Looks like I am the ass this time. Curious how your system turns out though hopefully you keep us posted. GL sounds like your getting close.

[Tajefe Couple]

Originally Posted by MagnumForceGB

Why don't you ask how well that Tracy system worked and how much it damage it cost.

Yea, I haven't tried to talk to that group in sometime. Think I offended them. Must have asked the wrong question about who was involved with the new/only supercharger kit on the market when it was transitioning from KPE to the current group. Definitely take your and several others word for it though.

Unfortunately haven't found any options for FI at this point. I have just enough knowledge to be dangerous and nobody around here familiar enough with these engines that I'm aware. Had some offers to be the learning curve for a couple shops though. Appreciated but took a hard pass, to many horror stories about people who went that route!

Really like to put something like the supercharger you had on yours. Don't have the desire to push anything to its limits just for increased reliable power from a V6. Like many others have done the V8 thing a few times. Thought it'd be fun to play with the V6 for a change. Oh well cars still fun even if I can't drive anymore(health reasons). Grand-kids will enjoy someday maybe!

[willoverkill]

Originally Posted by bowtieracer

Ha Ha key board post funny. Tracy Dennis and overkill's fuel enrichment is just nozzles with some jets with a solenoid that can only be batched fired (all 6 nozzles at once) at a certain rpm or fuel ratio.

It's for water/methanol injection and was used with an Alky Control controller. No issues in doing this versus doing the same thing pre-throttle body injection that this was meant to replace. If you wanted to run it with fuel and become a primary source of the engine's fueling, there's hardware to do this, but haven't looked into the external controller required to run 6 fuel injectors.

[bill522]

Will Rishworth and Tracy Lewis have been working with me (for over 2 years) to get my cars HP safely improved. Havent blown my motor or transmission up, not everyone on this forum can say the same, only pointing out posted facts. Started out at 410hp and am well over 500 with some improvements still planned. Novi 2200( impeller inspected, high speed bearings and seal upgrade by 928 Motorsports, Jan 2019) and Overkill SC System with direct methanol injection, 119# injectors and Overkill Fuel Cam. Will can add more info to my post if he wants to.

[MagnumForceGB]

Originally Posted by bill522

Will Rishworth and Tracy Lewis have been working with me (for over 2 years) to get my cars HP safely improved. Havent blown my motor or transmission up, not everyone on this forum can say the same, only pointing out posted facts. Started out at 410hp and am well over 500 with some improvements still planned. Novi 2200 and Overkill SC System with direct methanol injection, 119# injectors and Overkill Fuel Cam. Will can add more info to my post if he wants to.

Can you post a picture of your supercharger inlet? The actual blades.