Ob917

Well guys my Google search for answers is not really working out, is there any real world 9A1 big bore knowledge somebody here can help me with?

I’m in SanDiego and did have a in person talk with the guys at Vision Racing in OC, super nice guys who build and race lots of P cars but their knowledge of 9A1 seems limited I’m sure because there just aren’t that many of these engines being built like I want. But like I said super nice and willing to help. I’m not sure of any other engine builders in the Southern California area that have experience going big with the 9A1???
I’m looking for a like new rebuild of my 3.6, street and some track duty. Limited slip diff and beefy clutch at the same time. Drive in drive out big bore type of service.

What is the most practical engine size cost per HP and drivability per dollar amount? 4.0lt up to 4.5?? It’s not easy to find much info, besides the very limited info Flat Six released about the 4.2 X motor. I’ve written those guys off at this time, they don’t seem to have the time right now to help with the 9A1. I bought their webinar which was very interesting but not the stuff I need unless I missed something. The 4.5 engine that DeMan builds is interesting but they seem to be just working on the GT4 version? Who am I missing?

Info on my car and its needs. Super developed chassis JRZ pro 3s etc etc etc, semi light weight with carbon roof etc etc etc. High mileage but running very well 3.6, slight but normal oil usage. Before I hear all the just buy a turbo 🤪I’ve spent years and years down the turbo path and I’m over turbo engine characteristics, and the turbos are built more GT. I could have bought a gt3 at this point but I’ve also had cars that are so hard and expensive to replace if something happens I get too paranoid to use those cars like I want. With a base 997 I can just buy another one and swap my parts if there is an issue, no problem. But I want more response and sharper power than a factory 3.6 or 3.8 makes.

I know long post lol. Looking for whatever you guys with ((((9A1)))))) knowledge can teach me. Thank you guys in advance I always find the people on this forum to be the best

Optionman1

I would suggest you talk to LN Engineering and see what they can offer beyond a 4.0 for a 9A1 engine.

Ob917

Those guys have great products and I’m sure I’ll be using some of them. There isn’t much info on their site regarding the possibility’s. I’ll brobably have to give them a call.

Optionman1

@lnengineering Maybe you can jump into this thread and help out with some info. Thx.

flat6fan18

As far as engine builders, Jae Lee at Mirage?

https://www.mirageintl.com/

And then there’s Neil Harvey/Performance Developments as well. Though he’s in Florida I believe

997ajk

I would check with Hartech .



911uk.com - Porsche Forum : View topic - Hartech rebuild and upgrade to 4.1 UPDATE - 1700 miles in.
Our first 9A1 Gen 2 I increased from 3.6 to 4.0 and we are now working on a 3.8 to 4.2 for that range in anticipation that eventually some will score bores and the same scenario will apply.
Porsche Engine Rebuild Prices - Hartech

I wonder if 4.0L GT4 / Spyder motor would work - it is a 9A1 configuration.

Replacement Engine 9A2-100-923-X | Porsche Parts Orlando (porschepartsdepot.com)

Sporty

Try Deman Motor sports, at least for info/feasibility in NY. They do a built 4.5 I believe in a Cayman(GT4?). Also there is a US counterpart to Hartech, I believe (Slacker Racing?), their is somebody in NC and of course FSI (Jake Raby who builds a monster 4.3s but it going to cost ya $$$)

Ob917

That’s why I mentioned both of them in my original post. But I’m not sure if the components that they use in the 4.5 GT4 conversion would work or not? I’m not an expert on those GT4 engines. I don’t know what the differences are.but I know some of you guys are experts

stephen k

Subbed. Love that you're going all the way on your 997. Still going for that same route on my side as well. Love the new blue color and I had to buy new arms since you didn't want to part with yours lol..

Interested in seeing what you end up doing. Car is not slow (although yours being a .2 and mine a .1) but 450hp and 400 tq would be near perfection.

Ob917

haha thanks man, yes 450 would be good!!

BRS-LN

Flat Six Innovations will be holding their quarterly (free) 9A1 Technical Webinar in a couple of weeks with Jake Raby. Submit a ticket at www.flat6innovations.com to be invited
Since the 18 month long LN/ FSI technical merger was completed in July things have settled down to a normal pace and FSI has began accepting 9A1 work again. The 9A1 work (and all other new work) was suspended in February of 2022 so the backlog could be worked away to facilitate the merger. The dust has cleared, and the things that we've been collectively working on are ready to be rolled out.
Lots of exciting information will be shared in the webinar, discussing what FSI has learned with the 9A1 program dating back to February of 2010 when the first 4.2L "Cayman X" was completed. The figure of 450HP was mentioned, and Cayman X was making that power in 2010. See Panorama Magazine from January 2013 (or maybe it was December 2012?) pages 66-71 for the data.
Part of the webinar touches on bigger not being better across the board, and what considerations must be made when choosing engine displacement, so power is increased across the board without compromise. Discussions concerning the SUMEbore cylinder technology that LN and FSI have developed aside from anyone else in the industry will also be discussed, and how this is now an option for the 9A1 platform, exclusively with the program. This has been a 6 year developmental project to this point, and is finally coming to fruition for production engines, being rolled out for the FSI 9A1 engines first.
@Ob917 FSI prefers to base big engines from the 3.6 variant, and have found many aspects of the 3.6 engine to be more favorable for heavier levels of modification.

Ob917

Ohhhhh this is awesome and unexpected news! Thank you for the info!

Sporty

"FSI prefers to base big engines from the 3.6 variant, and have found many aspects of the 3.6 engine to be more favorable for heavier levels of modification." Hmm this is interesting , curious as to why, thicker walls to start with ..... ?
No more "S" envy when it comes to this haha (never really had it, just kidding)

Petza914

Wonder if that 3.6 preference comment only pertains to the .2 9A1 engines or to the M96/M97 also. Might have something to do with the closed deck design of the .2, but I don't know.

BRS-LN

For starters the 3.6L base engine comes factory with a longer stroke than the 3.8L. In the very first days of 9A1 development FSI learned this, and fitted the 3.6 crank to a factory 3.4L case and coupled that to the 104mm Nickies, creating a 4.2L.
Later the FSI billet stroker crank was developed, but the early efforts up till 2012 used a factory 3.6L crank, fitted to the earlier cases with positive results.
When fitting with Nickies it doesn't;t matter what the original bore size was. With direct plating of original bores this does matter, as some cases have thinner bores than others. Some confusingly similar engine programs have learned this the hard way when a void existed in a stock cylinder after boring and this later formed a crack and failure. More of these cases are being reported, primarily because of a lack of development and testing.
The 3.6L heads also have some benefits, as the factory 3.8L heads saw some handicaps to keep the power within reason, and create a differential between the GT3 engines.
This is no different than the M9X, where the 3.6L engines also have the best ports to modify. With those engines the (early)3.6L modified (FSI) CNC ported heads can outperform even the best 3.8L "Normal S" heads as well as the 997.1 X51 heads. To date the strongest R43 @4.3L made 482HP at the crankshaft and utilized early M96.05 (997.1 base) cylinder heads. This outperformed the most recent R43 that was based from a factory 997.1 X51, using modified heads. The flow port data aligned with the power derived from each of those engines. In know that there's a whole chapter in the upcoming book (All about M9X Performance Engines) that Jake is ready to roll out.
I would have never dreamed this would be the case, but after 20 months of seeing and experiencing these differences I can testify that what the factory offered as their best and biggest is not the best to modify.
Part of what separates an engine builder from an engine assembler is understanding these strengths and weaknesses of each variant, then combining the best the factory had with the best the aftermarket has to create something even better.