It has been done before....

 

Yes this is correct.

Perhaps my post was not clear..

We are using a billet crank which is custom made to our specifications. So the crank shaft issue has been addressed.

And we do offer a different spec for the NA engine as well as the Turbo engine.


If you have further questions please feel free to email me directly would be more than happy to offer any other information you may need.


Fabryce@gmgracing.com


To answer some other questions:


We design the piston in house and it is custom made by Mahle Motorsport to our specification.

For the NA engines we offer a custom TI rod and the Turbo engines receive custom made forged rods.



I will try and answer everyones questions as best I can through this post but its always best to email me directly for specific answers.

 

RS Tuning 4.3 ... Holy thin cylinder walls, batman!

 

Here are few pictures of the cylinder CNC porting we offer.

Each port is digitized and they are matched exactly for maximum CFM flow.






This head is set up for our sealing ring system for the high boost applications ( turbo head shown)

 

Thanks for the clarification.....

When you say it has been "addressed" I guess you mean in its design ie it is different and strengthened compared to the higher reving lower torque GT3 version and works in theory ?
Is it safe to say it has been addressed before you have actually tested it ?

I hope it works as presented and look forward to follow your builds and results warts and all.

Why do you break in the engine on the engine dyno but power test on a chassis dyno ? this doesn't make sense, all serious race teams and manufacturers tune/map on the engine dyno since all loadings and conditions can be repeatedly replicated.

Thanks for sharing

 

To clarify:

The crank is designed to withstand the high revs and high load in both turbo and NA applications.
There are actually two specific designs one for the NA car and one for the turbo.

The engine is broken in on an engine dyno- power is verified on the engine dyno (the tune is done on this engine dyno).
We also install the engine in the vehicle and then do the final calibration and optimization on our chassis dyno test cell. We are one of the few shops on the west coast that have a proper test cell to simulate road conditions.

Just as an FYI Porsche Motorsport NA is less than 30 yards away from my front door. We have a very close working relationship with them in addition we have full time engineers and engine specialists on staff.

Rest assured the engine is a properly designed and engineered package able to take on the best the world has to offer.


And lastly to answer your questions we have engines in the field with our package and the components have all undergone testing. We are not a company to introduce a product in theory and test it on the consumer.

If you ever find yourself stateside please feel free to stop by , I would be very happy to show you what we do.

 

I wouldn't say that - you retain thicker cylinder sleeve walls than doing a 3.9, for example. Note that any size 4.0+ requires machining. The Piston ODs represents what's currently available on the market.

 

from now on pls stop linking google ..obviously you can't search.. (and it's your homepage 'n all..) : )

 

The table of numbers you've posted suggests thinner cylinder walls and doesn't include a 4.3 example. This Mahle setup from GMG and the RS Tuning 4.3 presumably run machined cases with reinforcement and cooling changes to handle very high compression (say high 12's) which all amounts to a lot of variables. In any case, once a 3.6 case is asking to handle a 4.3 displacement, that's a big bore and stroker motor. It will either rev like a slug or it will require rebuilds (anything above a 3.9 is a slide down the diminishing returns curve) and it's taken Porsche to build a 4.0 that can go in a warrantied car and be, as Mr Preuninger puts it, bulletproof.

That said, the idea of a 4.3 is appealing!

 

Very impressive.
Looks like GMG has addressed all of the engineering specs to make sure this package works in harmony with said parts.

The machining on the crankshaft and the porting on the heads, looks amazing.

I could mount those pieces in my living room as "works or art"

Keep us informed as you move forward with this 4.0 litre engine.

 

[QUOTE=Carrera GT;8566030]The table of numbers you've posted suggests thinner cylinder walls and doesn't include a 4.3 example. This Mahle setup from GMG and the RS Tuning 4.3 presumably run machined cases with reinforcement and cooling changes to handle very high compression (say high 12's) which all amounts to a lot of variables. In any case, once a 3.6 case is asking to handle a 4.3 displacement, that's a big bore and stroker motor. It will either rev like a slug or it will require rebuilds (anything above a 3.9 is a slide down the diminishing returns curve) and it's taken Porsche to build a 4.0 that can go in a warrantied car and be, as Mr Preuninger puts it, bulletproof.

That said, the idea of a 4.3 is appealing!

Look a little closer - the bottom right hand cell is the "4.3." The actual displacement is 4257cc. "Marketed size" row represents stock stroke of 76.4 mm.

 

If marketed size is 4.1 and displacement is over 4.25, which engine is it?
Still and all the same, wall thickness is less on larger displacements give or take whatever the "3.9" might be in this table -- where did these numbers originate?

The 3.9 uses the 3.6 or 3.8 crank, but still, it's an outlying number for the wall thickness. I guess that's why the 3.9 can be built with a P+C kit in the stock case.

 

The numbers are based on the pistons that are out on the market for GT3 application. I'm just trying to illustrate that there are many possibilities, and that when you go with a 105.4 mm or larger piston, you have to machine the case/cylinder housings to accommodate larger sleeves (110mm OD). From what I gather, the 3.9s built by sharkwerks use the 104mm pistons and stock stroke (3894cc).

I'm not saying one way is wrong and another is right - there are several routes you can take. For my personal build, I chose to go with 105.4mm pistons and retain the stock crank (this gives you 4 additional cc over the GT3 4.0 ).

GMGs build parallels that of the factory 4.0, so you know it's a proven design.

 

A pic of the crank piston and rods.

Sorry for the delay in posting these.

Enjoy.

 

I am seriously thinking about going this route.