My custom Gt3 intake built by Billet Design
 

I thought everyone would like to see my finished intake for my turbo engine. It began life as a Gt3 intake and evolved into what you see here. All the fabrication work was done by Marco Manzie at Billet Design.
http://forums.pelicanparts.com/uploa...1152042854.jpg http://forums.pelicanparts.com/uploa...1152042893.jpg http://forums.pelicanparts.com/uploa...1152042935.jpg http://forums.pelicanparts.com/uploa...1152042983.jpg http://forums.pelicanparts.com/uploa...1152043019.jpg

Looks like it was cobbled up by the tin man - ;)

Just kidding -

Man - that donkey does some good work - looks like a work of art -

-Jeff

What modes did they have to do to get the GT3 intake to fit?
Also what motor is it going on?

BTW it looks beautiful, lots of detail and care was taken.

Is it plastic or Alu?

The intake has been cut and welded for runner length mods etc. He machined injector blocks to work with a 2 bolt head. The motor is a 3.5 stroker motor with a single turbohttp://forums.pelicanparts.com/uploa...1152045484.jpg

pichttp://forums.pelicanparts.com/uploa...1152045865.jpg

Nice...

I'm surprised that the intake on the GT3 is Alu, I always thought Plastic flowed better. Oh well... wrong again.

When do you plan to have this motor in action?

The intake is smoothed over internally:) The plenum area on this thing is huge which is great for a turbo motor. It is just a timing deal now to get all the last things bolted on and it is ready to go.

WOW!

that looks wicked


i'd love some more details on your 3.5L stroker turbo....

and some more info on your car...

that is going to be an impressive engine bay.

Curious at this budget why you did not go with a full Motec or similar engine management. I see you have the Dizzy still.

Beautiful work!!

Well, I think Eric got a great deal(sponsor?) on an accel gen efi system and that is the custom 911 accel dist. that supports sequential efi, so no crank trigger needed. Good to hear from you Eric, Get this monster on the road!!!:)

Looks like there are 2 plenums - one on each side?

What model was used to calculate their sizes & placement re runner length?

WOW, that looks insane, Eric! Very cool :cool:

Must have cost a pretty penny :eek:

Not sure if you have ever seen up close or in real life the intake of a GT3/R/RS/RSR

Strokher has had a talented fabricator adapt a throttle body and modify the runners and crossovers to suit.. which look remarkably like the runners on a GT3 RS I know.

The last two places this manifold raced were Le Mans, then Watkins Glen

This one is from Porsche Motorsport..for a supercup engine.. circa 2001

http://forums.pelicanparts.com/uploa...1152067049.jpg

Hey Eric I almost popped for the same intake but Marco being the class act that he is told me that for street applications the 3.2 Carrera intake did the job as did Bob Holcombe for that matter. It does look awesome though.

Huh?

The one in the pic above has single plenum and it is at least 4x the ones on the red induction unit....

I have a JB racing 12 plug distributor on the engine and a crank trigger. That is the old accel dizzy in the motor.

I'm curious about the twin crossovers, why not just one large one? Seems to me like the front crossover will do little but provide volume. Wouldn't as single crossover centered between the end plenums work better?

Yes there are two plenums on the intake. Alot of R&D was taken to adjust the runner length etc to get it where it is at. The dyno will be the final test of what it will do. I have my hopes high on this intake

What size/make turbo are you useing?
Sure looks impressive.

The turbo is a custom 74mm unit from Job Spetter. The wheels in this thing are not run of the mill so you can't compare it to another 74mm. This turbo has already made well over 1000rwhp which is alot for a 74mm unit. It would not hurt my feelings to max it out:)

Good luck -- if you need to revise it, a flow bench can most of the non-resonant tests that a dyno can do for much cheaper.

It was not a new design. The intake is based on a gt3 so a flow bench is not needed Porsche took care of the majority of the work. Runner length and center section design are the main differences. The plenums are the same except for cleanup work. A flow bench would not do anything here.

The dual crossover is for the reversion flap, which is stock on a standard GT3 Cup. Some GT3 Cup engines have a big piece welded onto the back and the internals gutted out (an effective single crossover) for a little more power. GT3 RSR and DP engines both have ITBs (which is why TimT's manifold looks so much different).

What exhaust and cam are you running?

custom cams and headers also built by Marco. The center section on my intake is a very trick unit with internal diverters to smooth out the entrance.http://forums.pelicanparts.com/uploa...1152146287.jpg

Whoa, you're using a naturally aspirated intake on a turbo car? I'll be curious to see how this works.

The cross-over might also function like the old-timey "balance tubes" on some motorcycles...


"naturally aspirated intake on a turbo car"

- This is a very interesting amalgam... we'll all be interested in the dyno results.

NA intakes are what most people use on turbo builds. 964 intake, 3.2 intake etc. This intake should be an animal with forced induction

I'm not saying it wont work by any means. But my understanding of cams says it will be a challenge to maximize the power. A cam works based on intake and exhaust pressure/velocity. I'm really a student to engines right now, so I'm curious to see what works that isnt written in a book or being practiced by Porsche right now.

This intake is gonna be great for a boosted car. The people are doubting this havent seen one in person. It has large plenums and large runners, which are ideal for boost. The runners were shortened to help shift the power band to higher rpms. The dual crossovers help with volume. I'm thinking of ditching my ported 3.2 for one of these.
and on the note of cams, a boosted car loves overlap and high lift. There is this myth that u can't have any overlap blah blah. Alot of what u read and hear was true 20 30 years ago, things have changed alot.

The dual crossovers help with volume.
- The vol. of the induction?

Has better engine mgmt. allowed greater overlap? If not, what was the change in the last 20-30 years?

This is not optimal design for turbocharged engine. Alla that resonance tuning stuff is just dead weight, especially if not connected or actuated by any device. GT3 and all...you would be as good with ordinary Carrera plenum or even better with custom made twin hi-volume-long runner plenums. Air that enters the throttle has to makee sharp 90-degree turn into each side of plenum. Balancing pipe doesn't do anything else but increases the volume of plenum.

This, on other hand, is optimal turbo plenum:
http://www.itsfun.nu/if2_2006/0403/if2_011.jpg


Boosted cars do not love lot's of overlap...it tends to blow out the charge trough the cylinders. It all depends on turbine size and amount of backpressure but lot's of overlap on turbo engine usually leads to inefficient engine with slightly more power.

holycrap Beepbeep, those are HUGE!

I always thought the low overlap was ideal because ...just like beep beep says the charge would blow out the intake. I liked this because its intuitive. I think this is also the reason SC cams were a good upgrade because the CIS is so sensitive to intake pulses they have no overlap...ideal turbo cams.

Please expand on how overlap could possibly be good on a modern turbo engine - seems like you are fighting physics.

I am not doubting any one just curious.

Yeah, but then again what does Goran know? All he does it take pictures of the slow car him and his crew built. :D ;)

Even if it sounds confusing when I wrote "slightly more power", I do mean that hot turbocharged engines with lot's of overlap tend to have bad character and are not as responsive as correctly cammed ones, despite the possibility to extract the torque curve upwards in the rev range and thus achieve higher peak power figures.

imagine two engines: first dynoed @ 500hp with very flat torque curve and nice & predictable boost buildup and second dynoed @ 600hp with help of very aggressive cams but with peaky power curve and sluggish boost buildup. What you gain up top you loose longer down and sweet spot is often lower down than dyno-loving drivers believe. Of course, as revs go into strathospheric range, hi-overlap cams tied to correctly tuned runners will hit it's sweet spot and make more power than low-overlap, but this range is usually quite narrow and hard to use on circuit, unless you have CVT tranny tied to the engine.

The car equipped with first one would walk all over the other despite the lesser peak hp figures, thanx to it's better dynamic range.

It's swept area under power curve that matters, not peak hp figures.

Goran, I think that engine design in this respect is WAY overlooked. Hot rodders so often try for high numbers rather than motors that are flexible and have a wide powerband. Damn you freakin Swedes know whats up. I would love to see the kind of stuff you guys build on your own time.

hey now i didn't say lots of overlap. i've found that some over lap works well. To be honest i've found that cams with lots of lift with the overlap dialed out work very well. This is not always 100% true but i think most of it has to do with the fact that cams with lots of over lap tend to have lots of lift. I know this isn't porsche related, but i built an engine(honda twin cam) with cams that that had alot of overlap and high lift, we dialed out some of the over lap and made extremely good power for what it was. The tuner (who is nationally known) was didn't think the cams would work at all, he now says that they are his cam of choice for a boosted car. the cam is know as being an excellent NA cam. We also managed to make a t67 turbo spool faster than most 60-1's with the same turbine wheel and hot side are., i think that alot of that was also due to the large lift on the cam. I'm not just talking out of my ass here, i have a dyno so the engine i speak of was probably dyno'd for a good 40 hrs or so within 3 days. we tried every possible cam gear combination, when we dialed out all of the over lap the hp started to fall, maybe have been to the timing chaneg, and yes we changed the ign time each time to compensate for change. Another time we actually had turbo cams in an engine, and made more power with a stock cam, i personaly know that the low lift no overlap stuff is BS, it was true years ago but it was more due to engine management and tuning than it was the cams.
And to keep on topic, yes a large plenum is ideal, if u have seen erics intake, they have alot of volume. I'm sure the twin crossover work, if u look at alot of the boosted f1 cars(which i believe are more tech. advanced than most turbo cars that are built today) have crossover tubes. they were making 1000hp/liter over 20 yrs ago. Too bad most of there tech was destroyed and the secrets mostly gone forever.

someday we will be able to open and close the ports when we want and as fast as we want...

think about it -- a lot of engine design and tuning is based on trying to deal with the above problem...