What would it take to twin turbo my 3.6L engine?
There's a few obvious changes, but my guess is there's a lot more to it.

Could any of the newer factory setups be adapted to fit my engine?

Many cubic dollars. Other than that I got nothing.

What about a supercharger? Way less plumbing. No internal mods. 400hp. $7,500

What he said...I know TPC used to offer this 3.6 setup. Contact them for their thoughts (I know someone there if you need a name to drop).

Superchargers do make a delicious whine as they wind-up

Doesn't the whine screw up the knock sensor?

Lets see a maga-squirt and some staged turbos, and a plastic seat cushion for easy clean up when you unleach the beast. Man that would be a lot of GO?


jcl

Megasquirt is not sofisticated enough to run staged turbos. You need high end EFI stuff for that. Figure $10k for an engineered twin turbo system. And a full rebuild of your engine with all new internals.

All you need is one, two for cool factor only...... believe me....
Marty is running dual turbos he could tell ya...

Exhaust turbo = free HP and would be cheaper than the supercharger.

I removed the twin turbo from my engine and went with a larger single turbo. Way easier to setup. You want look at a Motech system as they are used in turbo Porsche race cars everywhere.

What's you budget?

The new variable vane turbos act much like having two turbos in one, come on fast and smooth. One single hits hard and makes things interesting quickly.....

Whatever i want it to be ...

Nice option.....better get busy only 8 months til the end of the planet.

Then spend the $$$$$ for a complete setup with engine and ECU. Sell you 3.6 to help finance it.

Did Ammoy get a job? (Don't let her see this, she'll kick my ass)

If your going to keep your 3.6, Why twin turbo? Whats your HP goal? 450? 500? 600? 700?


There is no need to run twin turbos on 3.6l's that is plenty of displacement to run a pretty large single turbo with VERY little turbo lag. Using some of today's turbo technology you can get some pretty impressive numbers.. I'd say go with a twin scroll ball bearing turbo. With a new fancy inlet (like Precisions HTA). Im running a Comp Turbo CTB5356 on my Audi 1.8L and with full spool under 4k rpm's i'll be looking at well over 500hp with the boost cranked up. Maybe close to 600 on race gas. As it is now I have it at 10psi and its making ~ 330hp and has wonderful driveability.

With 3.6L you could run a slightly larger turbo than that and tune however much HP you want and still have very quick spool.

Besides, there is nothing like the feeling of a large single turbo that wants to go more.. Oh man.. Ask Mike...

I think mine spools to quick. is that possible? I can get FULLLLL boost by 2000-2500rpm. It makes quick blips of the throttle really fun. Maybe I should let Andy drive mine?

Maybe you should let ME drive it.

You can only drive as fast as you see, old man But maybe... Beats getting a mustache ride from you

For some reason I knew this was coming....

It may be easier to buy a turbo motor...IC them for 15k-18k online on Ebay once in a while.
Call EASY...I bet he could find one.

Rich

Twin turbo might actually be easier on a 914/6 since there aren't any header (I know of ) that combine to a single pipe. So you could add a turbo onto the end of each header. Something like ottox914 did (build thread).

Plumb that directly to where you air cleaner sits now and then figure out the fuel injection situation. Something tunable would be my first thought, of course there are shops that seem to do amazing things with custom chips.

I would love to see a header that turned up at the end of the engine, allowed the turbos to sit near the flywheel, and then continued (post turbo) over the axles and out the back.

IMHO, plumbing is the easy part. FI is a tad harder....

No goal ...

No budget, no goal, no problem.

Sounds like you need twin garrett ball-bearing turbos and Haltech injection.

Click to view attachment
Like this...

So you wouldnt mind plopping down 15k and gaining 150hp?

When I bought my turbo for my Audi, I made a goal of spool, I wanted FULL spool by 3800 rpm. On my previous turbo I had full spool by 2700 rpm and in honesty it spooled to quickly. I would simply want to merge or drive a LITTLE quickly and it would just spool ridiculously quick. Keep in mind it being a 1.8L it doesnt have much daily driving tq below 2k so I would typically drive it 2500-3500. What I came up with was something that with the wastegate open as much as possible, will start making SOME boost ~ 2k and just keep pushing it up till its making full boost (at the moment) at 4k, which is 10psi (When I have my tuning software I'll adjust fuel trims and timing and close the wastegate more, which will decrease spool time. At that point the max i'll run is 30psi on race gas). Then it just pulls harder and harder till my ECU cuts at 7.2k, however I know this turbo will push me well into 8k rpms and still be within its efficiency.

If you REALLY dont care about the money, and you want twins.. your best bet would probably be a pair of GT2560's. This was what I had previously on my 1.8L, but in single form. It was the perfect match for my engine and it gave me an incredible spool factor but also pulled STRONG all the way to redline, Spool was literally instantaneous above 3500. Since you have twice the displacement, that should scale up. The 2.7L audi guys run them when they want 600+whp. You could even go a pair of GT28r's if you wanted more of a linear power band and not a big tq spike down low (This is the issue with small turbo's).

However if it was my money, I would make some calls to some of the turbo builders (034 motorsports is in your area, they do good work and have a dyno). And ask them what they think. I would think a nice GT35R or GT40 sized turbo (Comp turbo, precision, turbonetics are also good turbo's and have more advanced internals than the 20 year old Garrets) would work well. Heck with that size of an engine you could probably go journal bearing and cut your cost in half. A nice large Holset turbo off a diesel is what the cheap guys use when they want a factory reliable and big turbo for making big power..

No, I think Andy just wants to think, hear, and talk about all kinds of options before deciding on his goals. Makes for an interesting thread.

I bet using one k27 highflow on that 3.6 would be enough to scare the shit out of you in your 914.

I can tell you my car scares the shit out of me sometimes, and i probably have around 400hp.

I would give Marty aka Maltese Falcon a PM and ask him since he just went the twin turbo route on his car, plus he has already fabricated an exhaust system for one .

http://www.msdsinc.com

http://www.youtube.com/watch_popup?v=fhH5mzfyFl8

Thanks guys,
this is giving me some good pointers already ....

I haven't seen anyone mention what I would have considered fundamental to this mod. What about the normally aspirated compression ratio?

Wouldn't it limit the amount of boost you can dial in? I'd have thought it to need lower compression pistons.

That is my assumption. I don't really see the benefit to add a turbo to a 10.5:1 compression engine only to be severely limited by the amount of boost i can run.

Lowering the compression really is a must, IMHO.

This is why a large turbo is beneficial VS small twin turbo's. They are more efficient and dont create as much heat.

Also with a VERY good tuner, the higher compression ratio wouldnt be an issue, Sure you cant push the engine to the MAX but you can still squeeze another 50% out of the engine with ease. They'll mess with the timing and fuel curves to make it safe and reliable.

Running an intercooler would be necessary, also running water injection would be a huge advantage due to your compression ratio.

However with a "no budget" build (lies, all lies) yes some lower compression pistons should be in the mix to be able to push the turbo much harder.

How about e85?

I have been tinking about this too. I'm not that familiar with the 914, but here goes.

Thinking twin Mitsubishi turbos, GT28 or similar. If your arches are wide enough, you could possibly fit two smaller intercoolers in front of the rear wheels using an 996/997T type duct. In my head I would make up something similar to the 962 plenums

Not readily enough available. Bay area or LA, sure, but drive outside of that and there is one every hundred miles. Also gas mileage goes way down and it requires 50% more fuel at WOT. However its like 105 octane

He could then be called boosted corn from now on!

Or corn flake

Or the Cobb miester.

Or just corn hole!

I am disturbed by the lack of love for CIS in this thread.

CIS works well enough in my car, unless your looking to go 500hp or higher and
are looking for perfect AR across the entire RPM range then you need EFI.

CIS is certainly the cheapest fueling solution and starts great every time hot or cold
and doesn't need a computer with a tons of hours of mapping on a dyno.

i think the factory air cooled twin turbo would be a sweet engine to transplant into a 914. it is well designed and compact enough. i was wondering if the engine shelfs might have to be trimmed a bit. if you used this motor, lots of issues are already solved for you. engine ecu, wiring, injection, plumbing. might have to locate intercooler in rear trunk. i would love to try this now that i think about it some.
good luck...... danny

+1

No question either a supercharger or turbo(s) need less compression.

I kind of like the idea of a supercharger, for one primary reason. They are putting them on lots of cars and you won't be the pilot project. Also all the fuel maps will have already been worked out...developing fuel maps is expensive.

If money was no object I'd change my pistons and heads and bolt one on. Even my dinky motor would be good for probably 275 plus.. Might not last long, but torque is everything and superchargers will rip your tires off.

Here are some dyno charts that compare turbo to supercharger. You want HP or Torque?