What to build- 3.6 N/A or 3.6 TURBO

[herman maire]

I have been thinking about this for too long and I still can not come to a decision on this matter.

I have been thinking of 2 options.

#1 N/A 993 3.6
1-STB set up (INTAKE)
2-aggresive cams (7500-7800 RPM- Red line)
3-after market EMG
4-aggresive exhaust
5-upgraded -ROD BOLTS
6- NO POWER STEERING

With this set up I would hope to expect at least 325-350HP

#2 Turbo- N/A donner 993 3.6
1- single turbo
2-JE lower comp pistons- 8.5ratio maybe 9.
3- aggresive cams (6900-7500RPM-red line)
3-after market EMG
4- upgraded rod bolts
5-NO power steering

Expected power 380-425HP . I will not be getting crazy with BOOST.


What set up would be the most rewarding??? Stronger turbo VS weaker N/A.

For some reason I am favoring the weaker N/A set up just because throttle responce + sound will ( I think) be so much better on the N/A set up also I would not have a heavy turbo hanging out back.

Then I think of the power a well set up turbo has available and the money I would save on the N/A STB set up .

MY brother and I will be building the turbo set up + the help from fellow pelican's so I will not be paying a shop for any work .

I would really apreciate any opinion's on the N/A VS TURBO

[kenikh]

A redline that high on a 3.6? Isn't that asking for trouble? I'd build the turbo; I think the motor would live longer.

[herman maire]

Originally posted by kenikh
A redline that high on a 3.6? Isn't that asking for trouble? I'd build the turbo; I think the motor would live longer.

Really..... I would like to think that 7500RPM red line would be on the cautious side, maybe 7800RPM is pushing it, but 7500RPM... I will be very surprised.
I mean its really only 600RPM more than stock.

I am really after the most electric driving experience possible. I know that a turbo will be faster but I just feel that some of that edgy character of a N/A would be lost with a turbo.

I wish I had more experience with these 2 styles of cars.

[89turbocabmike]

Herman, turbo will definitely give you that electric feeling. You can machine down the stock mahle pistons(per henry@supertec) for the cr you want and save the JE money. With the increased displacement, CR and efi you will definitely achieve better drivability than a cis 3.3 that you've heard about/or perhaps driven that you feel isn't edgy. A quick spooling turbo will also help since all out power is not your goal. Turbo=ELECTRIC....but then again I'm a bit biased

[dean]

I am biased also. Go turbo. Every car I have has a turbo. I have had a turbo on at least one car I have owned since 77 save a couple sad years in the mid 80's.

So why don't you try to go for a ride in comparable cars and see which one floats your boat. Or you could just do the right thing and go TURBO

[Steve@Rennsport]

Hi:

You've gotten some great advice, especially from Dean,...

Get a ride in both kinds of cars and make the decision based on that experience and your preferences.

I happen to prefer N/A engines with really sharp, crisp throttle response that have a lot of snap. For twisty kinds of roads, its hard to beat a 3.6-3.8 with ITB's, the proper cams, and a good Engine Management system. Combined with close-ratio gears, its really neat,...

[RarlyL8]

Your choice dependes on what you want to do with the car, what your driving habbits are, and what exhaust sounds "do it" for you.

For example, if this is a steet car that will be driven often and taken on short trips you probably don't want a high strung N/A engine.
If the result desired is a dual-purpose street/track car that you wish to hit the back roads with and frighten children and small animals then by all means do the chainsaw N/A motor.
The difference is not so much power but how it is applied. The turbo is stealth power. You can have a quiet exhaust and a smooth idle with the same HP as a well built high-strung N/A motor.

[beepbeep]

I would opt for turbo.

First of all, highly strung N/A engine will need to spin fast, and spinning fast will wear the engine more. Also, 3.6 is a perfect base engine for turbo-conversion as it already have twin plugs and everything else.

With well-matched turbo you'll make 500+ hp w/o revving to high heavens. You will also accellerate away from even the most extreme N/A 3.6 you could possibly make (using cubic dollars).

Even if it sounds weird, turbo converted 3.6 is most bang for buck you could get, horsepower-wise. Use JE or even OEM 3.6 turbo pistons.

Swept area under power curve is what accellerates the car and turbocharged engine will accellerate faster than N/A of similar power thanx to much meatier torque down low. N/A 3.6 spinning at 7500 RPM will have lifetime of a butterfly, will cost a fortune to build and will be beaten by warmed-over 3.3 with slightly raised boost. Yes, there is a difference in engine responce but I personally wouldn't pay a premium and loose so much power just to have good throttle response.

So yes, go turbo.

[BReyes]

I would get the turbo set up. Why such a high CR? Yet, your first option also results in a proven performer on the track.

Regards,

[herman maire]

Thanks for the info guy's.

I will say that I am far from commiting to N/A or TURBO yet. I did enjoy reading everyone's case for builing a TURBO. ( Goran, Dean, Rarly I am not the least surprised heh, heh.)

I guess what I keep coming back to as a comparison is the 996 GT3 VS 996 GT2. Almost everytime it seems that the N/A GT3 gets the "nod" for the most rewarding drive even though it is underpowered and might get passed on the straights. This is what fuel's my indecison.

I am really surprised that a 3.6 would have the " lifetime of a butterfly" (Goran heh,heh funny but sad I guess). So if 7500RPM is pushing it, would 7200RPM be a happy medium??

Goran- You pointed out that if I was to go with a turbo you mentioned
JE pistons or OEM 993 turbo pistons. Would lowering the CR on my stock
pistons like Mike Mentioned ( Henry@supertec)????

If I recall IF2 had piston problem's with the N/A pistons it first ran... right?? Also what CR would you run to minimize lag??? I am thinking 8.5 or 9 to minimize lag but I know this will limit the Boost I can run.
I will be running a aftermarket EMG
I have many, many questions.


If anybody has any opinion's or experience with tuned N/A VS TURBO
please let me know.

[beepbeep]

IF2 still uses OEM 993TT pistons. It was dynoed to tripple the power you'll ever extract from N/A 3.6. It never ever had problems with pistons itself but motor was cammed to produce peak power @ 7500 RPM. As OEM 993TT pistons are quite heavy, OEM rod bolts took a beating at those revs and had to be replaced due to wear. It never used OEM N/A pistons.

For moderate power (<500hp) you could use 993TT pistons all day long as long as you don't rev beyond 6500 RPM. With matched turbos, you can make a killer motor for moderate $$$ input and drive it for a long time w/o costly rebuilds.

Or you can go the N/A route, buy unobtanium ITB's, headers, rods and pistons, rebuild it every year and still get spanked by some bloke reving 5500 and boosting 1 bar. You can always listen to the noise but noise doesn't propel the thing, it just makes your ears ring

[RarlyL8]

Herman, I am not as biased to turbo power as you might think.

Re-read my post above. Truely, you must think of how YOU wish to drive the car. Some folks can handle a chainsaw motor all of the time - that is their personality. I'm too old for that now. I still like power but for the long haul my butt wants a nice idling car with an exhaust note that won't have the neighbors throwing rocks at me.

Here is what I had before the turbo. This baby ROCKED! Sounded like a mad banshee and carved up roads like a go cart. I miss that car soooooo much.

[Wayne 962]

I like non-turbo cars personally, but I also like the thin-boddied early 911s too. It's really a matter of preference, although a non-turbo will undoubtedly be less expensive...

-Wayne

[911teo]

Originally posted by Wayne at Pelican Parts
I like non-turbo cars personally, but I also like the thin-boddied early 911s too. It's really a matter of preference, although a non-turbo will undoubtedly be less expensive...

-Wayne

I don't think a 7.500 rpm N/A engine will be less expensive than a moderate boosted turbo engine...
I am building one and we are changing rods, valves, lifters, retainers etc. to obtain a decent longevity from the engine.

So I went the N/A route. I didn't need/want 500hp on a 2,500lbs car. Like Steve said above the N/A engine will have a fantastic throttle response and it will sing to you.

The big advantage of the turbo will be the torque avaliable at very low rpms (compared to the highly strung N/A engine you have in mind).

If I were driving mostly on the highway, if this was going to be my commuter car and I wanted a less "tiring" car to drive I'd go for the turbo.

Plus I think the turbo would be much cheaper to build. As you said just lower the compression ratio, get a good EMS and you are done.

Having said that would you rather drive a 73RS, or a 930? A 964 RS/993 RS or a 993TT, a 996GT3 or a 996TT.
I realize in those cars is not just the engine that is different but the whole philosophy... but you can easily tell which power delivery you like better... I guess it could be difficult to test drive a 73RS... but u can easily compare 996TT to GT3.

Do it, and focus on just the power delivery, throttle response etc.
The 996TT will exhilarate you on coming out of a turn, when in 2nd gear at 2,300rpm you press the right foot.... BAM!
The GT3 will give you pleasure at the other end of the spectrum.
This is why Steve W mentioned the close gear ratios... U want to come out of the same turn at 3,400...

Keep us posted though! Good luck!

[Cookie Porsche]

Depends - some like reds, others blondes...

I disagree with everyone - no 911 engine is cheap!

However, we build a 3.8 7500rpm engine with ITBs and all the goodies and it runs and sounds like nothing on earth. It will pull from 2500rpm like a train and the sound is goose bum stuff. The response is awesome, intake sound is awesome...

You get the picture.

Now I'm building a 3.0 non-silenced twin turbo race engine. It is also not cheap! We're using smallish turbos and a battleship sized intercooler - so I hope for a realistic 450bhp. I think a turbo can sound awesome, the whistling, the blowing, the fire spitting exhaust, etc...

You get the picture again.

I'll never part with my N/A and I look forward to my new blown experience. Kind of having your cake and eating it.

Evolution is part of the fun. Start N/A and evolve.

[petevb]

A couple thoughts.
1. I'm wondering what car this is going into, and what trans you hope to use. Turbo motor = no 915, which can lead to a slippery slope, or a different, heavier car.
2. A "wild" cam on the 3.6 motor will be limited by the valve relief. So if you use the stock pistons you're either stuck with 993 cup/ GT2 cams, or you do different pistons (not sure about the practicality of piston mods). If you don't do the pistons it makes the engine management and ITBs a bit of a waste. If you do pistons, might make a 3.8/3.9 more attractive.
3. Data point for the N/A motor- my just dynoed motor is similar to what you're talking. 7500 rpm redline, cup cams, Vram, RS valves, lightweight retainers, custom burned chips for both 91 and 100 octane. Makes a bit over 320 hp on pump gas, and about 330 hp on 100 octane.

I went the high revving NA route for the reasons you listed. After owning a bunch of fast NA and turbo cars I find I like the NA significantly better if it's "fast enough". In this case I decided 330 hp and 2000 lbs is fast enough, at least for now.

[strokher racing]

I would go with the 3.6 turbo route hands down. You can easily make 600+hp with a basic long block

[Wayne 962]

Originally posted by 911teo
I don't think a 7.500 rpm N/A engine will be less expensive than a moderate boosted turbo engine...

Longblock, no. But everything else required makes it an expensive proposition...

-Wayne

[Jeff Alton]

You are telling me!! I just added up my cost to date on my 7500rpm 3.4 with ITB's and programmable ECU....... OMG!!!! Wish I did not own a calculator!!!!!!!!

But then again, I prefer the feel of sharp throttle response over the big turbo rush, makes the car more drivable on the track with my moderate skills.

Cheers

[dean]

Here is my data point

My fairly stock 3.0L 930 with EFI puts out 350 RWHP on a DynoDynamic dyno. That was at 13 lbs of boost. Those ain't no DynoJet #'s. I have now turned the boost up to 18 or so.

So I think if you want to make power go turbo and if you want to make noise go N/A Sorry I couldn't resist