![]() |
Quote:
Best advice, don't waste your time. |
Go buy a Vette if you are that kind of driver. I think it would suit you better.
|
Alright you guys obviously lost the whole idea I have. Yes if I was into that stuff i would get an american muscle car, but i have a porsche and I dont plan on getting rid of the car. I just wanted to get more power out of it, like everyone else likes to do once they get used to the speed of there car..
|
Here is some helpful info from the pca website.
The best overall summary on this subject is in Bruce Anderson's "911 Performance Handbook, Second Edition," published by Motorbooks International. In order to get more power out of the engine, it has to be able to pump more air at a higher rate. In general, there are two categories of improvements for this; external mods to the engine and combined external plus internal upgrades. Your question seems to refer to just external changes that can be made to the engine. On the 3.2 911 Carrera, enough test data has been done to show that most of the external gains that can be made are in the exhaust system. Short of changing the mass air flow sensor to a hot wire device or converting to carburetors there isn't much that can be done to improve the engine intake airflow. Tests without any air cleaner at all on the 3.2 have been shown to be within 0.5 hp of the factory air cleaner, so it is unlikely that something else will improve on it. One of the biggest areas of improvement possible is the exhaust system to eliminate the crossover exhaust from the right hand bank to the left hand bank and get back to the 1974 style 911 headers with each bank separately feeding the muffler. Bruce's book indicates the exhaust change is worth about 13 hp and the best chip they found was worth about 9 hp. In a few cases they investigated, combining external gains would approach a hp level of 240 for the 3.2 engine. Beyond that, increased displacement and internal changes are required. |
Quote:
|
I think that 13 hp was at a lower rpm not peak HP and this was with a sport muffler on top of the back date.
All the info I have seen after BA's book indicates there is a little added bump at around 3K rpm w a back date or SSIs but past that the hp is the same as keeping the stock heat exchangers with a change to a cat bypass or euro muffler. The gain is about 7HP. Adding a sport muffler on ether of these adds about another 7hp. The SW chip seems to be a winner. I belive the reason the 3.2 responds so well to the exhaust is because the factory runs there chip rich I am guessing as a protection above 5k rpm where the AFM seems to stall and there is no longer any real measurement of the air flow. Adding a lower restriction exhaust flows more air and gets us to a better AF ratio. On earlyer cars like a 2.4s adding a sport muffler made the car run lean. With the right mods, some belive the intake manifold responds to porting or extrude honing. I am doubtful unless the motor is enlarged and or a higher rpm cam is used with good exhaust changes. With a cat bypass and chip I am pulling 215 rwhp (250 fwhp). A friend w a sport muffler cat bypass and chip got another 6hp on me. For compairsion, another friend has a 2.8 RS mfi twin plug motor and full race mufflers pulls close to 200rwhp. I think the factory HP ratings are a bit constitutive or something. I suspect we are very close to what a euro car would pull w good gas, a premuffler and a stock chip (231). Get the weight down by 450 lbs (15%) with a well tuned stock motor(+10%) and it should be pretty fast car. Just some opinions for what I have read and seen on my 85. |
Just look at the link(build) in my sig then you will be all set
|
Quote:
2nd 63 3rd 95 4th 125 5th 150 |
Quote:
That's the key. To get more power out of a 911 costs cubic $$$. You don't really get much power out of a chip, and you don't get any power by cutting or drilling the airlid of a 3.2L car. The 3.2L cars have been dynoed and found that the airbox was not a limiting factor for making power. Exhaust would be a limiting factor. If you can get rid of the cat and go to a equal length dual exhaust with a dual outlet muffler, that should make an improvement. I think much past that, and you have to start looking at taking the engine apart to replace rod bolts and cams etc.... That gets $$$ Strip the car down as light as you can get it. A targa will be a bit hampered because of that giant (heavy) rear window and the top. If you want a faster 911, you could always swap in a 3.6L out of a later car. That should run you about $10-15k. |
If you don't care about keeping it original, this is the best bang for the bucks. Lots of bucks, but lots of bang:
http://forums.pelicanparts.com/showthread.php?s=&threadid=176597&highlight=protom otive But, to repeat a previous post, turbos make lousy drag cars because of the "...not yet... not yet...NOW!" kind of acceleration, i.e. more high end HP than low-end torque. If you want a "stoplight stormer", go "old school" with an engine swap: http://carscoop.blogspot.com/2007/06/porsche-911-with-chevy-v8-transplant.html http://forums.pelicanparts.com/porsche-911-technical-forum/320884-small-block-chevy-v8-powered-911s.html?highlight=chevy+v8 After all, a Cobra was just a British sports car (AC Ace) with a Ford V8.... ;) |
Quote:
A member of this forum got into 10s with a turbo 3.2 with stock internals. |
Spence88mph -
You are absolutely correct, if we were talking about a timed 1/4 mile, but the original topic appears to be more focused on stoplight street drags, where the first 100 yards or so are the most important. Implicit in my previous message was some not-too-subtle commentary on the kind of modifications to a 911 required to focus on that kind of inappropriate (IMHO) but admittedly entertaining street racing. Either get a 'vette or some v8 muscle car, or put the engine from one in your 911. If one wants to really enjoy their 911, don't waste time with street punks or rice burners at stoplights, find a good back road, or even better, when & where one can take their 911 to the track - and not a drag strip. |
dwi, I understand what you're saying but all I can say is until you experience it first hand you wont understand. A carrera running .7bar on a stock engine can do 0-60mph in 4.2 secs timed by Protomotive. Having that setup I can tell you it launches incredibly well with very little wheel spin as all the weight of the car is over the back wheels.
You're thinking of the laggy 930 style engine, not an efi 9:1 engine with a modern day ball bearing turbo, very different. Power is linear not on and off. The 911 is not a drag car we all know that but it is nice to waste a hero now and then though ;) |
So it looks like I will be putting a 3.2 (that I already have so don't tell me to get a 3.6) into my 77 widebody for the track. I want more than the stock power so what should I do to it?
My goal is 250 HP if possible. I am considering back dated exhaust (already on the car - it it big enough for a 3.2), chip, cams (which ones?), and possibly running webers (I already have some for the 2.7 that I would rather kep with the 2.7). |
Quote:
Mahle 10.5 p/c, twin plug, 1 5/8" ID headers, Motec(preferred) w/ ITBs or MFI or carbs |
I assume you're talking 250 to the wheels, correct? I'm making 213 to the wheels now w/ my near-stock 3.2L (no internal changes, stock air flapper, just a chip & bypass w/ M&K muffler, etc.). That's right at 250 crank hp with 15% driveline losses.
|
spence88mph -
Thanks for the clarification. I was indeed thinking of a 930-type turbo setup. I honestly didn't know that the Protomotive setup was that much different. So, you're running the "stage 1 upgrade" setup? Any problems/issues/enhancements? |
Yeah you can be forgiven, in all honesty I didn't believe it either until I did the kit, I was so blown away after the first drive, was such a rush to almost double the power over night (it really is a weekend job, once you've done one you could do it in a day). It's hard to believe how linear it can be, because you're not dropping the compression and using a turbo that spools up very quickly the power is so smooth.
No, I have run at .7bar on a freezing day a couple of runs but the car just runs stage 1 (.5bar) as I need to get an intercooler fabricated to fit under the lid as I don't want to mount the wing. Issues, the only issue I had was the stock porsche plastic elbow blowing off under boost, once I replaced it with a silicon elbow it's been fine. I really can't think of any shortcomings, actually you really need to upgrade the rear torsion bars as the car squats very badly! |
If you keep drag racing you will soon lose 1st gear in the 915. That gear box was simply not built for this. Mr Porsche once said cars have first gears only to get them to 2nd. Trust me you will soon be re-building that 915.
|
spence88mph -
OK, now I'm confused. You're currently running without an intercooler, as you don't want to mount a wing, but you're signature line says M491. An M491 without a wing? Also, are you running the stock clutch? I'm asking because I'm seriously considering doing this mod to my '87, although I'm also keeping my eye out for a good deal on a 930. FYI, my view of turbo "switch like" performance is also based on my dd - a late 90's Saab turbo, which runs 1.08 bar and comes on rather suddenly and entertainingly at about 2800 - 3000 rpm, but off boost is about what one would expect for a 4 cyl, 9.2:1, dohc motor in a 1370 Kg car. |
All times are GMT -8. The time now is 09:26 AM. |
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website