DYNO numbers for my 76' 2.7Turbo EFI(Tbitz)

[bb]

I am going to calibrate the LM1 again this weekend. I am running the RAJAY turbo, will find out the model. I am running the MSD timing computer hooked up to my MSD 7btm. I have it set at 35 degrees. I still need to look at the ignition and other things, I just needed a starting point prior to making any changes.

I am also going change the pipe that goes from the headers into the tubo...make it bigger. I had made it smaller to see if it would make the turbo come on earlier. I think it worked backwards

[bb]

pic's of exhaust pipe
and motor

[bb]

Here's picture of pipe I made to hook up turbo

[bb]

And of course the had to have gratuitus picture of the car

[tobluforu]

That car is sweet, but it's all show and no go. Heck my saab dynoed at the wheels with 236hp and 267ft lbs of torque. Ge that bad boy tuned.

[Huh]

Do you have a boost gauge? Is it calibrated? I can't believe that your wastegate isn't holding boost longer than 4.3psi. I would expect more like 7lbs or so with that 9lb spring. Running lean at high rpms isn't good of course. That Rajay turbo may not be super efficient either. I have one sitting in my garage and it is pretty old technology compared to my old silver dollar sized turbo from my GTi. You may want to check your wastegate for stickage. Also if you use a manual boost controller you need to make sure your wastegate is functioning properly or it is just boost going out to the air. If you run 8-9lbs you should be in good shape for some decent hp but that will depend on your fuel injectors, fuel pump and delivery, last but not least your compression.

[bb]

the show was easy now we are going to make it go. I know that I can make more power and this is the fun part.

[sammyg2]

That header pipe is waaay too small. Velocity is not a concern unless it is choked down (which yours is), the heat and pressure are the energy sources. the desire for the hot pressurized exhaust gas to expand and cool is what drives the turbine.

Open that bad boy up and you will be giggling.

[bb]

what diameter do you thing I should go to? The headers are BB.

[A Quiet Boom]

Originally posted by bb
Christian, I am running a LM1 Wideband sensor. That's why I was confused. My readings kept showing me that I was at 12.5 but they kept saying that I was lean. The guys at Akron Horspower are pretty cool. Was almost embarrassed the car before mine was a plain looking Mustang that they had tuned for the kid at around 550rwhp.

Mustangs are easy to make big HP numbers with. 550rwhp in a Mustang will put you solidly in the 10's in the 1/4 mile on slicks and a good suspension. Be leary of these cars what looks like a 5.0 (302) could easily be a stroker 347 or a 351 like I had pumped out to 410 with 650hp and no power adders (ie supercharger or nitrous). Now try to get a Mustang to handle and brake like a stock 911 and you're gonna spend big dollars. Heck just to get one to last at high revs like a 911 will cost some cash as well. Remember your 911 is never gonna be a straight line car, the fun is the whole combination of power, handling and braking. FWIW My little car weighs in around 2100 with me in it, I have lots of fun with guys in slightly modified Mustangs. I've got roughly the same rwhp of a stock 5.0 and 1000+ lbs less weight. My stripped drag car with a full cage and lots of heavy duty parts tipped the scales at 3200lbs.

I've got a printing press here at work, I wanna make a decal for the rear window that says "Sooner or later everyone has to turn..."

Guy's I've seen Oscar's car in person and let me tell you it's beautiful, get the "go" working right and it'll be a hell of a car.

[tbitz]

Looks good Oscar.

Here is some math to make sense of the numbers. I looked in BA book and a USA 2.7L engine made 165Hp@5800rpm.

Assume turbo compressor is 75% efficient.
Assume your intercooler is 75% efficient.

By adding 4.3psi of boost, calculations show that the HP should increase to 208Hp at the crank.

You got 189Hp at the wheels. If you assume 12% losses, then your Hp at the crank is 189/0.88 = 214Hp. This 6Hp more than estimated. EFI probably has something to do with that.

So your dyno run correlates to theory somewhat. Now if you boost to 8psi theory says you should get 244Hp at the crank.

Note that the temperature of the air out of the compressor will be 54C higher due to compression and losses in compressor wheel. A 75% efficient intercooler would drop that temperature by 41C with an end result of only 14C higher engine intake temperature.

....and just for fun, if you boosted by 14psi, theory says you should get 300Hp at the crank Not sure how long that would last though.....

Cheers,

[quattrorunner]

Oscar, I have seen that car. Have you had it long? I saw it for sale on ebay a while back. I liked it then and at that time it had efi and turbo. That was at least 2 years ago. Cool car and when it gets tuned? Cool.

[bb]

must have been a different car. I have never tried to sell it. I just finished the EFI conversion last year. This is the first summer that I finally started driving it everyday. It is very dependable and runs real strong with Tony's kit

[quattrorunner]

Hmm. Well good looking car. Have fun and build that boost.

[bb]

So where should I start in regards to getting more boost. I am thinking of capping off the wastegate to see if I am blowing off boost there. Then I would make a new pipe to connect the headers to turbo...or go to the original exhaust that came whith the BAE which is the regular 911 exhaust.

[sammyg2]

Double check the mixture readings, they said you were lean and the LM-1 said you were rich. One was right and you really need to know which one.

go back to original BAE piping, or at least make the header the same size or larger than the bae piping. I have the stock BAE piping and have no problem hitting 8 psi boost.


Iffn I were you (and your glad I'm not) I would not cap off or disconnect the wastegate. Boost climbs real fast, faster than you can react.
I accidentally disabled the wastegate on my 914 turbo once, it buried the 18 psi guage I had and the pinging noise could be heard across the street.
No good, I was lucky I didn't break something.

[mb911]

well oscar I hope it works out. I will be running my car this week and using a widband o2 to help set everything. I hope to get 275 at 6-7 psi with my 3.0 and tonys efi kit . What do you guys think?? I won't intercool till I go more on the boost. In case you missed the picture here is as of now. Should be running monday evening and then tune at home for the week and then find someone local that knows mega squirt for tuning

here is the link to my project. if I can help let me know

well finally started the install this morning

[sammyg2]

A stock 3 liter with no intercooler will prolly hit 250 hp at the crank at 6 psi and 91 octane. Maybe a little more depending on ambient temps.
If you can get it to 9 psi you will be in the 280+ range, but that will prolly require intercooling with pump premium gas. You can run it rich or back off the timing, but both of those things take away power as well as reduce the tendency to ping. You give up as much as you gain so all you end up doing is reducing the efficiency of the engine.
I figure anything above 6 or 7 psi requires a decent intercooler with the CR and gas we are running.
That's why I have stopped at 7 to 8 psi, I figure that's the safe limit with my setup.
Sure I could go richer or back off the timing, but the net gain would be minimal if at all.
As it is, 260 hp (guesstimated) feels like a million in an otherwise stock SC, well worth the money ($1200) and time.
Even if I have less power than that it doesn't matter, every time I give someone a ride and the boost hits in 2nd and 3rd all they can say is holy *****!
The car is fast enough to keep my attention and occaionally scare me. What more could you ask for from a CIS 3 liter that can be regularly driven on the street reliably and can be taken back to stock in a few hours?

[mb911]

sammy you never backed off your timing????? its still the stock setting?? just curious. Oh and I plan on running the same intercooler set up as oscar but I am running it both ways mainly for ease right now(don't want to cut up the engine lid right now, I want to drive it until winter)

[sammyg2]

5 degrees BTDC with 12.5 to one A//f ratio and between 6 and 8 psi depending on the weather and how hard I'm going to drive it.