| Author | Message | ||
| Rob Schermerhorn (Rexrcr)
Junior Member Username: Rexrcr Post Number: 167 Registered: 11-2002 |
Jay, I understand your perception of the twin turbo and whether it's 18 psi each or together. Basically, it's a twin turbo system. So, if one was jammed somehow, the other would try it's best to pressurize the intake manifold to 18 psi above atmospheric pressure. But one cannot say that turbos are "additive" in their output. Each contributes on a per unit volume flow rate. Each does have it's own intake, exhaust, and is responsible for providing one half (4 cylinders) of the work. In very simplistic terms, I guess you can say that each turbo is supplying 18 psi, but technically that statement is incorrect. Luke is right, turbochargers are like any other pump, they flow volume of a substance. They do not "create" pressure. It is the restrictions to that flow that sets the environment for a pressure increase in the intake manifold. Take a garden hose, "t" a pressure gauge to the side of the hose. Turn on the water full blast. The gauge will probably read below atmospheric pressure, close to full vacuum, say -14psi, assuming that "0" on the gauge is actually 14.7 psi absolute. Now put your thumb over the end of the hose, you're creating a restriction to flow, read the gauge, big increase in the pressure inside the hose, probably shows 40 psi or more. Hope this helps.  | ||
| J. Grande (Jay)
Intermediate Member Username: Jay Post Number: 1038 Registered: 10-2001 |
Luke, I understand that but doesn't each turbo have it's own intake? | ||
| Luke Wells (Coolhandluke)
New member Username: Coolhandluke Post Number: 21 Registered: 1-2003 |
Jay, Turbo's dont flow "pressure" they flow air. 18 lbs of boost means that the pressure in the intake tract is at 18 psi. What does the torque curve look like? afterall.... it is the torque that moves you ;) | ||
| J. Grande (Jay)
Intermediate Member Username: Jay Post Number: 1037 Registered: 10-2001 |
Chris just wondering is that 18lbs of boost on each turbo or 18lbs for both? | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 368 Registered: 3-2001 |
top | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 367 Registered: 3-2001 |
Jeff....running the risk of sounding rude...I am very curious as to what this modification has cost you. It sounds like a fantastic setup! Now...with my 355 Challenge Car..... | ||
| Chris Parr (Cmparrf40)
Member Username: Cmparrf40 Post Number: 547 Registered: 3-2002 |
Rob, yes you are correct. I had that ••••••• little brass valve on mine when I bought it, it was leaking and the most torque I could get was 368lbs, I went back to the factory setup and torque jumped to 431lbs. Your numbers are correct on boost, but I am running 18lbs with new Carobu chips. I have gone as far as I can go till I change fuel injection and I do not plan on doing that. You can go to about 650hp with a F40 before you really start screwing things up. Mine is reliable and scarey, just what I want! I have 2 friends with Norwood twin turbo's, one a boxer the othe a TR, both around 800hp, both cars are for sale and there are no takers. Great cars, Norwood does great work, but both of these cars are not that driveable....... gotta have a balance, sounds like the 348 in question is just about right! | ||
| Rob Schermerhorn (Rexrcr)
Junior Member Username: Rexrcr Post Number: 164 Registered: 11-2002 |
Chris, I'm pretty sure (really sure?) that the oem spec for F40 factory boost is 1.1 bar, about 16 psig or 30 psi absolute (14.7 + 16). The ecu will shut the injectors down at 22 psi, maybe that's where you got that number. Lot's of F40's have a little brass adjuster valve in place of the factory "shuttle" solenoid to tweek the boost. It's easy, dangerous if one does not add more fuel, and fun. Ferrari doesn't publish this number, so I can see how it can be misquoted. I have this information from FNA because I had to trouble shoot many for over and under boost conditions (more over than under). Plus, utilizing Mr. Norwood for information, I built a track F40 with huge Garret T3/4, carbon clutch, blah, blah. Nice power, love the cars. F40's are by far my favorite. | ||
| Mitchell L. Davidson (Jussumfastgi)
Member Username: Jussumfastgi Post Number: 396 Registered: 4-2002 |
Boost gains are not linear but suffer from diminishing returns due to heat. | ||
| Jeff Edison (Euro308guy)
Junior Member Username: Euro308guy Post Number: 195 Registered: 7-2002 |
interesting........ 20 lbs of boost and 478hp?! Wow, that's great! My 3.4 was built as a turbo motor. I'm not sure of the compression, but I assume I'll be able to find all the specs when I go through the records. I'm sure I could TRACK the car all day with no problem, I think the limit may be reached when the throttle is held wide open through all gears and then for over a minute straight after reaching 5th. I guess we gotta remember he's a Salt flats racer, thus the cautioning. After having driven the car for just a few days, I can't imagine doing that. Have you monitored egt rise and duration? How hot does it get, (egt), and how long have you had it at that temp? Since I gained about 50hp at the rear wheels from 10 psi up to 15 psi, I wonder if the increased gain would be linear, to say, 20psi? How much boost would I need to run, (along with the other aforementioned mods), to get to that level and beyond? I suppose time and desire shall tell. I'm guessing he can get a LOT more out of this engine than it makes now. As Rob said, it is a conservative, street setup. And I think he's not far off of his statement, (power wise). How often do you track the F-40? | ||
| Chris Parr (Cmparrf40)
Member Username: Cmparrf40 Post Number: 546 Registered: 3-2002 |
Jeff, my F40 is running 20lbs of boost, just under the stock factory setting of 22lbs. I can, and have run it all day at the track showing it no mercy, without a problem. My numbers are off a Dynojet dyno as of December 2002 | ||
| Jeff Edison (Euro308guy)
Junior Member Username: Euro308guy Post Number: 193 Registered: 7-2002 |
Ouch! OOOh, "let the man dream", gotta say that smarts! I wondered how far off Mr. Norwood might be. Standby for a few breif comments on him. I pulled out my coffee table book, "the complete Ferrari" to reference the F-40 to see what exactly are the power specs on this "super car". Is this twin turbo 348 really in it's company? Here's what the book says on p.222. "....and the base output is somewhere between 471 and 478 bhp, depending on who is giving the figures". Hmm, well my 3.4 liter twin turbo at 14.8 lbs or boost makes about 410-420 hp. "Firmly" I suppose may once again be strong describtion by Mr. Norwood. I'm sure he's dynoed more than one F-40. I'm not aware of the efficientcy of putting power to the rear wheels of the F-40 for a true rear wheel comparrison. I have no doubt that Chris's figures here might be accurate, (they do seem accurate to me based on the book), and I have no reason to doubt his word. If you've had the privledge of meeting this man, (Norwood), and having him actually talk to you, I think most would find him to be more than a little credible. So, Chris, how many pounds of boost do you run through your air/air intercoolers, (BTW, mine is a water to air), to gain this type of HP? Also, how long can you maintain this type of power without venturing into the danger zone of engine failure of some type. Mr. Norwood did mention this is in the POWER range, not performance. I wouldn't want to mislead anyone here. I'm not claiming the car will run down an F-40!! It is quite a bit heavier I'd guess. But it is also, quite a bit lighter on the wallet. Now for Mr. Norwood. If I was owning an F-40, I'd not be overly concerned about my 348 on the track, but you'd be well advised to beware his Testarosa TT's! The guy is a master tuner. I've become quite a fan. | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3356 Registered: 12-2000 |
Saw the car Friday and met Jeff. It's a very nice 348 with a very conservative set up. Nothing special about the twin turbos, but with the addition of a nice intercooler from Norwoods. I think the goal is to take it one step at a time. Just running 15 psi, like he said, there's much that can be done, but at what price in reliability and cost? Right now Jeff has a street reliable 348 that puts out 420 HP. Not F40, but 360 for sure and at a fraction of the price. You wouldn't believe how little he has in the entire thing. | ||
| Mitchell L. Davidson (Jussumfastgi)
Member Username: Jussumfastgi Post Number: 391 Registered: 4-2002 |
Lol, I know. Hence the "Not" at the end. Let the man dream. | ||
| Chris Parr (Cmparrf40)
Member Username: Cmparrf40 Post Number: 545 Registered: 3-2002 |
A stock F40 is around 420hp at the rear wheel, my F40 was dynoed at 482hp at the rear wheel. 70 to 132hp is a huge difference at the rear wheel! | ||
| Mitchell L. Davidson (Jussumfastgi)
Member Username: Jussumfastgi Post Number: 389 Registered: 4-2002 |
HE said 350 at wheels. That is quite near F40 per it's weight. Not | ||
| Chris Parr (Cmparrf40)
Member Username: Cmparrf40 Post Number: 544 Registered: 3-2002 |
Firmly in F40 Territory? At 350HP you are still a long way off and many dollars from F40 Territory, but you certainly have a damn fast 348! | ||
| Jeff Edison (Euro308guy)
Junior Member Username: Euro308guy Post Number: 191 Registered: 7-2002 |
ok, here are the #'s everyone has asked about. It was quite a change in expectations, but really came out for the best. I was told the car was about 400hp at the crank, (5lbs boost, not intercooled), when I drove it originally. When I got to the dyno with Bob Norwood, I found out it was actually about 350 hp at the crank 300 hp at the wheels, with 10 lbs boost, (last dyno results, non-intercooled). The car was very quick then, but what would it do now?! Bob recommended pumping up the boost to only about 15lbs. This in conjunction with the intercooler for protection would allow me to "beat on the car" quite a bit harder without damage, (ie burning a piston). Thats what we did. It was amazing to watch him load the car on the dyno and tune the Motec as he ran the car up to 7500 rpms. Now the car makes 350 hp at the rear wheels and about 400-420 at the crank. According to Bob, (how could you doubt this guy?), 550 or more is easily accessable at the wheels, this would require a few more steps: Up the fuel pressure Up the boost Change the injectors Completely re-map the fuel injection Better be careful of "long bursts" - even with the intercooler. His recommendation: "drive it like this for a while and see how you like it. The car is now faster than a 360 and firmly in F-40 territory" He's gotta be right. On the way home, I think I demo-ed it fairly well. See "8 hours of laughter" |