| Author | Message | ||
| BretM (Bretm)
Advanced Member Username: Bretm Post Number: 2799 Registered: 2-2001 |
I was just taking a guess at octane they might run so you guys would probably know more than me. I would be interested to find out how much advance they run though. F1 cars idle around 3000 rpm, so that is a good point in how much the sucking action must help the fuel delivery. On a street car at idle the fuel would probably just mist in the filter box for the most part. At work we have a 333 engine and drivetrain from a car that got wrecked a couple years ago. That engine looks so much like the F1 engine, at first glance it would be hard to tell them apart (obvious cylinder difference, but at a quick glance). I've never seen it with the filter box off though, I'm gonna have to check it out. Now that would be a sweet engine for the 308, take the sequential drive train and all. I think down the road I will do something like the 355 stacks are setup or stacks with individual plates, that would probably be best on the 308. I still have plenty of time to learn more though before I would make a switch from the stock plenum though. Paul did you swap your car to carbs yet? If so, how is it doing? | ||
| Ben Lobenstein 90 TR (Benjet)
Member Username: Benjet Post Number: 833 Registered: 1-2001 |
Here are my guesses... 1. Think about high RPM situations (way over 308 redline) you want air to move into the chamber with force and swirl (hence the reason for velocity stacks), if you put the injectors farther down the path of the air (and think about how MUCH fuel you would require to be delivered at 15k RPM) how much "swirl" disturbance that would be. 2. I thought F1 used 103 Octane, but I may be wrong. 3. Idle....what RPM does the F1 cars idle at? Whatever it is, think about the lenght of time they will spend with the car at idle during the course of one GP (or the life expectacy of an engine - they aren't re-used)....They idle in the pits and on the grid, not too many other times, a street car sits at idle at every stoplight. 4. Would have to agree with Ed "emissions and driveability". Maybe I'm way off base... -Ben P.S. Great pic. | ||
| Paul Sloan (Sloan83qv)
Member Username: Sloan83qv Post Number: 391 Registered: 3-2001 |
here's a photo of the ferrari V-10 without air box.  | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 393 Registered: 5-2001 |
Jet fuel is a lot closer to kerosene, heating fuel oil, and desiel fuel then it is to gasoline. I doubt the F1 guys are using jet fuel. | ||
| Hans E. Hansen (4re_gt4)
Member Username: 4re_gt4 Post Number: 339 Registered: 4-2002 |
FWIW - don't know the relevance - I was recently at a vintage car race. They had some old CanAm cars, many with small block Chevys. Some of the injection systems were as you describe: velocity stacks with a FI nozzle not actually above, but mounted high in the stack. Wondered about this myself. I'd guess that part throttle performance would be crappy. It takes some air velocity to properly mix the fuel, and with a small throttle opening, the air velocity near the top of the stack would be minimal. I have heard old racers say that these (Hilborn?) injection systems were only suitable on the race track just for that reason. | ||
| Dan B. (Dan_the_man)
New member Username: Dan_the_man Post Number: 38 Registered: 9-2002 |
I am not sure about the design of the intake systems on the F1's, so there may be more to it than what I am about to say, but.... The advantage to a dry intake system is that you can make sharper curves in the runners. This opens one up to making longer runners which increases mid range torque (thus production cars). I would suspect that the runners on the F1's are very short to aid in higher top end hp thus it would not suffer from the fuel "falling out" of the air. When fuel is mixed with the air at the beginning of the runner, then it has a tendancy to "fall out" of the air in a tight bend. this is due to the fuel being heavier. The 308 has a very short runner (the carb'd ones do anyway, and I would think that the Fuel injected ones do too) so you would be okay to run a wet system. fyi | ||
| BretM (Bretm)
Advanced Member Username: Bretm Post Number: 2797 Registered: 2-2001 |
I see, I wonder what octane they run. I think jet fuel is around 180 and at the track guys run like 110, so it's somewhere between there. I think it would probably make a mess on a street car and varnish everything, make the throttle stick, etc, but interesting nonetheless. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 2144 Registered: 2-2001 |
It may be because of the type fuel that they use. The biggest advantage of getting the injector close to the valves on a street engine is for emissions and driveability. It heats up faster there. This is also the reason for the old carb heater stoves from the exhaust manifolds to the air cleaner snorkels as well as the heated grids under the carb base plates that were used in years past. The greatest emissions occur during warm up and when the car is not running on todays cars. We now have heated oxygen sensors and more closed fuel systems to counteract those problems. | ||
| BretM (Bretm)
Advanced Member Username: Bretm Post Number: 2795 Registered: 2-2001 |
Alright, for all you tech/engineer guys I have a question which I have been pondering for about a month now when I dream of things I shouldn't do to the 308, but will for a quest in HP. How come the F1 engines all use a wet intake system? They have the injectors above the velocity stacks, actually above them with the tip of the nozzle not in the stack, put point at it maybe a centimeter or two above it. This is above the throttle plates obviously too. If they're using it then there are obviously advantages to it, but other than possibly a better mix of the air and fuel I can't really see why this is the case. Other racing is all moving into direct fuel injection (all those ALMS type prototype racers), so why is F1 moving the entire opposite direction with the injector on the complete other end of the intake system? Why don't they apply a wet intake system to a street car? And yes, I have already conjured up how I could make a system like this on the 308 when I swap to velocity stacks in a couple years, but I don't know it would be beneficial, plus it would be a lot of work. Can someone enlighten me. |