Well what are the facts? None of you race on road courses where you are 100% on the loud pedal for more than 10 seconds. In that 10 seconds you will have broken the law in all 50 states. A 10lb NOS bottle will give you about 3 mins iirc of full boost. A simple NOS setup will give you 150hp with no engine damage. Flip one switch to arm the system. Press pedal GO FAST! Hobb switch fuel pressure as a failsafe. RPM switch NOS on as a failsafe. This way nothing go Boom! A large D cylinder of NOS in your garage costs little and lasts forever. You can transfer NOD from the big tank to the little tank for FREE by freezing the 10lb small bottle while leaving the big tank and room temp. NOS will flow down the temp gradient. No need for expensive NOS pump.
Well put 150 shot in the 550 and show us how it's done fatboy. What you a failing to understand Chubba is we don't want only 3 minutes of extra power, we want the extra power ALL THE time, and without the chance of it grenading the engine. Yeah NOS works, but we aren't going to use it. And yeah it does grenade engines. There are plenty of videos on YouTube of engines blowing up squeezing the laughing gas.
My 550 has 500hp. I don't need anymore. You blow up engines when you are stupid. Years ago I ran NOS in my 308GTS carb car and my mondial cab QV car. On the 308 I ran NOS until I ran out of jets trying to be stupid and could not blow up the engine. The motor had many miles and I was going to rebuild it and ran crazy NOS to see what would happen. Upon teardown I found out I wasted my time the motor was perfect. A topend refresh was all it really needed. But that is OK you guys go ahead and beat your heads on the wall for 30HP and spend 1000 bucks doing it. I think you guys are dreaming thinking you can gain any real gains with no ECU reprogram. The years are ticking by and you could have your 150HP already if you did the NOS years ago like I said. How many years have passed since you did the custom headers? And you are still the local 348 HP leader. The others are still dreaming and you are dreaming just a little less. Oh NOS does not change your ability to pass smog either.
Okay, we will, or at least I will anyway. You just sit back, relax, sip on some moonshine, chew on some jerky with your seven remaining teeth, and let us worry about making more power. "Hold my beer. Y'all watch this."
I just finished measuring the volume of one side of the plenum top. I first measured out exactly 2 liters. Then I plugged up the plenum openings to isolate one side of the plenum. Next I poured in the measured water until the plenum was completely full. I measured the remaining water (175/ml) then subtracted it from the starting 2 liters = 1825/ml, or just over 1.8 liters. So both stock plenums would equal just over 3.6 liters (3650ml). From what I understand, which ain't much, for n/a plenum size you want at least 1&1/2 times the volume of the engine. Since our engines are 3.4L we want a plenum volume of 5.1L, or 2.5L per side if we stick with a dual plenum design. In a nutshell we are short 1.45L of total plenum volume. The engine is choked off.
The volume is critically depemdent on the area and length of the throat from the air filter to the plenum. The combination of the plenum volume plus the velocity stack volume compared to the mass of air in the throat from the air filter to the 'critical volume' determines over shich RPM band the intake system resonates and adds power. Given the 348 has 2 sets of intakes (unlike most V8s) you should consider the power band to be determined by one side of the intake system being fed by one side of the throat system. The cross over valve between the plenums broadens the RPM band on the lower end of the RPM band. In general (first order only) when you open up the throat (like Ernies throttle bodies mod) you move the power band up the RPM scale unless you also make the plenum volume proportionately larger.
Measured the intake runner length, from the bottom of the flange to the edge of the bell mouth, and it came in at 7 5/16". But you want total runner length including the intake port of the head, which I haven't measured yet. At this point I'm gonna guess the port length is 2 1/2". That would put the runner length at about 9.8". I ran some numbers and that would tune the runners to the 4th harmonic between 7000-7800rpm, with the peak benefit right in the 7200rpm area. When I dyno'd my car that is the exact range I was making maximum power. I was making 300hhp from 6900rpm all the way out to the rev limiter at 7750rpm, with a brief peak RIGHT AT 7200rpm of 305hhp. So in my opinion the math adds up. The best power is made when the runners are tuned to the 3rd, and ideally the 2nd harmonic. But the problem is the tuned harmonics are dependent on the rpm of the engine in addition to the length of the runner. The length the stock intake runners are, the 348 would have to spin up to 9200rpm to hit the 3rd harmonic, and an ASTRONOMICAL 12,700rpm before it would get to the 2nd harmonics sweet spot. So it's obvious they were designed to fit under the deck lid, and not for making max power. It's amazing what sleeping at a Holiday Inn Express can do. In a nut shell, there IS power left on the table. The question is, how are we gonna tap into it? Or at least those of us that ACTUALLY DO modifications and not just bench race.
I find it kind of interesting FBB pushing the "juice" as if he is on it all day and... Well, enough said. I ain't gonna juice the car, so forgetaboutit, fat boy. Right now we just wanna find out what more air will give us on the top end. And who said no one was going to do an ECU mod?! Buddy, it this all works out, we are gonna have to do at least a piggyback system. Maybe...
The ecu tuning will be that last thing I tackle. I wanna find as much "bolt on" power as I can before I start fiddling with ecu tuning. Why? Because each time you change something you have to go in and retune, and tuning time is not cheap. So I would rather have all the mods finished AND THEN get it tuned. That way I only have to pay for the tuning once.
Hey Cholo, here's that intake in action. [ame=http://www.youtube.com/watch?v=xMehJ0QruN4&feature=youtube_gdata_player]Golen Engine 502ci LSx Make 824hp and 744 ft lbs - YouTube[/ame]
Which is why you are developing the most expensive way possible. you are thinking in parts, add headers, add tb, add intake, fix ecu. You gotta do the empirical math, build it, and test it as a system. Ya'll best bone up on y'er helmholtz resonance...or you could just buy a faster car.
You have been crowing about that for years. So Chubba, tell me, where does the Helmholtz resonance need to be for the 348 to pick up some extra power? If you would be so kinda as to help us calculate that it would be a great help. Figure it out for the air filter box, as that needs a re-design. Thanks.
Oh No...I'm not that smart. I just bought a faster car and continue to race trying to improve the driver.
I don't know how many times I have to say it to ya fat boy, but Helmhotlz resonance is not the reason for doing this. HR only occurs once or twice in an engine's operating range where valve timing is not variable like in our cars, so it makes no sense to chase it down. Moreover, HR only gives you a small boost in intake charge, but not enough, in my opinion to chase the wave. In a boosted car, it does make more sense because the benefit is multiplied by the amount of boost you are running, which is why the Porsche Turbo incorporates an intake expansion chamber to capitalize on it. Also, the new Ferrari 12-cylinder engine likewise uses expansion chambers attached to the plenum to do about the same thing, however, with variable valve timing they can actually tune the motor to receive the benefit in a more predicatable and repeatable fashion. Such is not the case with our engines, even with ECU tuning. What we ARE chasing is a more efficient intake system to see if the stock one is robbing the engine of efficiency and power. This is the complement of upgrading the exhaust side with replacement pipes, mufflers, cats and headers. So far in our quest, we have done all the bottom end stuff that is legal and the work, costs and results have been posted for all to see, even the stuff that doesn't work. Which is a he11 of a lot more than other people do. Now we are looking to the same for the top end of the engine. We have discussed air filters, MAFs, throttle bodies and intake runner porting and polishing. Now we are at the point where we are wondering if an intake system that brings in more air can get us more power. Seems like a natural extension of our work. An engine is just an air pump. It's efficiency is measured in power output and something called volumetric efficiency which is just a measure of how much air volume gets pumped through it during a measurable interval. Unfortunately, I don't know what our engines are rated at, but it's probably not among the higher ratios, but is likely much higher than a normal street car V-8. We will see if we can get more efficiency and hence, more power. Who knows? We are not going to NOS our engines because we are not 20-year old rice racers trying to get our 20-year old Integras down the drag strip faster, or imitate some schlocky Vin Diesel movie (no offense, Vin, but your F&F series is juvenile ). I personally just want to see what is possible like I have done with every car I have ever owned. It's fun and it is not that expensive. Besides, fat boy, I have never wrecked a race car and sold it off for parts. That had to cost you a few buckets of wings! So, I'd think twice about tossing a wet blanket on our threads. To each his own poison. No, I am not going to juice my engine.
I personally would toss the factory injection set-up and go with an infinitely tunable aftermarket system as a first step. Motec, haltec, etc, there are a few to choose from. Once you have that squared away, tuning is much easier and cheaper to accomplish. Are any of you running such a set-up? Now that you have the brains of the car up and working, now you work the brawn. Swap intakes, exhaust manifold, play with cam timing, index your plugs, play with different thermostats, different temp sensors etc. You should be able to almost tune the thing in your garage at home, with a 4 gas and a lap top. It sound very expensive how you guys are going about it.
OK, so between us, Vince and I have 3 348s including a challenge car on a Motec, ported 348 TBs, ported and polished intake runners, expanded plenums, Goth exhaust, a Haltec, a Roush "blueprinted" motor and a set of 355 TBs adapted to a 348 motor. I guess it's time for us to do some wrenchin' and see how we can bastardize one of these cars into a hotrod makin' some conventional analog horsepower. I'm just sayin'...
I think you should put the 355 ITBson the 358. Everything you need a was already done to your car, and already has the tunable ecu, so no need to shop a new one. Only thing you're gonna need is 355 air boxes. The 358 is the perfect car for the ITBs in my opinion, I was talking to Cholo about that earlier today.
I don't remember "cheap" and Ferrari ever being used in the same sentence. Well, before this sentence. And, with all due respect to tkabowski, you don't need a pro for that one.
Whoa!!! Never said anything about it being cheap! Nothing is cheap when playing around with these things. Maybe I should have said "cost effective".
