limits of walbro 255 pump, 600hp
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I beleive, after just a few days of playing, i found the limit of my single walbro 255 fuel pump. I figured out how to log delivered flywheel torque into the trans, whick only works in direct with the converter locked, and can therefore calcullate horsepower from it, just like a dyno does. so, off i went. with some tuning to get things running ok, low timing, and not very stable boost pressures, i managed to get a decent log in 3rd gear. Well long story short, i am seeing a long line of 500+ hp and quite a few in the 550+ range. even had a couple over 600, with the highest of 628hp, but im not sure if that was in drive, so i wont count it.
Right now im sitting at a solid 550 crank hp, that is at about 8psi, and 5600rpm. The car starts to break up and go lean at that point, but the numbers are jumping anywhere from 30-50hp per 400 rpm increase depending on boost, when i let out of it. And my cam is good to about 6600rpm, soooo, i dont think 600whp is out of the question if i can get some more fuel in it.
Example, 8psi
RPM, 3600, 4000, 4400, 4800, 5200, 5600, 6000
HP, 394, 412, 454, 517, 543, 584, 593
That is an actual log, discredit it as you will, but i feel it is fairly accurate, as this formula has been dyno dested to be within 3-4%. Also makes perfect sense because that is all a walbro 255 is capable of.
Discuss, oh, and sorry about no pics, im working on it
Gary -
Well nice set up and good to see you are getting it tuned and ready for the season. I look forward to seeing it at the track.
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I find it tough to believe that you think on 8 psi out of an s475 you are making near 600 hp. Is .5 bar even on their compressor maps?
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well this isnt some shitty little 4 banger, this motor makes around 440hp n/a, so i dont see that being out of the question. Case in point, same cam as in my GTO, equal exhaust capabilities, and that made 363rwhp in the heat. That car had 18% drivetrain loss, so, thats 428 crank hp. This motor is more efficeint, bigger bore, 17ci bigger, better intake manifold, heads that flow 20cfm better. 440hp is easy. I know it sucks starting with a 150hp 4 cylinder and trying to make big power, but its just too easy with a 350+ci engine.
Gary -
And do you have dyno sheets to back up these claims? Or are you going off of some magical thought in your head?
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Grr;166097 wrote:
. I know it sucks starting with a 150hp 4 cylinder and trying to make big power, but its just too easy with a 350+ci engine.
Garyand gets how many miles to the gallon.
look at his teg for instance. That car is pretty damn fast and its a 4 banger Ibet if he drove it as a DD(not sureif he does or not) but i bet he would get over twice the mileage you do and still go as fast at the track:icon_thumleft:
Matt
92 Civic HB
JDM d15b w/14b@8psi
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krzydrftr93;166101 wrote:
and gets how many miles to the gallon.look at his teg for instance. That car is pretty damn fast and its a 4 banger Ibet if he drove it as a DD(not sureif he does or not) but i bet he would get over twice the mileage you do and still go as fast at the track:icon_thumleft:
Now hold on a minute. There are PLENTY of turbo V8 cars getting 25-30 mpg. Are you saying he is getting 50-60 mpg in his teg?
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I don't even know my mpg, never cared. I laid down 540 whp like 2 years ago and drove it home from Sioux Falls @ 33 mpg and some change.
Now as far as fuel pumps, I made 560 whp on a walbro 255 on stock wiring w/ 720cc fuel injectors at a base pressure of 38 psi. Now, was that the pump that ran out or the injectors? My vote is the injectors.
The thing about PSI vs. HP is that on average at low boost a turbo is going to make a maximum of 10 hp per lb of boost. This number seems to hold true to most turbos on most setups. Figure at 8 psi this is another 80 hp. If he's making 520 hp on the motor I don't see it being a very friendly motor towards forced induction.
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very true, it is dropping for sure, hell, the more i think about it, it might even be a walbro 307, thats a little weaker in the high psi ranges than a 340, but its been years since i bought the damn thing.
And magical thoughts? a 4l80E transmission has the ability to read input shaft torque, it isnt magic to turn a torque # into a HP number, every dyno in the world does it. And, there is no way to fudge the presented input torque, also the calculation is the same one used by every dyno produced, so if what the tranny in my car sees is magical, then i guess every dyno sheet is magical too. Look at any STS, rearmount system, on a stock car, say a LS1 camaro, dynos 320whp stock. STS on 8psi? if you cant get at least 420whp out of that, shoot yourself. thats a solid 100whp gain any day of the week, well a 100hp gain on my motor is AT LEAST 540 crank hp. Get a life.
On the other hand, there are so many turbo LS1 f-bodys and vettes that get over 20mpg, i wont even get into it.
Gary -
I beleive everyone was thinking you were refering to whp #'s, not crank.
FYI, I plan on making ~500 RWHP on a walbro 255 this year. It's not a standard walbro, it's a racetronix. I beleive it is modified to provide a higher fuel pressure. I firmly beleive I won't have any problem with making that (almost 600 crank).
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krzydrftr93;166101 wrote:
and gets how many miles to the gallon.look at his teg for instance. That car is pretty damn fast and its a 4 banger Ibet if he drove it as a DD(not sureif he does or not) but i bet he would get over twice the mileage you do and still go as fast at the track:icon_thumleft:
i dont believe he made this thread to compair who gets better gas millage, it seems alright to me, as for you go buy a geo and be happy
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So what is 540 crank HP to the wheels through a 4L80E slushbox? 90 hp less?
And I should probably shoot myself I've only made 311 HP per liter so far, and I am only on pace to make over 400 HP per liter this year. Man, imagine what us stupid 4 cylinder guys could do with 6 liters! Haha.
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integra_gsr98;166113 wrote:
So what is 540 crank HP to the wheels through a 4L80E slushbox? 90 hp less?And I should probably shoot myself I've only made 311 HP per liter so far, and I am only on pace to make over 400 HP per liter this year. Man, imagine what us stupid 4 cylinder guys could do with 6 liters! Haha.
Remember gsr horsepower means nothing if you just sit at the rev limiter all the way down the track.... i can see it now no traction ever... but did you see my sweet 400hp per liter..OMGHI2OH
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Grr:
- If I had rich parents that helped me mod my car, that would be sweet. I too wish I had rich parents.
- Rotarys could technically be treated as 2.6L motors due to their design.
Traction is difficult, but I guess we'll see what this year has in store. Chassis work is sweet.
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Can anyone barrow me their rich parents for a year? Please?
Oh dang, guess I will have to just pay for it myself.
Also, I beleive, and correct me if I am wrong, nicks cars has clocked a faster 1/4 mile time, which really is the only thing that matters....
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BTW, it is a walbro 307, that is sooooooo gay. Im actuall kinda pissed about it. On the buick board, they say 550hp with a 307, 640 hpwith a 340 i guess a nice new walbro 340 should be good for another 75hp than this shitty 307 with 40k miles on it. Damn it anyway.
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