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Doonsuka
Samba Member
Joined: November 16, 2008
Posts: 5
Location: AZ
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 Posted: Sun Nov 16, 2008 10:44 pm Post subject: turbo adjustment fuel psi per pound of boost? |
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| Hey guys I am new to the turbo world and a have a question. I just had a solid 1915 with a single blow through del 40, and an electric pump (no lack of fuel for sure). Right now I am running 5 lbs of boost, and I want to turn up the boost to 8-10lbs. I am told the pressure regulator I am using is boost sensitive but I am not sure if it is adjusted or working right. How much fuel psi to boost lbs should I be running? How can I tell if I am running lean on a turbo motor? When under a load on the last motor, the carb would flood, until the turbo spooled, but when reved it sound mean! So I adjusted the regulator (it's boost sensitive ya know) and my next trip to the dunes I droped a valve. I dont know if that had anything to do with it or not but I dont like these kind of expensive lessons, and I really want to be able to do all the work myself. Any info you guys are willing to give will be greatly appriciated by this noob! |
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Matt Cramer
Samba Member
Joined: October 17, 2008
Posts: 86
Location: Covington, GA
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| Posted: Mon Nov 17, 2008 11:12 am Post subject: |
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It should add one pound of fuel pressure for every one pound of boost.
There's a couple ways to tell if you are running lean. The older way to do this is to read plugs, but the most accurate way to see your air/fuel ratio is with a wideband air/fuel ratio gauge. These read if you are rich or lean directly using a sensor in the exhaust. You'd probably want to be reading in the 11:1's under boost when you run that much boost.
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Matt at DIYAutoTune.com
Megasquirt EFI, wideband O2 sensor displays, injectors, and more |
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Doonsuka
Samba Member
Joined: November 16, 2008
Posts: 5
Location: AZ
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| Posted: Mon Nov 17, 2008 5:13 pm Post subject: |
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| Matt Cramer wrote: |
It should add one pound of fuel pressure for every one pound of boost.
There's a couple ways to tell if you are running lean. The older way to do this is to read plugs, but the most accurate way to see your air/fuel ratio is with a wideband air/fuel ratio gauge. These read if you are rich or lean directly using a sensor in the exhaust. You'd probably want to be reading in the 11:1's under boost when you run that much boost. |
Cool so I just set my fuel pressure to keep the motor good at the bottom say like 5 psi on the fuel, but when I am at 10 pounds of boost I should be at 15 pounds of fuel? Correct? |
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VdanielW
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Joined: May 06, 2008
Posts: 446
Location: indio, ca
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| Posted: Mon Nov 17, 2008 6:40 pm Post subject: |
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| What fuel pump are you running? |
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Doonsuka
Samba Member
Joined: November 16, 2008
Posts: 5
Location: AZ
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| Posted: Mon Nov 17, 2008 7:48 pm Post subject: |
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| VdanielW wrote: |
| What fuel pump are you running? |
A Walbro! Is that similar to a Walmart, or is it par? The guy that build my motor, told me with 10 lbs of boost it should make about 230 hp. I am having my close ratio swing built righ now it will be ready to instal this weekend. MSD 6 off road with rev box, Protronics flame thrower, ilo points, blaster coil, 8mm plug wires. forged crank, H-Beam robs, Engle 110 turbo cam, autocraft roller rockers (I think 1.25), forged pistons, 043 heads, dual valve springs. I got the meat now all I need is the potatos to complete the meal. Is there a cheaper broadband guage I might be able to get my hands on?
Last edited by Doonsuka on Mon Nov 17, 2008 8:17 pm; edited 2 times in total |
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seabeebuggy
Samba Member
Joined: October 03, 2005
Posts: 2395
Location: NM, CA, UT and now NV
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| Posted: Mon Nov 17, 2008 8:08 pm Post subject: |
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What you need to know is how much fuel pressure you pump has. say it is 20 lbs. you then can go about 18 lbs max boost. Boost regulators are basicly on or off. you set the regulator to the needs of the carb for off boost. the regulator will do the rest.
Other things you need to know is , AFR. If you don't your on a short trip to burning the engine.
Are you using larger Needle and seats? Boost needs a good flow of fuel or you can go lean.
What of any retard set up do you have or are you locked out at 24*
Also if you turn the boost up you really need to have race fuel until you know your AFR's are good. If you don't it can be ugly.
PM me if you want more help.
_________________
Seabee turbo buggy build
(Quote Runslikeapenguin said)
so to everyone else whos not a retarded butt pirate marine with an tacky ugly ass car covered in auto zone bolt and stick on s**t. (end quote)
A better place to talk offroad |
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seabeebuggy
Samba Member
Joined: October 03, 2005
Posts: 2395
Location: NM, CA, UT and now NV
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| Posted: Mon Nov 17, 2008 8:13 pm Post subject: |
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| Doonsuka wrote: |
| VdanielW wrote: |
| What fuel pump are you running? |
A Walbro! Is that similar to a Walmart, or is it par? The guy that build my motor, told me with 10 lbs of boost it should make about 230 hp. I am having my close ratio swing built righ now it will be ready to instal this weekend. MSD 6 off road with rev box, Protronics flame thrower, ilo points, blaster coil, 8mm plug wires. forged crank, H-Beam robs, Engle 110 turbo cam, autocraft roller rockers (I think 1.25), forged pistons, 043 heads, dual valve springs. I got the meat now all I need is the potatos to complete the meal. Is there a cheaper broadband guage I might be able to get my hands on? |
A close ratio is not what you want for a turbo engine. It will still spool but you will loose out on some really good power with the smaller gears.
_________________
Seabee turbo buggy build
(Quote Runslikeapenguin said)
so to everyone else whos not a retarded butt pirate marine with an tacky ugly ass car covered in auto zone bolt and stick on s**t. (end quote)
A better place to talk offroad |
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Doonsuka
Samba Member
Joined: November 16, 2008
Posts: 5
Location: AZ
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| Posted: Mon Nov 17, 2008 8:18 pm Post subject: |
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| Malpassi fuel pressure regulator boost sensitive, turbonetics waste gate. |
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Matt Cramer
Samba Member
Joined: October 17, 2008
Posts: 86
Location: Covington, GA
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| Posted: Tue Nov 18, 2008 8:56 am Post subject: |
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| Doonsuka wrote: |
| Cool so I just set my fuel pressure to keep the motor good at the bottom say like 5 psi on the fuel, but when I am at 10 pounds of boost I should be at 15 pounds of fuel? Correct? |
If the regulator is plumbed up correctly, that is what it will do. The fuel pressure is pretty straightforward; jetting the carb can be another story.
_________________
Matt at DIYAutoTune.com
Megasquirt EFI, wideband O2 sensor displays, injectors, and more |
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Doonsuka
Samba Member
Joined: November 16, 2008
Posts: 5
Location: AZ
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| Posted: Wed Nov 19, 2008 8:45 pm Post subject: |
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| seabeebuggy wrote: |
| Doonsuka wrote: |
| VdanielW wrote: |
| What fuel pump are you running? |
A Walbro! Is that similar to a Walmart, or is it par? The guy that build my motor, told me with 10 lbs of boost it should make about 230 hp. I am having my close ratio swing built righ now it will be ready to instal this weekend. MSD 6 off road with rev box, Protronics flame thrower, ilo points, blaster coil, 8mm plug wires. forged crank, H-Beam robs, Engle 110 turbo cam, autocraft roller rockers (I think 1.25), forged pistons, 043 heads, dual valve springs. I got the meat now all I need is the potatos to complete the meal. Is there a cheaper broadband guage I might be able to get my hands on? |
A close ratio is not what you want for a turbo engine. It will still spool but you will loose out on some really good power with the smaller gears. |
Well I will mostly run in the dunes, so I need that bottom end gearing to be short. With my last tranny I was constantly on the main shaft running in 2nd or first. Now I will be able to run on in 2nd and 3rd, to evenly distrubute the power ans wear. My gears were so far apart I could barley even climb comp out at glamis on 5 lbs. but with 10 lbs, I had no prob in 1st and 2nd with the front wheels in the air, but as soon as I tried to get third I ended up going all the way back to 1st, due to loss of momentum, and drastic drop in the RPM's. |
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