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25psi here I come!!!

i have run 35 psi on 1000cc's.... the 23 its set at now is almost an insult to the setup.
 

FYI guys: please do some calculations before you buy injectors. It takes a VERY built motor to handle the 35-40 psi of boost that you can run with 1600's, plus dual fuelpumps. Don't just upgrade to the largest thing you can buy, and figure "I don't ever want to have to upgrade again". /ubbthreads/images/graemlins/banghead.gif All injectors have a certain range of linearity, and although the FIC Blue Max injectors aren't as bad as the Bosch 1600's, you are still going to have a lot more trouble getting them tuned in than a more practical size, like 1150-1250cc. I constantly have to point out to people that the injectors they are thinking of buying will not even make it to 60% duty before their Walbro 255 pump is out of fuel:
click
Its very simple to calculate: take your injector flow, correct it for the base fuel pressure you run, and multiply X .24 to convert to liters/hour:
1650cc @ 37psi = 1522cc
1522cc X .24 = 365 liters/hour
At 30 psi of boost, the fuelpump will be required to supply fuel at 67 psi. Looking at the chart, even the best Walbro 255 HP pump, REWIRED, can only supply ~210 liters/hour, which is only 59% duty cycle of those 1650's!
Most customers end up buying the Blue Max 1150cc to 1250cc injectors from me instead, which will still do 30 lbs of boost easily on E85. The other advantage is you can still switch back to gas with them and have decent driveability. Bragging rights don't mean anything if your car runs like crap.
 

Brianawd

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Joined
Apr 18, 2005
Messages
2,117
Location
Portland OR,
Quote:
Most customers end up buying the Blue Max 1150cc to 1250cc injectors from me instead, which will still do 30 lbs of boost easily on E85. The other advantage is you can still switch back to gas with them and have decent driveability. Bragging rights don't mean anything if your car runs like crap.



What size turbo are we talking about? I am almost maxed on my 1600cc injectors on e85 at 30-32psi on a FP3052.
Also most all my friends here in the NW are seeing a max of 550-600awhp on 1600cc injectors and e85.
 

My 1000's work good, although 35psi wa sonly for 1 dyno pull and was the absolute top end of the fuel setup I have. The Megasquirt helps with the drivability. I just dont see how you could use 1600cc injectors on a street car unless its a rotary.

I know my turbo is a SBR GT14BB, and at 35psi I put 519 to the wheels. In order to do that reasonably safely, I need more fuel pump, I am running a rewired 255 with 6an lines from the pump to the rail.
 

Quoting Brianawd:
Quote:
Most customers end up buying the Blue Max 1150cc to 1250cc injectors from me instead, which will still do 30 lbs of boost easily on E85. The other advantage is you can still switch back to gas with them and have decent driveability. Bragging rights don't mean anything if your car runs like crap.



What size turbo are we talking about? I am almost maxed on my 1600cc injectors on e85 at 30-32psi on a FP3052.
Also most all my friends here in the NW are seeing a max of 550-600awhp on 1600cc injectors and e85.



Also remember how much more fuel (and therefore injectors) E85 takes. Mine is on race gas @ 35psi, pump gas @ 23 psi.
 

Brianawd

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Joined
Apr 18, 2005
Messages
2,117
Location
Portland OR,
Quote:
Also remember how much more fuel (and therefore injectors) E85 takes. Mine is on race gas @ 35psi, pump gas @ 23 psi.



I was not talking to you /ubbthreads/images/graemlins/dunno.gif. I also think I know what it takes to run e85
 

curtis

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Joined
May 4, 2003
Messages
11,892
Location
Clarksville TN
Also since Jeff jumped in.....Fuel pumps.

Compare fuel pumps not at just there advertised numbers but where they'll be with your regulator under boost. Takes some searching and research but you don't want a lean condition to trash a bank account worth of parts. Lots of times bigger is only bigger at a set n/a flow pressure under a rising rate they go to crap. Pressure may be there but no volume. Think of your house most city water systems are at 55psi now compare a 1/2 inch copper line with a globe/twist valve to a 3/4 inch with a ball valve. You'll flow enough water to peel paint with a larger volume.

Now my two cents this dual walbro stuff started long before the internet, dsms and supras etc. I actually wedged two in my mustang back in like 93 or 94. I had to build the assembly then install the normal set up in about 5 pieces and then secure all the bolts and hoses in the tank. Mustangs tanks have a hole about 1/2 inch wider than the pump. Then everything was golden for a few months, then one day on Ft Campbell in an intersection it died. Was getting some fuel just not enough. Had to drop the tank with about 10 gallons in it and remove both pumps and install just the one and go on home. What happened the internal check valve went out on the newer pump. They were both 155's, back then that was the big upgrade. Anyway I ordered the vortech t-rex inline to remove the big vortech sticker to find a part number, was really pissed to find out the thing was 68 dollars at autozone.


Now since I told you the story now is why it happened. If you have two pumps. You might have a 1 in a million chance of both pumps flowing perfect matching pressures and volumes 2% of the time..
If pump (A) is a 255 hp pump but flowing 260lph at 12.0 volts and 40 psi
Pump (B) is a 255 hp but flowing 258 lph might be at 11.97 volts and 39.5 psi due to wiring, machine tolerances of the gerotor pump design etc. Lots of variables going on here. Which means all the time Pump (A) has a differential pressure against pump (B) with a factory built in check valve means that a higher pressure and flow is closing the check valve in B and you now have a false since of security you think the two pumps are kicking above 500 but maybe hurting themselves to the point that your not even getting the flow of one. Another varible is flow of fluid in the lines. How many of these actually run a t fitting pressing against each other then fitting at a right angle to the pumps. I would say most.

MY verdict buy a 255 or better for the tank and a surge tank or reservoir set-up and a big inline going forward. You can wire in a hobbs switch to the rail that will cut the pumps off when pressure drops below 30psi etc so if the in tank or inline dies. Wire in indicator lights for voltage drops, etc remember the hobbs switch will have to have a timer or a toggle switch or it will never come on. I'm actually going to start research in a few weeks for mine. I bought a cell with a intank and a bosch but also have a SX 18201 that will support 1300 carbed or 700 fuel injected HP. I personally think its over kill for me but they do look crazy hanging from under the car. I've been looking for something else for a while now. Auto Zone has a book behind the counter that has a cross reference for every fuel pump known to man. It covers flow rates pressures, manufacturers and also there numbers as well as year make and model of the vehicle. VW rabbits have big units if I remember , volvo turbo station wagons and a few other odd balls all have big in lines that can easily cover 600 hp for less than 100 bucks. When I start and find some info I'll post links.
Rant over. Flame on if you want but any well designed fuild power set ups will not run two pumps parallel. If you want parallel run two pumps two complete sets of fuel lines twin filters and regulators and have one circuit with two injectors and the other with two. Actually this is a really cheap upgrade finding a Galnt n the junkyard is easy vr4 lines are a little different than a n/a car but two supplies and two returns from the factory will flow almost as much as a -8 AN. Big problem is having two separate regulators, no you couldn't connect them there that would be the a same as connecting in the rear to one line still detrimental to the pumps. Have it designed in the wiring if one dies they both die and the car shuts of instead of dragging two dry and melt them, remember fuel makes HP but also cools pistons....Think EGT temp and then think of the melt point of aluminum. /ubbthreads/images/graemlins/jawdrop.gif
 
Last edited:

gvr4ever

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Joined
Aug 6, 2002
Messages
6,191
Location
central Indiana
Holy blown head gasket batman. Really though, what does it take to run 25psi? I'm scared to push 18-20psi on my poor stock engine.
 

turbowop

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Joined
Apr 29, 2001
Messages
11,971
Location
Yakima, WA
All it takes is a good tune. I run 30psi on pump/meth everytime I take 1051 out of the garage, with a stock 136k mile engine. The only thing mine has is a metal headgasket and ARP headstuds.
 

I got one too

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Apr 1, 2004
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114
Location
San Diego, CA
The reason I purchased 1650cc was so that I would have enough injector when I go fp3052 or 65. At the moment the car has a fully built motor and it's being fed by a fp18g. I agree, I should have gotten 1150 or 1250, but that 'buy big' syndrome got me. I just got back from tuning and it was a b*tch, even for the old Haltech to control them 1650's. I'll be spending the weekend trying to tame it, so we'll see. If anything, I might just have to put these up for sale and pick up some 1150 or 1250.

The car is running on e85 and with my 720's it maxed out around 17-19psi by 8500. 25psi, is what I'm aiming for initially with the bigger injectors, but hoping for 30psi or as much as the turbo will do.

I did push that turbo to 25psi on 100 octane race gas and it scared the sh*t out of me. So I can't wait to tune it for 25psi on e85 and hit the tracks again.

Crap, if 1150 or 1250 can do 30psi on e85 with this turbo, I might just have to get those. /ubbthreads/images/graemlins/banghead.gif
 
Last edited:

Brianawd

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Apr 18, 2005
Messages
2,117
Location
Portland OR,
Quote:
The reason I purchased 1650cc was so that I would have enough injector when I go fp3052 or 65. At the moment the car has a fully built motor and it's being fed by a fp18g. I agree, I should have gotten 1150 or 1250, but that 'buy big' syndrome got me. I just got back from tuning and it was a b*tch, even for the old Haltech to control them 1650's. I'll be spending the weekend trying to tame it, so we'll see. If anything, I might just have to put these up for sale and pick up some 1150 or 1250.

The car is running on e85 and with my 720's it maxed out around 17-19psi by 8500. 25psi, is what I'm aiming for initially with the bigger injectors, but hoping for 30psi or as much as the turbo will do.

I did push that turbo to 25psi on 100 octane race gas and it scared the sh*t out of me. So I can't wait to tune it for 25psi on e85 and hit the tracks again.

Crap, if 1150 or 1250 can do 30psi on e85 with this turbo, I might just have to get those.




You really should not have any problem tuning those injectors on e85. But you are also using a Haltech. On e85 1600cc injectors tune easy. The only thing I see with my car and the 1600 is a small little stubble at low low rpms. We are talking parking lot speeds. So some of that could be a mix of the injectors and the twin disc clutch.
 

Quoting Brianawd:
I am almost maxed on my 1600cc injectors on e85 at 30-32psi on a FP3052.
Also most all my friends here in the NW are seeing a max of 550-600awhp on 1600cc injectors and e85.



Only 30-32psi seems a bit soon to be running out of fuel. What base fuel pressure are you running? Are you sure the rest of your fuel system is up to the task, providing enough volume? According to RC's calculator, 1600cc injectors @ 43.5 base pressure, 100% duty, with a VERY conservative .85 BSFC can make 713 crank HP:
RC Calculator
The true BSFC for E85 is probably closer to .80, but I can't get a definitive answer on that. At .80 you should be able to make 757 crank HP.
Lowering the base fuel pressure to 36 psi, and only 90% duty on the injectors, yields 623 crank HP, which is probably about where you're at.
But, anyway, the real point of my post was that:
1) you don't need 1600cc injectors for 25 psi, and most guys either aren't going to spend the money to properly build their motor to handle that much power, or don't want to risk running it because of the additional wear on the motor. For most of the guys on here, their GVR-4 is their daily driver, so reliability and driveability are also important.
2) 1600cc injectors are useless if you aren't going to also make the investment in a complete fuel system overhaul: double pumps, heavier fuel lines, new rail, etc. Once you start flowing >200 liters/hour those things become a necessity . If you know you are never going to spend the time or money to make the necessary upgrades later, you should avoid the tuning and driveability issues and get injectors closer to what you actually need.
 

381gvr4

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Nov 5, 2007
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Location
Wakefield, RI/Meriden, CT
^^^ Jeff I pesonally feel lucky to have you as such a great resource and being so open to passing on your knowledge. Big thanks for all your info and my ecu setup!
 

Quoting Brianawd:
Quote:
Also remember how much more fuel (and therefore injectors) E85 takes. Mine is on race gas @ 35psi, pump gas @ 23 psi.



I was not talking to you /ubbthreads/images/graemlins/dunno.gif. I also think I know what it takes to run e85



I was just pointing it out in the case some people did not know, not a personal question against your knowledge.
 
Last edited by a moderator:

I got one too

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Apr 1, 2004
Messages
114
Location
San Diego, CA
I agree, the 1650cc's are overkill for my current setup, but it's what I decided on and I'll just have to work with it. From the math, 1150's would've been perfect for my current setup.

I was able to tame the thing a bit. I dropped the fuel pressure from 43psi to 37psi, it's a bit more controllable now. Maybe I'll try lower.
 
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