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Confused on Speed Density pish posh..

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Old Jul 2, 2009 | 09:08 PM
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Default Confused on Speed Density pish posh..

Clearly SD is the way to go with high HP turbo cars. Im building my kit right now, shooting for mid 700s just to get my feet wet before i build my bigger cubes motor.

Now my question is...

I used to have a NA setup with a **** ton of mods and more importantly with a SLP 85mm MAF on a LS1edit tune, 98PCM/wiring on a 6 speed. Soo now that im going turbo... I sell the SLP MAF and buy what exactly>??? I know i need the GM 2bar MAP, which will only limit me to 14.7PSI before its out of its range and i need to buy BIG STUFF (maybe next year ). Which is fine, because on my 88mm it should yeild mid 700s as planned. Obviously i need 60+ lb injectors, BUT i cannot fire up my car and drive on the trailer to my tuner with all this changed on the NA ls1edit tuned 98 PCM. Sorry to repeat, but i want to know exactly what i need to buy so i can at least fire it up and have the PCM reading the larger injectors, 2bar MAP, and the lack of a MAF...

Thanks!
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Old Jul 2, 2009 | 10:10 PM
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Yeah you need 2 bar map and SD tune in place to start or go anywhere. Not familiar with ls1edit run hptuners. For hptuners you pretty much just install the 2bar operating system and car started up. Set it for the injectors and that was that.
You can leave maf in there temporarily or buy a tube I got a nice shiny 3.5 by 4 inch tube off ebay works prefectly.
So you may have to push it on the trailer to get it to the tuner.Or drive it there before you install the new map sensor and delete the maf. And if your ls1edit don't work with 2bar or 3bar you will need a different tuning program. You don't need big stuff 3 . Again not sure about ls1edit but many cars have gone plenty fast with hptuners.
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Old Jul 3, 2009 | 02:12 AM
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As mentioned above HP Tuners has a 3 bar operating system. That's what I plan on using for my build. Along with some 85 or 100 lb/hr high impedance injectors so the factory computer will run them.
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Old Jul 3, 2009 | 07:52 AM
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Originally Posted by TurboAv
Along with some 85 or 100 lb/hr high impedance injectors so the factory computer will run them.
It has been my experience that it is much easier to tune large low impedance injectors with a converter box than high impedance injectors. Also 100# low impedance injectors with a converter box is cheaper than than 75# high impedance injectors by themselves.
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Old Jul 3, 2009 | 03:18 PM
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If you just want to start it so you can get it on the trailer, leave the std injectors and map sensor in place, no need for a MAF should still run good enough to trailer.

Then swap out injectors and Map sensor at your tuners,,,,,,,,,,,,,,,

Just upgrade your PCM to a 99 and go to a 2 or 3 bar operating system, no need for an aftermarket PCM unless your shooting for huge HP.
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Old Jul 3, 2009 | 03:39 PM
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Originally Posted by ls1290
It has been my experience that it is much easier to tune large low impedance injectors with a converter box than high impedance injectors. Also 100# low impedance injectors with a converter box is cheaper than than 75# high impedance injectors by themselves.
No way...

Find a set of 100's and a driver for $400 bucks: http://fuelinjectorconnection.com/sh...d&productId=19

Those tune EASILY and since rated at 43.5psi, they flow quite a bit more than 75.

I tuned a set on a stock car when they first came out and have used them in 4-5 FI setups since.

Last edited by Frost; Jul 3, 2009 at 11:28 PM.
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Old Jul 3, 2009 | 04:39 PM
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I'm confused... It won't even start?!

Not trying to hijack the thread sorry but I have an 02 camaro forged 347, t76, tial 44mm waste gate with the large blue spring, 317 heads, fast 92, 3 bar, maf delete, 224 242 612 609 116 114 cam, 96# injectors, converter box. dual pumps, blah blah blah... Can I not even start it? I know it won't idle right because it'll be running off of a n/a maf 228/232 cam only tune and won't have a maf but it will start and run correct? I wanted to dial in stuff like fuel pressure with my regulator and check for leaks and get oil in all the passages and what not before I trailer it to the tuner so I know it won't have any bugs

Thanks

Last edited by 02anti_vnm; Jul 3, 2009 at 05:09 PM.
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Old Jul 3, 2009 | 05:04 PM
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Originally Posted by 02anti_vnm
I'm confused... It won't even start?!

Not trying to hijack the thread sorry but I have an 02 camaro forged 347 t76 tial waste 44mm waste gate with the large blue spring 317 heads fast 92 3 bar maf delete 224 242 612 609 116 114 cam 96# injectors converter box dual pumps blah blah blah... Can I not even start it? I know it won't idle right because it'll be running off of a n/a maf 228/232 cam only tune and won't have a maf but it will start and run correct? I wanted to dial in stuff like fuel pressure with my regulator and check for leaks and get oil in all the passages and what not before I trailer it to the tuner so I know it won't have any bugs

Thanks
no do not start the car unless it is tuned for the injectors you will wash out the clyinders
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Old Jul 3, 2009 | 05:36 PM
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What's that mean? And if I can't start it how do I get the oil system primed? The engine has been sitting for like a month and a half since I put it together
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Old Jul 3, 2009 | 06:22 PM
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Originally Posted by Frost
No way...

Find a set of 100's and a driver for $400 bucks: http://fuelinjectorconnection.com/sh...&productId=125

Those tune EASILY and since rated at 43.5psi, they flow quite a bit more than 75.

I tuned a set on a stock car when they first came out and have used them in 4-5 FI setups since.
Holy **** you just save me some money I owe u a beer cheers
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Old Jul 3, 2009 | 06:31 PM
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Originally Posted by 02anti_vnm
What's that mean? And if I can't start it how do I get the oil system primed? The engine has been sitting for like a month and a half since I put it together
You can prime it by disconecting the fuel system power and turning the motor over with the starter holding it for 10 seconds at a time. You should see 1-5psi on the oil guage. I dont think it wil;l be enough to fill the turbo but u have to try and see. Becareful not to overheat the starter I woud do it about three times and wait 30 mins and try again if you see no oil but you will. Also breakin is critical on a new motor if you wash the bores with gas then kiss your rings good by. That thing will burn oil like a mother fker. My dumbass friend did that on a tsp stroker, Put 60# injectors on and drove 30 miles to get tuned needless to say he spun a bearing because the oil was full of gas and after the teardown all the rings where scorn and the bore was close to being complete destroyed. Also he was **** because it putdown 380 hp and ran like a slug. tuner told him to break in the motor and bring it back But it went down that night after he got it tuned lol
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Old Jul 3, 2009 | 08:17 PM
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Originally Posted by Frost
Find a set of 100's and a driver for $400 bucks: http://fuelinjectorconnection.com/sh...&productId=125
Those look like about a third of the size of the 75# RC injectors I had. Those look like the size of 36ish one They again I did buy them when they first came out for $800ish.
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Old Jul 3, 2009 | 09:58 PM
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I wouldn't use those 75's because they say they are modified injectors. Probably drilled out 60's. Here are the new Siemens 83# ones I'm thinking of using. $400 for 8 also.

http://hinsonsupercars.com/p-1033-si...35&PID=3193633
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Old Jul 3, 2009 | 10:01 PM
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Originally Posted by ls1290
Those look like about a third of the size of the 75# RC injectors I had. Those look like the size of 36ish one They again I did buy them when they first came out for $800ish.
and HALF the size of my $600 79# ers. I might just get another set of these and run 79lb ers then at X boost, run the 75's
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Old Jul 3, 2009 | 11:29 PM
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Originally Posted by TurboAv
I wouldn't use those 75's because they say they are modified injectors. Probably drilled out 60's. Here are the new Siemens 83# ones I'm thinking of using. $400 for 8 also.

http://hinsonsupercars.com/p-1033-si...35&PID=3193633
Woops thanks for pointing that out... the 83's were the ones I was actually looking for there.

http://fuelinjectorconnection.com/sh...d&productId=19
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Old Jul 4, 2009 | 02:01 AM
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at what size do injectors or the PCM require this "converter box"? and will the box work with the stock PCM?
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Old Jul 4, 2009 | 02:19 AM
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Stock injectors are high impedance. This means the ohm reading on them is about 12-14. Low impedance injectors are around 3-4. In order for your stock ecu to fire low impedance injectors you would use a injector driver box that would go between the ecu and injectors. AEM makes one as well as the Acceloronics Versafueler. With the advent of good high flow high impedance injectors all but the most crazy builds should be able to get rid of the driver box and just run some 83lb/hr siemens high impedance injectors. Fraser at Speed Inc even said he had some 100lb/hr injectors that worked great.
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Old Jul 4, 2009 | 02:24 AM
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Some of the old problems I read about with the high flow high impedance injectors was that were hard to tune and didn't flow in a linear fashion. From speaking with people that have used the new Siemens 83's that doesn't seem to be an issue any more. It will be another month or so until I use them on my build and get some real world first hand observations though
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Old Jul 4, 2009 | 11:27 AM
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Originally Posted by TurboAv
Some of the old problems I read about with the high flow high impedance injectors was that were hard to tune and didn't flow in a linear fashion. From speaking with people that have used the new Siemens 83's that doesn't seem to be an issue any more. It will be another month or so until I use them on my build and get some real world first hand observations though
Thanks for the input. It's nice to know a little more about the crazy amount of money I spent on my 79's vs saving money and getting the 83's
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Old Jul 4, 2009 | 07:43 PM
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Most modern high impedance injectors will perform and tune easier than the more dated low impedance injectors.

That doesnt include the RC range of high impedance....they arent so nice.
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