Foster382

I'm trying to find out if my injectors are 90# or not. The number on them is 5235306. I found a page on here saying their 90# https://www.thirdgen.org/forums/tbi/...-identify.html but are they 90# @13 or 30 psi? The tbi is from a 87 suburban plow truck so is the regulator

Ronny

iTrader: (1)

DC posted that. Suggesting they are same as "5231" a low pressure application. I once owned a pair of 7.4L high pressure injectors that are at 30 lbs or greater(?) FP. I believe were for 1994-1995 7.4L engines. Not sure of the number?

i BELIEVE THE oem # IS 17113081 AND 17113080 FOR THE 45 LBS at 30+ fp

Foster382

I'm thinking their not #90, before I installed my 350, my 305 used a 1/4 tank to work. Now with my 350 I use 1/4 take to AND from work. Talk about fuel economy!
I guess I'll have to look to see if there's a casting # on the regulator for the fuel pressure psi

Ronny

iTrader: (1)

??? I dont think casting # may help. I am not sure on that. I removed my stock FPR and used an aftermarket Aero. Maybe there is a part/ref # for regs? I recall my 30+ lb spring was orange. My 13 lb spring was green. My aftermarkets were bright steel color

xch3no2

Ok look, first there are NO 90# injectors available.

Anybody who calls them that is wrong or lying, period.

Sean had his injectors tested by Gordan @ 14psi hence the incorrect values.
Don't get me wrong DC is one of our good guys!
But,
I've seen the flow sheets to prove it.

Lets all stop using bad info here.
A link to a chart with mostly good information,
http://www.someotherplace.com/info/TBI_V8INJ.JPG

Richard was nice enough to to turn my data to jpeg, but I have not been able to justify #327's rated at 65# myself. The ones I have flowed are always up near or over 68#, I have Gordan test mine @ 13 psi. One day I'll get with Rich and ask him to straighten that out.

Look for your injector # on the citymaker site, it has a large cross reference.

No casting id that I am aware of on stock regulators, paint code?

Carry on.

Foster382

Then alright I'm fine if their 80# @13 psi. I needed to know so when I Install my regulator I know what to put Into my .bin tables. xch3no2, would you know how many # is made per psi on a regulator?

xch3no2

I can't really grasp the question behind that, pounds per square inch = psi.

Is there another way you can state the question? Keep in mind Immatard.

Also keep in mind these injectors can have a HUGE 10% variance from the low ones to the highest, one reason flow matching is popular.

Foster382

How many #'s will my injectors Increase by per psi of fuel pressure I set a regulator at.
No need to be a smartass. We all gotta start somewhere.

Ronny

iTrader: (1)

I have a calculator for the flow grams/lbs. I need inj size and fuel pressure. then the BPC value also needs CID.

Stock GM TBI regulator can be made adjustible but you are limited by spring. Typical is 12-13 maybe a couple more lbs. aftermarket offers one higher good for maybe 12-18 I forget (topdownsolutions). GM also had a high press application 30-35 lbs spring.

I believe the 80 lb inj(2506) has been found to be 75 lbs at 13lbs FP. Correct XCH????

Foster382

Well o got a few sets already 46# 55# and BBC injectors and a vrafpr that I may hook up to the 55# cause my regulator came off my print gt turbo. Min. Fp is 20psi on it

xch3no2

http://www.gtsparkplugs.com/InjectorSizeCalc.html

http://www.fuelinjector.citymaker.co...ester_TBI.html

dctrumpet

iTrader: (10)

Hey guys! Yes, my injectors are all done at WitchHunter. He tests them for me at 1bar (14.7psi).

Here's a good example:
5235206 flows 730cc/min @ 14.7psi
5235206 flows 686cc/min @ 13.0psi

That is technically a 65lb injector at 13psi. LOL Crazy isn't it? Who actually knows what pressure GM tested their injectors at and what solution did they test it with? Everyone says they know.... lol. GM's idea of "acceptable" pressure range was 9-13psi. If that's the case they may have tested their injectors at 10psi. That's the only way they could call a 5235206 injector a 55lb injector.

Gordon uses a fluid with the same specific gravity as gasoline. Thus, producing results taht would be almost identical to flow rates when they are installed in the vehicle.

My advice to ALL of my customers is to NOT focus on casting number, but focus on ACTUAL flow rates only. Based on what we know for sure (actual testing) then and ONLY then can you figure out what you will need fuel wise to support a particular build. SOme may disagree with me, but this is my 8th year doing this and Gordon just flow tested my 1000th TBI injector for me. I see the results and deal with the customers and we've had amazing success.

Another good example here... I just received (18 used) 5235206 injectors back from servicing. The lowest flowing injector was 715cc/min and the highest flowing was 765cc/min. These were at 14.7psi. Substantial difference in flow rates. Also, I have (28) brand new GM 5235206 injectors recently tested and their rates were 718cc/min minimum and 755cc/min max.

My advice is to have your injectors flow tested by a reputable source and make sure they include a flow-sheet. Well, a flow-sheet that makes sense lol.

Just a nugget of info here that really is hard to knock. Proof is in actual data and not suspect data.

Thanks guys!

Sean

dctrumpet

iTrader: (10)

My 17084304 and 5235231 injectors flow almost identically at 14.7psi. In fact, I have 17084304 injectors that flow more than 5235231. LOL. GM was absolutely amazing weren't they? LOL

Flow rates at 14.7psi
17084304 and 5235231 injectors range typically from 870cc/min to 900cc/min

So, this means those injectors are high 70lb to low 80lb per hour at 13psi.

Just stating what the data reveals.

freaky

http://diy-efi.org/gmecm/component_i...injectors.html

dctrumpet

iTrader: (10)

That data has been around forever. Where he got that info I have no clue.

Again, mine is based on actual data and real life application.

dctrumpet

iTrader: (10)

there are other injector servicing companies out there that use a different fluid for testing. Actual specific gravity of that fluid is much different than gasoline. Meaning flow rates are LOWER. This may be what GM used to test their injectors.

The reason for the use of the "other/different" fluid for testing is that it is MUCH cheaper to use so, more cost effective

kendalljmeyer

can someone tell me the part number for fuel injectors for a 1988 350 tbi out of a truck? i bought this engine to replace my blown 305 and am really lost. thanks

dctrumpet

iTrader: (10)

The 350 were 5235206 injectors.

thomas1976

Cool you are posting the actual flow numbers here