Best BIN for runing 1.5 L 4 cylinder

[EagleMark]

Some of these pictures make me almost want to put a carb intake back on my 240Z, and run some modified flat top carbs I just got today.... almost.

Your just bored cause your car is done and running good, not to mention one of the coolest conversions ever done! You need another car... I have a 7747 truck, LT1 car and finishing a 16197427 conversion so I have everthing covered except I need a turbo or supercharged car to play with!

I looked at the 2.8 and 3.1 injectors and they are the big size injector that will not fit my adapter. The LeMans injector might be the best choice. I think what I need is a 700 series injector to fit the adapter.
When I change the BPC what are the other required changes? BPC vs Vacuum, etc?
The bore is 2.9 and stroke is 3.44. Almost the stroke of a 350. I have heard these were tractor engines before they were MG engines.

Oh. I see the injectors are differant... we'll wait and see what 1project2mqany has to say, or go back and read his first recomendation since he's been in this boat before.

BTW SWEET distributor conversion! I did this on an IH engine about 10 years ago and have made many since then.
http://www.gearhead-efi.com/Fuel-Inj...BI-Conversions

[EagleMark]

What is the size of injector you have?

[POZE]

It's 59 lbs hr from an S-10 2.5

[1project2many]

Yeah, the "old" generation of TBI injectors are a different size and won't fit the adapter you've got. You're right: The injector you need comes from a model 700 TBI or from the truck TBI with governor. If your fuel pump will handle it, buy the 454 injector and run it at 20 psi. If there are any doubts about the pump or if changing fuel pressure is going to be a challenge, buy the LeMans injector. Delphi part no for the 454 injector is FJ10485 and for the Lemans is FJ10040. I'd expect to pay $40-$50 for the 454 injector and at least double that for the LeMans injector.

I'd start by setting just the BPC and going from there. I believe you'll find the VE values will need adjusting again because you had the wrong injector constant to begin with. I usually scale the BPC based on the changes to engine size and injector flow. New displacement / old displacement * constant, new flow / old flow * constant. If you multiply the current constant by .438 it should be close enough.

That's a very large stroke. You might find yourself pulling a bunch of timing

[EagleMark]

Hmmm? That comes out to BPW of 75 at 13 PSI, which is pretty low... I don't know if that is beyond what the ECM is capable of? Also would support 100HP if that engine is close to that?

I know that a stock TBI engine runs so much better at 13 PSI then within GM specs of 9 to 13... higher pressure does atomize fuel better. Need to look at min air adjust too! Just enough throttle opening so IAC has some control over idle. IAC count of 20ish is good...

[EagleMark]

I've seen those small injectors on a big block TBI base in a 366 industrial engine.

[RobertISaar]

BPC can be set anywhere from 1 to 255 and it will still work as intended.

i'm a fan of the higher pressure route.

[1project2many]

Holley sells an injector pod for the small injectors to mount in the pickup truck TB. Folks work real hard to get a couple of extra MM of throttle diameter in there then leave those honkin' big injectors hanging over the bore on top. I'd go with the small ones myself. Tried finding the part nos for the small 366/427 injectors but not much luck. I dunno why I don't have them saved here.

BPW can go small, but it's good to make sure injector can deliver small PW correctly. A timing light aimed at the injector is another good way to make sure the injector is working correctly. I wouldn't expect trouble with these injectors in this application, especially if the injector pressure can be dialed down.

[POZE]

Excel says BPC of 106 to run the LeMans 42# injector on my engine. I have a 55HP engine.
If I change the BPC to 106 from 134 in the stock bin, does BPC Vs Vacuum and BPC Multiplier Vs MAT need to be changed the same percentage?

[Six_Shooter]

Your just bored cause your car is done and running good, not to mention one of the coolest conversions ever done! You need another car... I have a 7747 truck, LT1 car and finishing a 16197427 conversion so I have everthing covered except I need a turbo or supercharged car to play with!

Believe me, I have MORE than enough projects on the go...

Are we looking for larger injector or a smaller injector?

Can the 700 series injector not be adjusted like the larger TBI injectors? It's been a while since I've looked at one.

[EagleMark]

Excel says BPC of 106 to run the LeMans 42# injector on my engine. I have a 55HP engine.
If I change the BPC to 106 from 134 in the stock bin, does BPC Vs Vacuum and BPC Multiplier Vs MAT need to be changed the same percentage?

Looking at all the paremeters with BPC they are all multipliers so no. Except for "Base Pulse Constant Vs. Vacuum" seems to be BPC numbers used to cover idle and decel. Nothing for 50 to 100 KPA MAP.

Since Robert says the BPC can be adjusted low and everyone likes higher pressure, you may want to add a little pressure to just 14-15 and do your calculations. How are you controling fuel presure? Since no TBI unit?

[EagleMark]

Tried finding the part nos for the small 366/427 injectors but not much luck. I dunno why I don't have them saved here.
.

Would you send me the injector numbers and lbs pr/hr for those single injectors you do have? I will add them to the list.

[1project2many]

Excel says BPC of 106 to run the LeMans 42# injector on my engine.

It does? Then let me double check my math. I was falling asleep as I typed and I've determined by the results of several assignments when I was in college, my brain refuses to do math correctly when I'm asleep.

The 1.5 engine is 60% the displacement of the 2.5 but the 42# injector flows less than the original 2.5 injector. Yep... the scalar should be .77 which would give an injector constant of 104. It's very typical in GM land for injector size and injector constant to disagree slightly so I always scale the OE constant rather than calculate it from scratch.

Can the 700 series injector not be adjusted like the larger TBI injectors? It's been a while since I've looked at one.

The injector will respond the same way to pressure changes. That's how I was able to use four TBI injectors in my Cavalier PFI engine.

[POZE]

Mark, you are the master of distributor mods. The injector I have is Delphi # FJ10043 59 lbs hr and purple plastic screen frame.
Fuel pump is Carter P5001 external and Mallory 4307M regulator. I did most of the work on this car 3-4 years ago and now I have began to question some of the setup. I played with the fuel pump bucket idea back then but did the pump the easy way using the external carter. The tank mod for the pump bucket that I saw on the forum was done very nice.

[EagleMark]

That P 5001 TBI pump will flow the small amount of fuel you need to about 20+PSI. If you need more PSI you need the P 5000 for TPI. I've used both many times. Excellent pumps. Little noisy...

Never used an external regulater though? Should be 3/8th feed and 5/16 return... could be smaller on your application.