I've read loads of the old threads on how much better the Bosch 3 injectors are compared to the Motec, but a LOT of time has passed since the Bosch 3s were released.

Are there any modern injectors that have even better atomization than the Bosch 3s that are available in physical and flow sizes that are appropriate for a 400-500hp TPI-style SBC (FIRST intake)?


All the really high-end injector companies have just insanely huge injectors now; all I need is a good 35ish lbs @ 3 bar injector, but fuel economy is definitely high on my list of goals and I'll take every minor improvement I can get.



Adam

 

I called Fuel Injector Connection today; here's the short answer:

The Gen 4 Bosch Injectors have a finer atomization in sizes > 24 lbs.

The Gen 4 Bosch Injectors have far better response times than the Gen 3s. The Gen 3s often have the holes enlarged by the injector companies which further decreases the response times on them; if you then also increase your fuel pressure beyond 3 bar, you're further degrading the already not-so-great response times.


You may need an EV1 adapter to use the Gen4 injectors; FIC includes them for you.

Adam

 

These guys make the finest atomizing injectors, but they don't support the physical sizes required for a TPI intake and they only sell BIG injectors for big power applications. They're also EXPENSIVE:


http://nostrumenergy.com/fuel-injectors.aspx



Adam

 

You still need to tune for them ( voltage offsets).
Do they provide this information ?
https://www.thirdgen.org/forums/diy-...or-sticky.html

 

Good question.

I know they do for their "Signature" series injectors; I'm sure hoping they do for all new injectors. (The Bosch Gen 4s I bought were brand new and unmodified, so Bosch should be able to provide this info, right?)



Adam

 

Good luck getting it from Bosch. I have heard they won’t reveal this information. The supplier might have it. Southbay has provided the 19,22#hr .

 

Additional details, for what it's worth: I'm running Holley EFI, so if I can get good data, I should be able to utilize it easily.


Adam

 

Ok, now you're freaking me out a bit... Contacting FIC...

I can't see why Bosch wouldn't share this information.

Unfortunately, I ordered the 36# hr injectors...



Adam

 

I’m not sure why Bosch won’t share the information. It might be to keep the aftermarket or black market copies from being made. Just a guess.

 

You know of anyone build a voltage regular circuit and installing it prior to the injectors so the timing doesn't need to be adjusted? (Seems like a possible hack, anyway.)


Adam

 

Wouldn’t the quad drive have a regulator built into it ?

 

Here's what FIC sent me.

Is this the entirety of what I need?

4.5
7.285745
5 7.169087
5.5 6.218478
6 3.962941
6.5 2.573279
7 1.939834
7.5 1.574168
8 1.309082
8.5 1.114422
9 0.954994
9.5 0.827989
10 0.725101
10.5 0.646214
11 0.573173
11.5 0.500671
12 0.435207
12.5 0.386359
13 0.339858
13.5 0.292894
14 0.24897
14.5 0.212892
15 0.176967
15.5 0.141236
16 0.108773
16.5 0.080887
17 0.054694
17.5 0.029539
18 0.011423

 

Looks like that’s what you need

 

Seriously, thanks for letting me know that I should ask for this info!

Adam

 

Sorry guys, but bosch makes injectors from 15-42lb that are unmodified. I know that for a fact because I have them in stock

 

Read it again. No one said, nor implied that unmodified Bosch injectors weren't available in that range. I think you're reading something that's not there.

My 36 lbs are brand new and unmodified.


What was stated was that injectors are often modified by having their holes enlarged and are then resold and that that process increase the latency further.


What was also said was that increasing the fuel pressure also increases the latency; both these things can take an already "meh" response time Bosch III and make it worse and a Bosch Gen 4 is going to have better response times.


Adam

 

I understand, however if they come in every size I'm confused as to why they would need to have the holes enlarged??
I'm sorry I guess I'm misunderstanding the point
Are you referring to the bosch lll's?