L67 injectors on L32 motor IFR help

[gambler87]

Ok question. I am going to be upgrading to 42# injectors, they have the older style clips. I got a set of clips and a known good set of older 97-03 L67 injectors. I soldered and heat shrunk the clips on and put in the older style injectors into my 04 comp g.

Now even using the 97-03 injector flow rate table or the 04 injector table I still see 10 to 1 afr on my wideband under quarter throttle. Any higher and it just pegs out super rich.

My question is has anyone else ever done this and got it to run good? And what should my injector table look like to make these work?

 

[BoostedPontiac]

I thought that L67 and L32 injectors flowed the same. It was just the connection that was different ev1 vs ev6.

the formula (old flow rate) / (new flow rate) = (some%)

36 / 42.5 = 0.8470

Therefore, 36 Lb/Hour injectors flow 84.70% of the flow of 42.5 Lb/Hour injectors. On that basis, you could multiply the IFR table for 36 Lb/Hour injectors by 84.70% to get the new value.

If so, your table would now look like this;

219--------------------185.493
216.5-----------------183.3755
213.49----------------180.82603
209.36----------------177.32792
206.51----------------174.91397
208.08----------------176.24376
207.78----------------175.98966
207.48----------------175.73556
207.23----------------175.52381
206.5-----------------174.9055
205.84----------------174.34648

This would be somewhat richer, but maybe a good starting point.

 

[CrazyGuy03]

Going from stock to 42s , I would take the stock table, and multiply by 1.25. they will get them close. You shouldn't have to touch any other table to get the injectors dialed in right.

Remember, injector ratings are at 43.5 PSI of fuel pressure (Typically done with a specific test fluid) The 3800 fuel system typically runs at 45+ PSI.

 

[gambler87]

I figured it all out on my own.<br />
<br />
All this info came off of witchhunter.com which tests and meters fuel injectors<br />
<br />

<br />
This is their test of a new L67 injector tested at 43.5psi<br />

<br />
This is their test of a new L32 injector tested at 43.5psi<br />

<br />
Then I had to take their test of cc/min and convert to lb/hr. For the L32 I got 33.3. For the L67 I got 33.7. This is using witchhunters conversion calculator<br />

<br />
Then I had to convert the pressure readings in 60psi flow instead of 43.5psi taking into account the 04+ fuel pressure and non return system. I got 39.1 lb/hr at 60psi for L32, and 39.6 at 60psi for the L67.<br />
<br />
Then I took 39.1 divided by 39.6 and got .987 which is 98.7%. Then took my stock IFR table for the 04 and multiplied it all by 98.7% and got my new table.<br />
<br />
Car runs awesome now

 

[CrazyGuy03]

Cool