L67 injectors on L32 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 the only difference in l67/l32 injector was ev1 and ev6

anyways the new IFR should be calculated by:

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 than the example above, but maybe a good starting point. This is on stock fuel pressure.

Edit: http://www.rceng.com/technical.htm That is a good site for formulas. As far as modifying the table you're just scaling based on injector as long as you don't change the FP. The big problem I see as to why these tables don't work perfectly is no one is considering the fuel pressure. We have different fuel pumps, age of the stock fuel system, filter conditions.

The Lucas 42.5's supply 42.5 at 40# of fuel pressure per the spec sheet.

 

[SgtMarshal]

L67 and L32 have the same IFR because they both use a 36 lb injector. when switching to the 42.5 lb injectors you divide 42.5 by 36 or something like that to get about .847. if you are using hp tuners your IFR will be higher because the pcm will pulse the injectors less times with a higher number. if you are using dhp it is the opposite.

 

[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