dykz34

Hi all,

Normally I wouldn't post this type of thread in this section, however I feel that the majority of people that could help me are in this section! I have installed a brand new set of Siemens 80# injectors in my 2000 FRC and am having trouble getting them dialed in. I used the "injectors.xls" spreadsheet from the HPT forum to determine the proper values to enter into the IFR vs MAP table and made the necessary changes. Loaded the bin into the PCM and fired up the car. It really struggled to start and ran really lean (1.25 lambda - 25%). I tried to scale the VE table by that amount but was then greeted with the lovely Reduced Engine Power message on the maiden voyage down the block (I assume you cannot scale the VE by that much...). My second try was to remove 25% from the IFR vs MAP table and that got me to a pretty good spot, idles nice and drives nice but I feel that I am going about tuning the car in a "non-proper" way by scaling that table. Does anyone have any tips on where I should focus my efforts? I've read a lot about a Short Pulse Adder table, any advice on that? Is that the correct place to add 25% more fuel?

Current mods: LG Street LTs, no cats, LS6 intake, ported LS1 TB, 4" intake, Open Loop Speed Density 2-bar OS, & E85

Thanks everyone!
Dave

user_name

You are going to have to scale the VE and IFR to avoid the reduced power mode. Do them both at the same time. With the stock cam there is no way those injectors are giving you idle issues. What do the VE #'s look like up near peak boost?

dykz34

When you say scale both VE and IFR at the same time do you mean to split the needed change evenly across both tables? In other words, if I'm off 20% do I scale each one 10%?

I have not done a scan at WOT for fear of blowing it up.

Thanks!
Dave

user_name

You scale the IFR by say 20% so the pcm thinks the injectors are smaller. Then you scale the VE by 20% to get the same amount of fuel.

Milan

I disagree.

I had nothing but problem with the stock cam and SD80's in my car. Some people say they have gotten those things to idle properly, but I don't believe them. There is a huge difference between idling like stock and good enough.

I spent hours trying to get those injectors dialed in and I got them pretty good but not perfect. PM me your email and I can look at your tune and share what ended up working for me.

PS I ended up selling them and getting ID1000's and haven't looked back. Having proper injector data is the only way to go. I guess it all depends on if you want your car to be perfect or good enough. My ID's hit 1.00 lambda at idle like a boss @ 850 rpm, if I change the VE table they actually respond with the same amount of change, something my SD80's never did.

user_name

You couldn't do it so it can't be done?



Doesn't seem to need any help idling here when blipping the throttle. This is with a 218/228 cam on a 115lsa.

dykz34

Let's say I'm 20% off all over: can I make a global change in the IFR by 20% then fine tune the rest from VE? In other words, change the IFR table once and be done.

dykz34

A slight degradation in idle quality is livable. I'm more worried about predictable fueling... I command leaner, go lean... I command richer, go rich. I really appreciate your offer to look at my tune. I will send it tonight from my laptop. Thanks!

user_name

Yes. You can do that. Careful about the advice you get online. The hardest part about tuning is learning to ignore the people with little experience or first hand knowledge. Good luck.

TracyRR

My tuner, geoff with engine power systems, tuned my 80's to idle great but he did say that it had to have a boost referenced fuel pressure regulator so he was able to lower my fuel pressure enough at idle. My 370" has a small cam also, 218/230. Best of luck

AZZ-KIKR

I have 80's in my new setup and it idles great however, I did not tune it. I will leave that for someone with the experience in that area.

dykz34

Excellent. I have already made the global IFR change and will now work on the VE.

Thanks!

corvette8189

running 80's here

Corvette-Chris

My car runs perfect with 80's

Milan

I'm not saying it can't be done. I'm saying it's a pain in the *** and it's never going to be 100% like stock.

Can you post a log of your car idling at a normal RPM at stoich, and then another one with the AC on?

If I see that I will eat my words.

If the injector data was close (or correct) he wouldn't need to scale his IFR or VE tables. There is no reason to be hitting Reduced Power Mode when cruising around the block.

OP let me ask you this: Is your FPR vacuum/boost referenced? Also those 80 lb injectors are more like 89 lbs at our fuel pressure, what do you have in the 0 column under the IFR table?

Milan

If your commanded lambda (or AFR) is 20% off all over you should only have to scale the VE table, not the IFR table, again provided your injectors are set up correctly.

If the injectors aren't responding properly to a 20% change in VE then the problem is incorrect injector data.

You shouldn't need to scale tables on the pre-2005 cars.

user_name

I'm not going to go do idle logs just for this, but if I find one on my other laptop I'll post up

AC was probably on in this old vid since it was may.



Not sure why you use the phrase "like stock." If you can drive it and never have to adjust your driving due to its idle characteristics that is a perfect idle. I have that with these injectors and this cam. 825/875 idle speeds. It was a decent bit of work, but nothing like others I have done.

I'm honestly wondering what you did to make it idle poorly with the stock cam. It is just so damn docile unless you have lowered the speed to 400-500 for some reason.

He's going to have to scale to avoid reduced power with the power he's going to make.

user_name

Your car is the only 1 you have tuned, isn't it?

OP: You need to scale the VE AND IFR in a 2-3 bar hpt gen3 pcm application once you start making enough power that the boosted VE cells need to be well over 100 to hit your correct AFR with the correct IFR values that you computed.

I'm telling you this is the place to get bad info. Try the HPT forums and double check yourself with HPT support to avoid costly mistakes.

Milan

Maybe you know something I don't...but it doesn't even seem like he is boosted.

He definitely is not going to make more power than you or I on E85 and only 80 lb injectors. I've never had to scale my IFR tables back. P1514 on the other hand is a different story.

Milan

Please do post on the HPT forums. I will be shocked if anyone on there tells you to scale your IFR table due to improper injector data.

My car maybe be the only GM I have tuned with HPtuners but it is far from the first car that I have tuned.