it should increase X per PSI of boost. anywhere from 6psi of fuel pressure per psi of boost up to 12-14 psi. usually injectors get angry around 90-100 psi of fuel pressure, the pressure of the fuel will make it hard to open and the spray pattern will get weird. also the stock fuel pump may not be able to keep up with the higher pressures. when was the last time you replaced your fuel filter? that will restrict fuel flow over time too.

an intercooler will help you immensely, that'll cool the charge and help with detonation. you still need to make sure there's enough fuel though. if you don't have a fuel pump then get one. then save for injectors and some kinda of engine management, I prefer the AEM EMS but there's also hondata, and e-manage.

hope that helps.

 

I currently have the fuel pump that came with the comptech kit. I just want my car to run like before, with no detonation. Its really frustrating that all of the sudden it decides to knock on me! If increasing the pressure doesnt work, I might have to go with a emanage, I heard that you dont need anything else besides an emanage, plug and play harness, and tuning. Am I right? I dont think I could afford aftermarket injectors right now.

I really appreciate all your help people!

 

a good tuner should be able to properly tune emanage.

I would just price out th emanage and the harness first, you may end up close to a used AEM EMS off the forums which gives you the benefit of being a true stand alone instead of a piggy back.

 

UPDATE:

So I installed the fuel pressure gauge, and it reads 42 psi with the line connected. I tried pinching the vaccum line without removing it, but there was no difference in fuel pressure. (?) I upped the psi to about 46 at idle, and there was no more knock in first gear, but some in second. So I increased the pressure to 50 psi at idle, and this gave me no knocking in first and second, with only a little in 3rd gear at high rpms. The car feels fine down low, and there is no difference in idle and no low speed bog. Interestingly, I feel it more torquey in the low end! It seems to have more power now, although Im scared I may be pushing the limits of the injectors. Tomorrow Im going to take the car to a dyno shop, and speak with my tuner about what he can do with the car as is, and if there is anything he can play with on the dyno (spark plug gap size, FMU, etc)... Do you think the car is ok with the pressure this high? It runs fine, but of course I cant tell if it is now too rich...

thanks for all your help in advance!

 

Ok well that helps, so you were at stock idle pressure, 43psi is stock, that means you were only getting up to about 70-75psi at 9k. I can tell you right now that was too lean. fuel pressure goes up about 30 psi from idle to wot redline fyi. so now at 50psi you should be in the 80psi range at redline, which is still too lean INMO. You could safely do another 10psi of pressure and be safe, maybe more. I ran 95+ at 8psi with stock injectors for 20k miles with little issue. I would add more fuel and save your money at the tuner, he isnt going to do anything for you that you cant do yourself.

 

Awesome! I will try that tomorrow and see what happens! Thank you so much for your help! I will check back tomorrow with an update!

 

Glad to help, Not sure what changed recently to cause this knocking but at least now we know you have room to try some things. It could be colder temps/winter etc that will cause this, or sometimes with some of these problems you just never really figure out the cause, but do manage to get them resolved, it can be annoying haha. Experience helps and that's what some of us can offer.

 

Your tuner as good as he may be is mistaken about this, you do not need any timing modifications at 7psi, or even 10psi. Turbo is a different story however. Yes your bottom end will feel boggy to make the afr's correct up top, thats the trade off and experienced by many of us when we had that set up so dont feel too discouraged, there is a solution and much less expensive one. I hate to see you blow a wad of cash if it will do you little good but to line your tuners pockets in this crappy economy.

If you want to fix your bottom end rich fueling, I suggested you get a inexpensive used vafc with a pnp harness from one of the members on the board, you will also be able to lower your vtec which is a great perk! You can get the complete set up for around $300. They work great for this task, I put 20k miles on that set up before no problem. If you want to give your tuner some money, have him tune the vafc for you since you cant check your afr, that unit is so easy to learn how to tune though that I would skip the tuner, invest another $300 on a working AEM wideband so you can tune your afr yourself, that's what I did. The tuner session you skipped will pay for this stuff.

The AEM EMS and Kpro are excellent units no question, but its a whole different game and one that you want to get the most use out of for the money invested, dont let someone talk you into these when your running 7psi and under, its a waste because you dont need but 20% of the features they offer at your level. Save that set up for when your running beyond 10psi