Need Engine Work Opinions/Expertise, Quite Important

[Sayajin]

Hey guys. If you have been reading my past posts then you know that I have a somewhat serious engine oil leak that I need to fix soon. (I have been told my multiple mechanics that there is no danger to the car, just make sure I keep oil in it) However, engine work is like the only thing that I cant do myself or with the help of a friend, so I will be taking it to a shop to get fixed. Meaning I will be paying labor(replacing front cover which of course comes with new oil pump). So I want to get everything out of this one labor cost that I can. So here is what I plan on upgrading at the same time (btw, I am running a Buscher Stage 3 Shortblock, I also have a SAFC):

272/272 HKS Cams
720-750 Injectors
2nd Gen Lifters
and of course new timing belt and front cover with oil pump
(and before anyone says get the kit, Buscher's dont have balance shafts)

While doing these upgrades I have a few questions for you guys.

1. Can I install those big ass injectors without a bigger fuel pump? I didnt think so but I heard that you can. (I am getting a Supra one)
2. If I need to get the fuel pump, do I HAVE to get a AVPC for it? (I read somewhere that with those injectors and big fuel pump I need one in order to make my car run properly. I mean like the pump will push too much into the engine flooding it if I dont? Sorry I am not sure exactly. (this is the big thing)

The reason I ask this is because money is quite tight, but I want to fix the problem ASAP. So If I didint need the Pump I would just install it myself later. However, it will be a while before I can afford a $1000 AVPC so that will kinda put a stop to all this if I HAVE to have one. Then once I do the engine work I plan to get around to doing all of my other mods once my cash is right.

Thanks a lot guys and I would really appreciate the answers to these questions, it is really important to me to get the issues with this engine fixed. I just dont have another 2-3grand to drop into it ASAP if I have to get all of these things at the same time. So it would be nice if I can wait on the fuel pump and AVPC. (the AVPC is the big thing, I suppose a fuel pump is relatively cheap if I have to buy it) Thanks.

*edit* I also wanted to add in that my goal is to hit the low 10sec range and that I plan to add on the FP3065 in the future once I get everything straightned out and get my necessary supporting mods. Thought this may make a difference in peoples suggestions. Thanks.


-Sayajin

 

[psychlow]

1) The stock pump will run those injectors, but not at anywhere near their maximum output range. You'll want to stay at a very stock-ish power level until the pump is upgraded. Also, is there any reason you're getting the Supra pump over the Walbro 255LPH? Are you really going to exceed what the 255LPH will give you?

2) I think you're confusing AVPC with AFPR. Larger pumps overrun the stock Fuel Pressure Regulator (FPR), which causes a non-linear fuel curve. Under normal operation, your fuel pressure regulator runs at a base pressure of 37PSI with no vacuum, and then it raises 1:1 with boost (with vacuum applied, it'll be less than the 37PSI). When the stock FPR is overrun, the increased pressure is what you get until you boost above the pressure that's overrunning the FPR.

For example:
Say your pump is overrun your FPR to 50PSI. At that point, 50PSI is the LOWEST the FPR will go. So, from full vacuum to zero vacuum to 13PSI of boost, you're still going to be at 50PSI of fuel. From 13PSI up, you'll get a 1:1 increase.

The ECU expects the 37PSI base pressure and a FPR that's not being overrun. So, it injects fuel based on this, which ends up inaccurate.

So, at idle, you'll run REALLY rich. At deceleration in gear, you'll run EXTREMELY rich. At zero vac to 10PSI, you're still pretty rich to a little rich. Then around 13PSI, things even out to where they should be.

You can tune this out with a SAFC to a point, but it's very hard, and any time a change is made to your setup, you'll have to start over. You're also at the pump's mercy - if, for some reason it starts to get less voltage (maybe due to a stereo or the A/C kicking on), it'll start to flow less, and you'll run leaner in the areas you're overrunning the FPR.

Another question - is there a reason you need the 720cc injectors? What are your power goals? If you have an AFPR, you can adjust your base pressure to ~60PSI with 660s, and run 550BHP with room to spare.

I know this was long, but I hope this helps!

 

[ZyklonBZombie]

i would get a walboro fuel pump over the supra tt one ... flows almost as good but a hellavu lot cheaper.

supra tt fp - $250.00 +
walboro 255lph - $100.00-125.00 tops

 

[Sayajin]

1) The stock pump will run those injectors, but not at anywhere near their maximum output range. You'll want to stay at a very stock-ish power level until the pump is upgraded. Also, is there any reason you're getting the Supra pump over the Walbro 255LPH? Are you really going to exceed what the 255LPH will give you?

Well The supra one has a higher flow rate and is much quiter. Not in the immediate future but soon yea I do plan to hopefully run a setup that might exceed the Walbro pump. However it wouldnt be for a while. Also I had heard/read that the supra is a better all around pump then the walbro and is worth the extra cash. Is this not the case? Also so I will be able to run the injectors just not a full power, but my car will still run fine for a few weeks before I upgrade the pump and what not?

) I think you're confusing AVPC with AFPR

Ahh that might be exactly what I am doing. I read your post and here is my question. So if I dont upgrade the pump at the same time I get the injectors, do I still need an AFPR? (I would definetly get one if I need it, its much to tedious to try to do it all with the SAFC) If I didint need it until I get the new pump, I would definetly just wait till I got the new pump to get an AFPR, or should I get it with the new injectors even if I dont get a bigger pump?

Another question - is there a reason you need the 720cc injectors? What are your power goals? If you have an AFPR, you can adjust your base pressure to ~60PSI with 660s, and run 550BHP with room to spare.

Well I am not sure of a specific power goal as far as HP goes, however I want to be able to run 10s in the future, as well as I want to put the FP3065 on here which is a 650HP bolt on. I thought that with the 10sec goal those injectors would best suit me, as well as I would need them with the FP3065,however if this is not the case please let me know.

Also let me know what you guys think about the fuel pump. Thanks a lot.

*edit* and one more question, would I also have to get new cam gears to go with the HKS Cams?


-Sayajin

 

[psychlow]

Originally posted by Sayajin
Also I had heard/read that the supra is a better all around pump then the walbro and is worth the extra cash. Is this not the case? Also so I will be able to run the injectors just not a full power, but my car will still run fine for a few weeks before I upgrade the pump and what not?

If you're planning to run 10's then yes, the Supra pump is a better selection than the Walbro. You may want to start looking at other fuel system upgrades as well, including running new/larger lines from the fuel pump forward. One of the largest restrictions of the stock fuel system is the filter and its banjo bolt - if you convert to a higher-flow, standard-type filter with AN fittings, you'll be much better off. It'll cost some bucks, but you're not going to want to skimp with the goal you're shooting for.

And yes, your car should run without too many problems on the 720's once you tune them correctly with the SAFC. Due to the fact that your fuel pressure will still be 37PSI, you may have some issues with fuel atomization with injectors that large, but it should still run.

Ahh that might be exactly what I am doing. I read your post and here is my question. So if I dont upgrade the pump at the same time I get the injectors, do I still need an AFPR?

It could be helpful to raise your base fuel pressure so you can get better fuel atomization with larger injectors, but no, it is not necessary.

Well I am not sure of a specific power goal as far as HP goes, however I want to be able to run 10s in the future, as well as I want to put the FP3065 on here which is a 650HP bolt on. I thought that with the 10sec goal those injectors would best suit me, as well as I would need them with the FP3065,however if this is not the case please let me know.

For those goals and power levels, you actually may need larger than 720cc injectors, if you are looking to max out the FP3065. 720cc injectors will support a maximum of around 675HP if you run your base fuel pressure at 65PSI, (which is pretty high.)

*edit* and one more question, would I also have to get new cam gears to go with the HKS Cams?

No. Actually, one of the benefits of HKS over other companies is that they degree their cams to match stock cam gear timing. If you get cams from another company, you may need adjustable cam gears in order to get good gains from them.

See this thread for more information on cams than you probably want to read.

 

[Sayajin]

Thank you very much for all of your input. It is GREATLY appreciated. Also let me say that I am not one of those guys who thinks running 10s is as easy as sticking on a new turbo. I know it is quite difficult to do and most fail. However, that does not mean that i cant shoot for that. I also plan to be able to take a while to reach it. I also realize that I may fall short of it, however it never hurts to shoot for the moon as far as I am concerned. Also that is what I really want to do so why not strive for it? Just wanted to point that out as I know you get tired of newbie’s believing that.

For those goals and power levels, you actually may need larger than 720cc injectors, if you are looking to max out the FP3065. 720cc injectors will support a maximum of around 675HP if you run your base fuel pressure at 65PSI, (which is pretty high.)

Well what injectors would you suggest I get then? I thought I had done adequate research for my goals but it seems this was not the case. Thanks a lot.

Also I think I will do the pump and get an AFPR at the same time as I do the injectors and what not. Just because I will run so much better. I will probably wait to do the ECU chip and lines till I have more cash available. BTW, could you give me an approximate cost for the new fuel lines as well as the filter with AN fittings? Also is there a specific place you would recommend getting it from?

I assume that the fuel filter and lines is not something that I can do in my garage and I would need a pro to install these for me as well? Just wanted to find out so I can adequately plan my revenue.

Once again thank you very much for your help and input. It is truly appreciated.

 

[CanadianTSi]

Why do you want to install the Injectors now??? why not just wait till you actually need them?

 

[Sayajin]

The reason for this is becuase I am having some engine work done which I am unable to do myself. Therefore I have to pay someone labor to do it for me. And while I realize that a lot of the upgrades I can do myself, I figure why inconvenience myself if I can get someone else to do it for me for pretty much no cost? Also the engine work is not upgrading, its actually replacing parts and what not.


-Sayajin