Fuel options...

[jrocstar]

Re: Fuel options...

it is jsut a cam it will be fine to run stock i can pretty much guarantee it here is a little equation take your calculated hp at the crank and don''t lie here to make the numbers look cool take this and times it by your brake specific fuel consumption at wot and divide it by number of injectors and that gives you flow amount so figure 220 hp with a bsfc of say 40 divided by 6 injectors gives you a 14.6 lb/hr injector you wouldn't need the 19's until you were running 11.8 with forced induction bsfc for na is always lower than forced induction cars so quit worrying and just put the cam in

[tkoforpresident]

Re: Fuel options...

it is jsut a cam it will be fine to run stock i can pretty much guarantee it here is a little equation take your calculated hp at the crank and don''t lie here to make the numbers look cool take this and times it by your brake specific fuel consumption at wot and divide it by number of injectors and that gives you flow amount so figure 220 hp with a bsfc of say 40 divided by 6 injectors gives you a 14.6 lb/hr injector you wouldn't need the 19's until you were running 11.8 with forced induction bsfc for na is always lower than forced induction cars so quit worrying and just put the cam in

wow.

thanks :tup:


btw 220 is probably a little generous. :)

[nightrider2]

Re: Fuel options...

your numbers are wrong, I'm not really sure where you got those numbers but with my cam and flow rating I came up with 22.3...the maximum horsepower you can effectively achieve with 16lb/hr injectors is 165 on a V6. with the stock top end flow numbers, taking into consideration his 1.6 rockers and how they affect the cam profile, I came up with 17.9. 3.8s have 18s. I had some similar work done on my 94 before the top swap. I ran injectors from a series II FWD 3.8 and they were enough to give me more fuel with out ****ing up to bad at idle. If you want to stay with the little 16s you can just go ahead and enjoy hotter running temps, less than stock power and a constant miss fire you will NEVER figure out.

[jrocstar]

Re: Fuel options...

What Are You Using For Bsfc This Is The Formula To Figure Out Injector Sizing

[jrocstar]

Re: Fuel options...

if he was operating at 85% duty cycle and had a bsfc of a extremely well built engine wich let's not lie to ourselves it is a gm v6 good god why are we even doing these calculations for this engine. say he has a bsfc of .50 which is possible but not likely then yes (16*.90 for duty cycle)/bsfc or .5)*6 number of injectors then yes that means those injectors can achieve 172.8 hp. but this is a engine with just a cam change not anything special in the least bit. but injector sizing calculations also show that to find 220 hp you would take horsepower and divide it by 6.8 to find ideal injector duty which suggests 32.35 lb/hr i am going to stick with corky bell and say that this guy is running a worse bsfc than figured. here is a idea just get the adjustable fpr lets say you are running 48 psi currently just for bottom line worst case scenario then you take new flow rate=the square root of new pressure/square root of old pressure*old flow rate
so a 3.4 with 17lb injectors increased to 60psi so we have 7.746/6.928*17 will yield you 19 lb hr approximately. all calculations are assuming zero loss of flow during wot which does not happen and does not adjust for climate or altitude which will affect air mass and the weight of fuel. you will be increasing pressure too much to really get alot out of those injectors probably the best way to do this is scale the maf and install 19lb/hr injectors this will keep idle fine and wot perfect. this takes alot of work but to have a proper tune it must be done. and it has been done with much success. or you can put 19 lb/hr injectors in and run it. the reason it goes rich down low is not only the increase in fuel pressure but the fact that a cam produces less vacuum at idle and messes up your ve table anyways so pretty much you are boned any way you look at it unless you go with a fmu that moves up pressure to accomidate intake pressure or a scaled maf with larger injectors
god i hate pre obd2

[tkoforpresident]

Re: Fuel options...

sweet, i'm boned either way.

:tdown:

[nascar24jd]

Re: Fuel options...

Hey Max -

If you recall I have a 1993 3.4L as well. Great engine.

However, with that being said your cam swap sounds like a lot of time and money for very little power gain.

If I were you I would think about it a little more.

[tkoforpresident]

Re: Fuel options...

Hey Max -

If you recall I have a 1993 3.4L as well. Great engine.

However, with that being said your cam swap sounds like a lot of time and money for very little power gain.

If I were you I would think about it a little more.

plz pm me about this kind of stuff.

imo modding an engine isn't ALL about how much power you gain. I took apart my top end for the first time this winter and had a blast just working on my car and learning and all i did it for was to put on some roller rockers. It's a hobby, but you know that.

[nascar24jd]

Re: Fuel options...

I could not agree more on the hobby part. It is fun to work on your car. I would just pick and choose your mods carefully.

Anyway, I will follow the posts and if I see an area where I can offer advice while your are doing the work I will chime in.

[tkoforpresident]

Re: Fuel options...

I could not agree more on the hobby part. It is fun to work on your car. I would just pick and choose your mods carefully.

Anyway, I will follow the posts and if I see an area where I can offer advice while your are doing the work I will chime in.

thanks man.

us 93 3.4 guys are hard to find (seriously, i only know a handful of people here who have 93's.)

we're warriors. crusaders. rebels.


lovers.



the cam and all that might not be the most cost efficient, but it gives me another reason to tear apart my motor again, and then of course whore out my car with pics of the install. :rock:

[nascar24jd]

Re: Fuel options...

Max -

What fuel mileage are you getting with your 3.4???

I am debating on changing out the Oxygen sensors in mine to see if my fuel mileage improves any. Right now I am getting about 15mpg local driving with the A/C on all the time.

[tkoforpresident]

Re: Fuel options...

Max -

What fuel mileage are you getting with your 3.4???

I am debating on changing out the Oxygen sensors in mine to see if my fuel mileage improves any. Right now I am getting about 15mpg local driving with the A/C on all the time.

i'm only gettin about 17-18

but sometimes i drive with a heavy foot.

didn't u start a thread about this a while ago?

just pay the 25 dollars apiece for both o2's, take 15 minutes to change them and call it a day.

even if you improve 1mpg after about 10 fillups you'd already have payed for them. :slap:

plus if you have a bad o2 it will create a lean mixture in your cylinder banks.

[nascar24jd]

Re: Fuel options...

i'm only gettin about 17-18

but sometimes i drive with a heavy foot.

didn't u start a thread about this a while ago?

just pay the 25 dollars apiece for both o2's, take 15 minutes to change them and call it a day.

even if you improve 1mpg after about 10 fillups you'd already have payed for them. :slap:

plus if you have a bad o2 it will create a lean mixture in your cylinder banks.

Yeah, I am running rich for sure. It's been really crazy at work so I just have not had the time to mess around with it, but I think I will change them and see what happens.

The car runs fantastic, just rich. That's why I was asking. If you are getting 17-18 without A/C then my 15-16 with A/C is probably all I am going to get.

[tkoforpresident]

Re: Fuel options...

i'd switch em out. they're not hard to get at.

[usp55]

Re: Fuel options...

i just did 330 to the tank and i rocking 275's and 315's out back on some heavy tt2's. I think its a 14gal tank so thats 23.5mpg and i like to hit it at the lights :) I drive 50/50 highway/city. I would change your o2's. i did my one about a month ago and it was really easy.

oh i dont run the a/c - ttops all the way