I need an opinion if you guys can spare one.

I'm running 730 ecm now on a blown 355.. We're talking around 720cfm of airflow under full boost.

I'm running a 280/288 (224/230 @.050) /.502/510lift camshaft,
ported plenum/slprunners/edlbrockintake/ 200cc cast iron SP-II heads with 72cc chambers and trw forged flat tops for a wopping 8.96:1 compression ratio.

Ford SV0 24lbs injectors with a 38psi idle, 43psi WOT, and 65ish psi under full bost thanks to the Vortech FMU. Timing is 25d under full boost. (with no detonation).

Stock ac-delco fuel pump in the tank, and a 155lph inline pump in the engine bay. Both run at the same time..

Car runs 110mph every time, with a best of 12.60 and a worst of 14.20 (all at 110mph). Havn't run it with the slicks.

And NOW for the questions!

1) Do I need a larger fuel pump up front, if so should I replace the 155 with say a 255, and leave the factory running, disconnect the factory, or wha?

2) Do I need larger injectors than sv0 24s?? (I hear they're really like 26#).

3) Do you think I have enough fuel (with my current two pumps) to run a line off my fuel rail to a wet NOS fogger nozze, with a 50hp jet to spray a little n20, or am I maxing out my fuel system?
(I guess I'd have to know if any is making it down the return line.. I guess so??)

-- Joe

 

I run a 304 pump, and 55 PPH injectors on my lil v6.

I consider FMUs as a bandaid.
I'd suggest you use an actual 2 bar calibration like the syclone.

Being marginal on fuel can be expensive. Bigger injectors, and fuel pump are just cheap insurance, IMO.

Google for RC Engineering and they have a nice little calculator for figuring out injector sizing.

 

Hey grumpy,

Interesting..

That calc says my car should see 36.07# injectors @ 65psi rail pressure.. (based on my desired HP), which is about 182lph right?

I'm not entirely sure I think that calc is acurate. If so, a 410hp supercharged engine would require 34lbs injectors at 45psi? Thats a LOT of fuel. Tim has to be around 500hp at the flywheel and he's running what, 30# injectors??


-- Joe

 

I'll say this again ...

Don't do anything or make any changes unless you have proof. Are your O2 mV very low or unstable at WOT? If not, then you don't need injectors or a pump. So far, I haven't seen anything that indicates that you NEED injectors or a new fuel pump.

I agree with Grumpy with regard to cheap insurance .... but don't expect these items to give you increased performance. Fact of the matter is that if your current system is supplying enough fuel at WOT then making those changes will do nothing except give you peace of mind and a lighter wallet. Personally, I like the peace of mind.

So, what I would ask is for you to do a WOT run and then post the data. A WB O2 would also be very useful here.

Tim

 

Tim,

I edited my post before you got a chance to reply cuz I've been sitting here calculating this for about a half hour.

I'm not entirely sure that I think I'm "out of fuel" but if I add my WET NOS kit, than I might very well be.

Heres a log on a 70f day before I took the car apart..

*NO* wideband o2.. <H3>
<PRE>

RPM Spark Knock o2 Inj PW MAP
4975 44.3 8 455 3.59 53.79
4975 44.3 8 283 3.62 54.51
5100 44.3 8 513 3.65 54.51
5050 44.3 8 535 3.59 53.79
5000 44.3 8 588 3.59 53.79
4975 44.3 8 610 3.56 54.15
4975 44.3 8 606 3.52 53.79
5100 44.6 8 371 3.62 54.15
5100 30.2 8 80 7.92 96.69
5200 31.3 8 22 8.19 101.34
5125 31.3 8 44 8.13 101.34
5125 31.3 8 31 8.19 101.34
5150 31.3 8 27 8.13 101.34
5125 31.3 8 31 8.13 101.34
5150 31.3 8 31 8.19 101.34
5225 31.3 9 66 8.13 101.34
5175 31.3 9 49 8.13 101.34
5250 31.3 10 44 8.13 101.34
5275 31.3 10 57 8.13 101.34
5250 31.3 10 62 8.13 101.34
5300 31.3 10 66 8.13 101.34
5275 31.3 10 66 8.13 101.34
5300 31.3 11 71 8.13 101.34
5425 31.3 11 75 8.13 101.34
5375 31.3 11 75 8.13 101.34
5450 29.9 11 84 8.13 101.34
5425 29.9 11 57 8.06 101.34
5425 29.9 12 57 8.06 101.34
5450 29.9 12 62 8.06 101.34
5450 29.9 13 66 8.06 101.34
5425 29.9 14 62 8.06 101.34
5500 29.9 14 57 8.06 101.34
5550 29.9 14 71 8.06 101.34
5425 29.9 14 66 8.06 101.34
5525 29.9 14 66 8.06 101.34
5400 28.5 14 71 8.06 101.34
5500 28.5 14 57 8.06 101.34
5500 28.5 14 66 8.06 101.34
5625 28.5 14 71 8.06 101.34
5525 28.5 14 66 8.06 101.34
5550 28.5 14 71 8.06 101.34

</PRE>
</H3>

I take out 1d per psi with the MSD BTM, so subtract 8 from the timing..

I was running 1.5" flowtech headers and 2.5" exhaust all the way back.. Thats all replaced with 1 5/8 headers, 3" catback. I also am replacing the stamped roller tip rockers with some full roller rockers, and replacing the broken harmonic balancer with a fluiddamper.

I'd like to install my NOS kit too, but I'm worried about fuel and don't know enough about fuel requirements to judge..


-- Joe

 

You need fuel ... bigtime.

1) First verify that the fuel pressure doesn't drop at WOT. If it does then you need a new pump capable of flowing what the car demands.
2) Have you modified your bin in an attempt to supply more fuel? If so, does it produce an O2mV increase?
3) Raise the pressure at the rail. Try 48-50psi.

As I mentioned before - I like the idea of going with bigger injectors and a nice big pump. But, I just got this feeling that you were looking for an automatic performance increase and this just won't happen unless your car actually NEEDS that fuel. In your case - it does.



Tim

 

Grumpy,

Your right the FMU is a bandaid, but without it i'd have to run very large injectors as my rail pressure would be aboue 20psi lower. Also, I don't want to run the $58 stuff right now because of the lack of support from moates datalogger. I've tried some other logging programs and have not been very happy with the way they work, honestly.

-- Joe

 

Hah. wow. You made me laugh.

I might have 1 new log after some inj pw @ PE changes.. The FMU nails my rail pressure at about 60-65psi. And this is with the svo-24# injectors.

Lemme see if I can find a slightly newer log and see if it has the same output. I think I got my injector pw to around 10s..

-- Joe

 

This is so conflicting..
Next day, modded VE and changed inj pw a little bit under PE.
Fuel is sunoco 94 octane, with a bottle of nos octane booster, race formula. (prolly worth a point?) About 70f outside.

I added the AFR to give you an idea of what I did in PE or what the ECM thinks i'm doing.. The AFR from the other table, was 11.93..

<h3>
<PRE>

RPM Spark Knock O2 Pw AFR Map
4050 43.9 29 539 2.73 14.71 38.42
4000 45.7 29 309 3.42 14.71 45.22
4050 24.3 29 667 7.26 14.71 86.32
4200 34.5 30 44 10.27 10.9 101.34
4100 34.1 30 243 10.54 10.9 101.34
4300 34.5 30 778 10.09 10.9 101.34
4250 34.5 30 800 10.27 10.9 101.34
4400 34.5 30 813 9.99 10.9 101.34
4450 34.1 31 818 9.92 10.9 101.34
4425 34.1 31 822 9.99 10.9 101.34
4525 34.1 31 822 9.84 10.9 101.34
4600 33.4 31 822 9.64 10.9 101.34
4675 33.8 31 818 9.55 10.9 101.34
4650 32.7 31 813 9.55 10.9 101.34
4650 32.3 31 813 9.41 10.9 101.34
4725 30.9 31 809 9.37 10.9 101.34
4775 30.9 31 804 9.37 10.9 101.34
4825 30.9 31 800 9.37 10.9 101.34
4875 30.9 31 787 9.37 10.9 101.34
4975 30.9 31 782 9.37 10.9 101.34
5050 30.9 31 778 9.37 10.9 101.34
5000 30.9 31 774 9.37 10.9 101.34
5000 30.9 31 765 9.37 10.9 101.34
5100 30.9 31 756 9.37 10.9 101.34
5200 30.9 31 747 9.37 10.9 101.34
5200 29.5 31 747 9.37 10.9 101.34
5175 29.5 31 751 9.37 10.9 101.34
5275 29.5 31 738 9.37 10.9 101.34
5375 29.5 31 734 9.37 10.9 101.34
5275 29.5 31 729 9.37 10.9 101.34
5450 29.5 31 720 9.37 10.9 101.34
5350 29.5 31 729 9.37 10.9 101.34
5500 29.5 31 725 9.37 10.9 101.34
5425 29.5 31 738 9.37 10.9 101.34
5500 29.5 31 720 9.37 10.9 101.34
5500 29.5 31 725 9.37 10.9 101.34
5625 29.5 31 725 9.37 10.9 101.34
5650 29.5 31 720 9.37 10.9 101.34
5625 29.5 31 738 9.37 10.9 101.34
5650 29.5 31 725 9.37 10.9 101.34
5750 29.5 31 720 9.37 10.9 101.34
5825 29.5 31 738 9.37 10.9 101.34
5775 29.5 31 734 9.37 10.9 101.34
5775 22.9 31 743 6.74 14.71 101.34
5550 25.7 31 809 1.74 14.71 37.71
5100 27.1 31 791 0.76 14.71 21.27


</pre>
</h3>


So it looks like the increased PW helped a little but, at 5700 rpm a 9.37pw is what, like 90%dc?

The o2 sensor is BRAND new, like this summer bosch direct fit. But as any other non heated o2, its almost a crapshoot compared to a wideband.


-- Joe

 

I figure with a sv0 24 pegged at around 93% dc, i'm pushing around 165 or so lph. So the natural choice would be a 255lph pump.

A 255lph should be able to support around 720hp shouldn't it?


As far as injectors go, my "goal" is around 500-510 crank HP, so I'm thinking if I keep the FMU 36pph injectors at 80% DC should handle that no prob. If I wanted to run w/out the FMU ($58 code) and had a rail pressure of say 50psi then it would be like 42pph injectors, right?

My math ok?

-- Joe

 

What happens if you crank up the PE table some more? Can you get in the neighborhood of 900mV (only suggesting this because you don't have access to a WB)?

For 500 crank horsepower you're looking at 30lb SVOs at a minimum (if you are striving for 80% DC or less). FWIW - I estimate to be in the 475 crank horsepower range and I'm running 30lb SVOs at 82% Duty Cycles. 36lb injectors would be a fine choice in my book ... while still giving you room to grow.

AFAIK - the Walbro 255ltr/hr pump is only rated to about 550hp. You'll definitely want to get the high pressure version of the 255 pump.

Oh yea - you are currently at about 91% DCs.

Tim

 

You can make well over 400 HP with 24 lb. injectors right?

I thought ski-dn-it was making like 450 something with 24 lb.er's ?

Oh, and what happened to that guy?

 

OK so we gonna put a walbro 255lph pump inline to replace the 155lph. These are like 99.00 on ebay new (http://cgi.ebay.com/ebaymotors/ws/eB...tem=2446150772)

Then we're gonna put some Accel 36pph injectors.

Should I even keep the power connected to the stock one in the tank, or disconnect the power?? I don't really want to take that pump out though.

-- Joe

 

im pretty sure the vortec EFI v8 fuel pump will cover your fuel needs plus its rated at a higher then ave fuel pressure cuase the vortech v8's run like 70 psi rail.

 

Calculated flow based on pump size is kind of bogus, from what I've seen. In some cars actual useable fuel is 1/2 or less then pump rating. Folks might cruise the GN area, as there seems to always be some controversy about what is enough pump and or injectors.

I had a typo when I wrote 304, it should read I have a 340 for my car, and today I ordered a double pumper. That will be two 340 l/Hr pumps. The second one coming on at 5 PSI.

HP claims have gotten so out of hand nowadays that the topic is laughable, IMO. I've already posted about some of the errors that are commonly made nowadays, so I'm not going to repeat myself on that front. Suffuce to day there is a difference in sustainable HP and flash readings. You can't do the math based on one type of reading using HP from flash readings, with any accuracy.

I don't understand the fashination with using as small of injector as possible. Again, did a sticky on it, and in short if you want to use GM methology, then you base your injector sizing on the same principles as GM does. If you want double the HP use double the injector, it's just that simple. If you want to run open loop then just use the BSFC and predict what size to use based on that. And with the NASCAR teams struggling to bet .45, I'm amazed that so many guys think they can do better then .45, with mufflers.

Just trying to bring things into some sort of rational thought.

 

Build an ecm bench, and then transfer the data learned.
And, update to another data logging system, as needed.
Maybe work with Moates on doing a 58 version of data logging, it just a matter of rearranging the data stream for the different mask.

 

Gets back to my comments about flash HP readings.
But not using pump gas. Mixing your own fuel can put you into a different category. Remember also BSFC is based on lbs of fuel, so when you increase the density of the fuel your also increasing the WEIGHT of the fuel. Change the density 10% and bingo you instantly have 10% better BSFC numbers.
He, was banned.

 

IF I went with the $58 code, with a max pressure of 50psi i'd need what, a 40pph injector?

I dunno. I have quirks in my stomach about $58. It sounded great at first, but then. I dunno.. I have a bin and I have a TC def I bought I just.. feel weird about it.

The _good_ think about running $58 code would be i'd have a actual static rail pressure.

If I set my PE enable to be a slightly higher tps, and assume whenever we're in PE we're in boost, couldn't I than just set my PE fuel adder there to get my PW where I need it and remove the BTM? Or would that be "unsafe" ??


-- Joe

 

Did you notice how you O2 reacted?.
11.9 to 10.9 and you went from 15 mv to 700mv. If this isn't testiment to how poor of sensor they are, I don't know what is.
And or, it shows what the injectors MAY be doing. ie in that 10% DC difference they're going from an indicated lean, in your book to an indicated, OK, again in your book.
A NB is absolutely worthless, to me, just in what you've shown.

So where are we?.
Do you think your doing NASCAR caliber work with BSFC numbers, or that there maybe an error in the accepted understanding in what's going on?. At 8x24 we have 172 PPH, times .5 that'd be 344 on the best of days. For a blower motor given a good sized cam .5 is what I'd guestimate at. But others will want to be ever the optimists, and guestimate higher. But the optimistic numbers game can play games.

For the 100 bucks it'd cost to get a couple sets of take out Gn injectors, IMO, it just not worth the exposure to fight erratic injectors. Your way way way safer to run at 80% DC then anything near 90. Now that's fact, fire up an ecm bench and listen to a injector go erratic, and you all of a sudden get really clear on what's going on.

Just trying get folks to objectively look at what they're doing.

 

Your absolutely right, I need some wideband work.

I'm looking at guestimating what the setup "should" be at.. a 8.96:1 engine with the parts I have, and a blower running at 720cfm should produce around 475-500hp right? Ok. So where do we need to be for injectors..

Tims running 30# svos which are really like what a 32-34? And at what 50psi? So I figure I should be able to get away with about the same with my 65ish psi FMU, or maybe some 40s with a 50psi rail pressure..

I'm thinking at 50psi rail pressure, you could get away with 500hp at 85% dc.

no?


-- Joe

 

Since people seem to be talking about various things here ...

I remember when I was on the GMECM list oh so long ago. I posted about going with 30lb SVOs for my IROC and received tons of comments from everyone ... including guys who now participate on this board ... that those injectors were way too big. I explained my reasoning which was extremely similar to what Bruce indicated above. Nobody wanted to listen. I went with the 30s anyhow and reported my great experience with them. Next thing I know, everyone seems to be recommending to over-injector a car. Weird how people's opinions change. I was telling people to overinject cars years ago because you really don't have anything to lose. Years later everyone saw the light. Hmmmmmmmm.

The normal band O2 sensor isn't completely useless. Those who say that it is completely useless haven't taken the time to ask themselves ... "Ok, what can I get out of this besides nothing". My O2 is a quick sanity check around 880mV for being close to on-target for WOT. Admittedly, I say this because I have done comparisons of my Wide Band vs. my normal band. The normal band is terrible for AE analysis, it responds slowly, but it is a good sanity check for running dangerously lean vs. running rich. IMHO, if you can easily get your O2 mV a good deal over 900mV then you are in a safe AFR range. That does not mean that you are running an optimal AFR ... nor does it mean that you know where you are AFR-wise. I'm just saying that you are running a rich, safe AFR.

I've seen several cars running unboosted code (i.e. stock AUJP, LT1 code, etc) and no FMU that had been tuned off the PE tables and they did run AOK. There were definitely some part throttle problems. But, WOT can be tuned. Now, with that said, my recommendation is that if you want to do it right then you have to convert over to the SyTy ECM and run $58.

If it were me I would run $58 in a 749. I would then rip out the in-tank pump and replace it with pipe and a filter. If you try to use an inline pump to pull through a dead or crappy intank pump then you will eventually have problems. Just rip it out and replace it with a pipe and filter. I would then install a very high flow Aeromotive or Paxton in-line pump that can support up to 800hp. The Walbro 255 just won't cut it when you eventually build your motor up. It will be fine for the short term but do it right the first time and you won't have to deal with it again. Finally, remove the FMU and install some big injectors. A set of 36lb SVOs will actually flow close to 40lb/hr at GM standards and will be absolutely fine for what you are doing now along with providing room to grow. The next step would be to go up to the 42pph injectors. But, those SVOs will flow closer to 46-47pph. At that point your idle will become a concern due to running very low pulse widths at idle. I have experience with the 36's and got them to work. I don't have experience with the 42s ... but I bet it's gonna get close.

Tim

 

I'm only running 43psi at the rail and running 117mph in the quarter mile. You do the math on horsepower I could easily crank the pressure up to 50psi, redo my injector constant, and run lower Duty Cycles (currently 82%). However, there's no need right now. IMHO, these injectors can easily support significantly more horsepower than what I am currently pushing.

In any case ... given your motors potential, I still think the 36's would be a better choice.

Tim

 

What i'm trying to do right now is "finish" this project, so I can move on to other things. (like buying a house) I think I can get more out of the motor and blower, and thats my goal really.

I'm running a Vortech A-trim. Its max output is 720cfm, and suposedly max it supports is about 480hp.

I'd like to max out the potential for the blower I've got. The motor is not getting redone again. Its just getting done as best as it can for what it is ..

If I wanted to do it over, the heads and intake would go on ebay to be replaced with some afr 190s and a victor efi intake, and the A-trim for a S-trim or better. But I'm not willing to go that far. I'd like to see 11s with the current setup. thats all. I just need to shave off 6 tenths..


SO!

I'll swap the pump, and the injectors for perhaps some 36's. If this blower can't support more than 480 or so 36s will be the limit at 50psi anyway..

As far as sy-ty goes. I dunno. I have everything. the 749, the code, I even made a bin and imported most of my $8d stuff so it will be close as hell. I just. feel weird about it. Maybe I need to talk to saturn and bort a little on how there stuff's going..

Thanks guys! I think I've learned a little again.


-- Joe

 

One thing though.. If one was to remove the intank pump completly, and upgrade the other pump. Does it make more sense to run a inline in the engine bay, or run a intank?

-- Joe