Fermin91rs305

Hey guy I just bought a Holley stealth ram with all the upgrades and stuff putting it on my soon to be a 383 stroker. I'm putting a new upgraded fuel pump I believe it's the walbaro 255 and I'm wondering what size injectors I would need or the best to match..

alek72us

we need to know what heads are on the 383 and what the 383 is bored out to.
probably around 30-40lbs injectors.

Fermin91rs305

Sorry it's my 350 l98 that I'm going to be stroking out to a 383 and my heads will be stock aluminum heads from the l98 just ported out with Lloyd elliots LE2 package with a 230/236 112 cam. I saw some accel 32lb injectors or some Trick Flow 30lb injectors.. I don't
Know which ones to go with..

old z mzn

iTrader: (1)

get a matched set of injectors. makes tuning a lot easier.

birds8869

Matched set, what does that mean? Also the question of which set of injectors to get was not answered. I have about the same setup and would like to know what is the best BRAND of injectors to get.

scamaro355

30lb injectors will be fine for what you are planning... thats what im running with no problems at all

InjectorsPlus

iTrader: (1)

Not enough information. Give me the exact specs we'll DD it and come up with something.

birds8869

Thanks for the suggestion, called injectors plus and ordered 32lb bosch gen 3's, very helpful tech.

old z mzn

iTrader: (1)

I had accel 24# went to matched 32# bosch gen 3"s.... tuning was very easy.

anesthes

iTrader: (12)

On an intake that flows different on every runner? (Horizontal draw)



-- Joe

InjectorsPlus

iTrader: (1)

Thanks.

InjectorsPlus

iTrader: (1)

There's always a work around, duct tape will do I think....

anesthes

iTrader: (12)

Duct tape fixes everything.

I need your paypal address. I owe you $75

-- Joe

InjectorsPlus

iTrader: (1)

Payment@injectorsplus.com

And if anyone else wants to throw in a few bucks, feel free...

Orr89RocZ

iTrader: (20)

Yep good choice, 32lbs will be plenty for that. Should be a stout 383..watch your compression with those L98 LE2 heads....

Fermin91rs305

With my setup up whAt do you think
Will b the best compression for the l98?? Help I'm new and want the best thanks

InjectorsPlus

iTrader: (1)

Best compression? I wouldn't go over 10.5 if you're using pump gas. If you're thinking forced air, 8.X-9.5 will work. There are no answers in a vacuum

As to the injectors, still need more info....heads, cam, compression...start there.

the answer is somewhere between 24 and 36 pounds....

So help us narrow it down.

Orr89RocZ

iTrader: (20)

With that cam, 10.5 would be great on pump gas which will require a deep dish piston since L98 heads are 58cc as cast and LE will shave them abit to make sure the deck is straight so they may be as low as 54-56cc. Thats gonna create very high compression with a flat top piston so you will need a big dish.

InjectorsPlus

iTrader: (1)

AHHH crap, I missed that post....DUH! Thanks Orr. I'll respond.

InjectorsPlus

iTrader: (1)

Neither. Honestly. Neither. Neither Accel or TFS make their own injectors. They are Lucas, Bosch, or Delphi I'm not 100% sure which as they all change from time to time. Do not pay more for a name.

Now, a 383 with that size cam and those heads, I'd look at 36lbs. I like injectors a little bigger, it's safer than going borderline small. I'd expect about 450 CHP with a Stealth Ram setup, give or take. So yeah 36 Bosch.

As to the compression like Orr says, 10.5 is a nice range. I think this is a great combination and you're going to enjoy it. Should fall off over 6000 RPMs.

Give me a call on them. 201-258-5600 We can work it out.

anesthes

iTrader: (12)

I'm at 10.8:1 on pump gas, but a nasty big cam.

My truck is 18:1, and 24lbs of boost

-- Joe

anesthes

iTrader: (12)

Some guys have good luck with big injectors, other guys have problems. I guess it all depends on the injector. I'd run a 36# injector to 550hp on a naturally aspirated motor, because I'd rather run a 50psi rail pressure with a nice spray pattern, and a reasonable idle pw than dance on the 'erratic' idle side of things just to keep the DC down. I've never had a problem with bosch II, or bosch III's going static like the older rochester injectors. But I have had issues at idle with motors that had tame cams and low compression but ran MASSIVE amounts of boost and needed the fuel at WOT.

Though, a 36# injector would probably work fine for a 450hp motor too. I'm happy with idle pulse widths in the 2ms range. You can always make an injector look a little bigger by raising the fuel pressure, but when you try and go the other way you risk issues. Injectors to me are like cams, start small because too big will bite you.

-- Joe

InjectorsPlus

iTrader: (1)

I'm running 42s on a similarly powered engine, slightly higher. I'll admit they're a little large, but they work. I do agree with raising the fuel pressure as a fine tune. Different ways to skin a cat. But understand, when people say to me "what injector should I use" I err on the larger side. I don't want to make a suggestion that's going to melt a piston...as I have seen happen more than I care to.

anesthes

iTrader: (12)

I understand your position on that. But it's also up to the guy tuning the motor. I have no problem running DC's into the 90s.

Just for numbers sake, at a BSFC of .55, which, for a N/A motor means you totally missed the combo but lets err for caution, at 50psi rail pressure which is quite reasonable, 36# injectors will support 500hp at 90% duty cycle.

Now one thing to take into consideration is is RPM right - a 230/236 cam on a 383 is going to be done by 5800, so in theory you have about a 10ms firing window before going static on a typical batch fire ECM.

-- Joe

InjectorsPlus

iTrader: (1)

I always ask people "what did your tuner tell you" and will go with that unless they are so far off it's dangerous. I will give my 2 cents if it's right or not with something like "I'd like to see you bigger". For example, someone called me yesterday about 72lb injectors that his tuner said he needed. I reccomended he go with 80s for 2 reasons...1. some overhead 2. 80s are "off the shelf" I have to MAKE 72s. If there's an off the shelf answer I prefer that to custom configs.

Yeah, I like to keep the DC in the 80s. Everyone has their preference and none is right or wrong. I like having more than 10% overhead, for no good reason other than it makes me fee better.

YEP!


I think he can get better than 5800 RPM thinking 6000...have to put it together to see. He does have the LE heads....

anesthes

iTrader: (12)

Two things to consider. What the motor will spin to, vs where it will stop making more power.

The motor will probably valve float around 6500rpm or higher, and most guys do shift past peak HP. But past peak HP the fuel requirements diminish, so while your DC quickly approaches a higher percentage, your AFR actually richens up a little bit.

Different stuff works for different combos.

I've changed my ways quite a bit over the past 10 years. I used to promote big injectors and precise closed loop tuning but over time I've found that what works on a RACE CAR is not even close to what works on a daily driver. Now, I run open loop only, smaller injectors with high rail pressure, crap tons of initial spark advance (24-26* at idle, and add 10* by 2800 RPM for wot), no PE spark. Many sessions of tuning cranky minirams and friends stealthrams with big fat cams have made me throw many 02 sensors in the garbage and instead tune for 'best performance, most idle vac', etc.

-- Joe

InjectorsPlus

iTrader: (1)

When I talk about "spinning to" I mean making power to....

[/quote]The motor will probably valve float around 6500rpm or higher, and most guys do shift past peak HP. But past peak HP the fuel requirements diminish, so while your DC quickly approaches a higher percentage, your AFR actually richens up a little bit.

Different stuff works for different combos.

I've changed my ways quite a bit over the past 10 years. I used to promote big injectors and precise closed loop tuning but over time I've found that what works on a RACE CAR is not even close to what works on a daily driver. Now, I run open loop only, smaller injectors with high rail pressure, crap tons of initial spark advance (24-26* at idle, and add 10* by 2800 RPM for wot), no PE spark. Many sessions of tuning cranky minirams and friends stealthrams with big fat cams have made me throw many 02 sensors in the garbage and instead tune for 'best performance, most idle vac', etc.

-- Joe[/QUOTE]

Any miniram advice? I'm in MR hell.

My ECU (motorvation) allows setting parameters for closed loop. You can set RPM, TEMP, just about any parameter. If it's not THIS stay open loop. Do idle is at open loop, once it hits 1200 RPM I throw it into closed.

anesthes

iTrader: (12)

Well.. Here is the thing. I've run minirams on both autos and stick cars.
On an auto (700R4) with 3.54 gears, a cc-306 cam, miniram, and a small block I it was ok with a loose (3k stall) converter. Manual transmissions amplify problems with the tune, where loose automatics kind of dull the issues.

Now as far as idle, I could never quite get the MR to idle properly. I had patched bins that would disable closed loop at idle, and resume closed loop at
> 1100rpm, but even then the transition was hard to fix.

The miniram has the same problem at lot of those intakes do. You have 8 cylinders running differently, and one narrowband 02 sensor trying to figure out if it's rich lean or in between.

My advice is to not use closed loop at all. Lean out idle, ramp in tons of advance to get good vac. Work out your AE transitions, and build a nice cruise map with high 40s SA, and a nice lean burn. Then tune PE fuel for best power.

Another thing to be careful about, is make sure your staying in your powerband. You load the thing up too much under your powerband and you'll have all sorts of issues. I know my C4 had 2.59 gears stock which were laughable with anything that even comes close to a 'performance' camshaft. A 3.54 gear ratio is about on par with a 700R4 and a mild performance cam (230*)

-- Joe

Orr89RocZ

iTrader: (20)

Thats the way I've been doing my motors. Give it lots of advance and fairly lean idle if possible.

I also run abit larger injector now. I had 42's on my 400whp 383 which probably could have done 36's. No idea what the PW were so no idea what the DC's were. My 401TT motor I have 80's running 48psi. I think i'm near 84% DC if calculated right but its abit richer than i need it so still have abit of room to play with. It actually idles fairly well for being a larger injector (newer siemens).

now your idle defination of "nice" may vary, but I am happy with it. Stable in drive and doesnt stall but its abit higher rpm than I want. Still need to tweak.

My 383 was a MAF car so didnt have to pick to hard at VE tables like the 401TT motor. MAF compensates well. Some other motors I've helped tune were all MAF's too. Various 350-383 setups. Idle well with a big cam too. Some closed loop, some open. Both did ok on MAF but my setup was all open loop.

Depending on the lobe shape/lift that 230/236 cam may go abit beyond 6000 rpm peak. My 230/245 went to 6250 peak and held to 6500+