420A FUEL to BOOST

[95VENG]

After lots of searching im curious about how much boost i can run using 91 octane. Also just wanting to see the difference and comparison to 8.8:1 pistons with h beam rods, vs stock compression. I just want to get as much power as i can using pump gas. Just asking for experiances or any kind of info

 

[greydelta38]

After lots of searching im curious about how much boost i can run using 91 octane. Also just wanting to see the difference and comparison to 8.8:1 pistons with h beam rods, vs stock compression. I just want to get as much power as i can using pump gas. Just asking for experiances or any kind of info

I don't think the question is 'how much boost can the gas handle' so much as 'how much boost can the 420a handle'. To answer your question, I've seen guys run anywhere from the stock 12 pounds to 35 pounds, but using it in a 4g63.

 

[TSicktalon]

As much as you can get away with without knocking.

 

[Chad1993]

Advance your fuel all the way on link, then retard your timing all the way. That should do it . JoKInG!!!

 

[greydelta38]

Advance your fuel all the way on link, then retard your timing all the way. That should do it . JoKInG!!!

Oh, no wonder John Shepherd is so fast! That's probably what he did!

 

[95VENG]

its a 420a and i will have forged internals. with 420a we dont have any tuning software. only fmu and mega squirt. My goal is make as much power as i can as a dd. It pulls pretty decent at 8lbs but now that im used to it, kinds wanna turn it up a few lbs. Boosting with my 01silverado was much easier since i could tune it.

 

[jayson427]

It's all about the tune really. Guys run 10.5 compression on 91 pushing 15-25psi on a built motor with a perfect tune. Mark bullet has made alot of power using 91 and other people have too. But the higher the compression the small Window of error you have with tuning. And keeping egt's down is something that you deal with also that's why most people run e85 when they make big power.

 

[jayson427]

its a 420a and i will have forged internals. with 420a we dont have any tuning software. only fmu and mega squirt. My goal is make as much power as i can as a dd. It pulls pretty decent at 8lbs but now that im used to it, kinds wanna turn it up a few lbs. Boosting with my 01silverado was much easier since i could tune it.

Megasquirt can be a full stand alone ems which is capable of tuning anything you have with the right knowledge and experience. You can even use a aem ems if you want to go crazy with it.

My ultimate goal is 15-18psi on 10.5 compression with pump gas using megasquirt.

 

[95VENG]

good point. im trying to make some good numbers my keeping the car as efficient as possible. If there was tuning software available for these motors i would probably just been able to tune it. just thinking of possibly keeping the stock compression 9.6:1 and maybe 330cc injectors with 12:1 fmu which will keep it getting plenty of fuel but just curious about the amt of boost i can get away with. I tried to get away with 10lbs which i did for a lil bit till number 2piston compression ring went kaput. Which sucked because that lil car pulled pretty hard at 10. my goal is 12lbs safely

 

[TSicktalon]

MS and AEM can be run on your car. They are both tunable software, so stop saying that there isnt any.

You can up the boost until:

a) You see knock
b) You outrun your fuel system and run lean
c) You break stuff

On a 420a, I have no idea in what order those items will occur, but 330cc injectors are tiny.

 

[jayson427]

What do you mean by tuning software? Because there's a few options for our cars.

If you had megasquirt you wouldn't need a fmu. Just an afpr with a boost controller.

If you didn't go with megasquirt I would get a sfmu, safc2, Wideband and bigger injectors/fuel pump. You could get away with 15psi easily on a built bottom end running stock compression.

 

[95VENG]

well factory injectors are like 220cc so those are an upgrade. i know aem and megsquirt are avaiable and tuneable but didnt want ot have to go that route. but looks like i may have to eventually. hate messing with wiring. if im getting mega squrit then just going with the 440cc i have already. bottom end will be built. ill probably go with SAFC2 and some bigger injectors for now.

 

[glowryder]

Dont even bother with the SAFC.

Youll need to pull timming once you hit a certain threshold. Youll need to pay attention to knock, as that will kill the motor if you let it go. running lower CR will help shift this window, but not erase it.

To get "most power with 91/93" youll need MS. hands down.

you can run 12 psi on stock bottom, but youll be running so rich to keep knock down, youll rob the power gain. think of it as a bell curve. Its been proven time and time again, ~8psi on a s16g is about the limit on a stock block.

 

[boost97gst]

The temp of the air coming in to the engine plays a huge role in how far you can take pump gas. Thats why on pump you want the most efficient IC you can afford and its optimal to run a larger turbo. The bigger turbo will flow HYPOTHETICALLY** lets say 30lbs/min at 15psi where a smaller turbo will flow that 30lbs at 30+psi. Just random numbers to get my point across.
The smaller turbo is working harder and pumping out hotter air and needs more boost to make the same power. Also cam timing and selection can play a role in pump gas limit.

Quick easy fix? Water/meth injection kit.

 

[glowryder]

that works, but then your loosing races because your band-aiding a problem with a larger turbo. Really, a 9.x + CR + a good flowing turbo, + MS, is the way. throw in meth or e85 (pick your poison).

Not to mention all that power will be for not with a non lsd trans and stock suspension

 

[95VENG]

i had trans built so the trans can handle it. Well looks like tax time will be going with MS is it a pain in the ass to hook up? i have done a wire tuck on my car and ecu is inside already so that might make it easier. So im sold on the MS and will be getting that bad boy, and going eagle rods and weisco pistons so that will be taken care of, now as power goes. 8.8:1 or 9.6:1. I figured if ill be going MS ill be going with factory SRT-4 injectors. They flow 577cc@58psi. so ill be able to get the fuel there.

 

[glowryder]

you can probably handle it. Its all depends on a few things.
1 how clean you want the install
2 how crazy the set up is (for example i run IAC 4 wire and Sequential) on my avenger.. so theres more wires.
3 how good you are at following instructions. Grounding is critical with MS, improper grounds can mess you up bad.. ask me how I know.. . also making sure sensors are getting clean connections, thats also key.

define built trans.. is this an a604? or nvt350? at any rate, without an LSD, its going to be pretty pointless when you push power..
I have an ERT built a604 if anyones in the market.

My suggestion would be get MS3 or MS2e at least.
If youre going MS, go with the 9.6 Cr

 

[95VENG]

its a 604 41TE. My buddy works at a dodge dealer and does lots of trans work on the side so he did a colmplete rebuild and just told me that the trans will be able to handle what i throw at it. I trust em he did my last trans for my turbo silverado and that thing took a beating. following directions im good with thats no problem. since the ms will be inside the car ill end up putting it in the glove box, best points for grounding inside the car?

 

[glowryder]

msextra.com

the silverado had what a th350? most of those trans are pretty stout because they expect you to tow things.

you'll need engine grounds too etc. its important where you ground sensors and your wideband as to not create a ground loop.

as for the a604.. from experience ,it wont hold much of anything.. no stock rebuild will make it last. the people running the a604 end up ditching it , or building it with billet components. Hope it lasts for ya, but I wouldn't hold my breath...its literally one of the worst transmissions built.

and without LSD.. youll put strain on it even more. Axle snaps in your future, if the a604 doesnt kill itself. Im guess stock stall?

 

[95VENG]

i have a spare diff for it pulled from my last trans that im currently trying to build as a posi for it. not stock stall i have a IPT 2500 stall for it. the trans also has shift kit and other goodies that i got from ipt so trans is not completely stock. where u gorund your wide band and ms?

 

[glowryder]

Building a diff.....
I'll just stop you right there. You have a few options..
1. "Diff saver tabs" your buddy at dodge should be able to get these. This will help save your diff when the pin explodes... notice how I said when....
Some people have even we led the pin in there...some used phantom grip.. all have been pretty much proven to be a waste on most levels.
2. Obx or quaife LSD.

Anything but number 2, the diff will in all certainty die... been on here and other avenger platforms for 8+ years....so I'll pat myself on the back a little and say "I know what I'm talking about". Also the fact there are 0 high HP 420a-it's running high HP. There's a reason.the ERT trans were the only thing proven to work on some of the s/c v6 avengers that people built in the late 90s early 00s.

As for the grounds... do some reading. There plenty of info out there... the site I put in there has diagrams etc...

 

[95VENG]

well looks like im limited to power based on trans. ill look at those lsd's u mentioned and make my decision from there. as for grounds i can take a look into that thx for the info man appreciate the insight.

 

[glowryder]

NP good luck! Always nice to see another boosted avenger out there.
If you do choose to run an LSD, there are some spacers youll need. they are available through a few vendors.

Id also upgrade the motor mounts, and the suspension, help get the power to the ground and control wheel hop. You could also look into equal length drive shafts, seeing as the V6 avenger (with the a604) had them, it would be an easy swap with an ELDS bracket. but that may be overkill.

 

[95VENG]

i have prothane mount right now. which i think would be ok. i use this car for a dd becasue the gas mileage in my truck suck. but for what i want, i need to do everything else that u mentioned. there are a few things i want to do for the suspension for traction. The equal length shafts i may look into down the road.