[hadagto]

Interesting article...

Port vs Direct Injection Brian Tooley Racing Reveals a Clear Winner

 

[Steel Chicken]

I never doubted DI made more power, but my concern was around reliability and maintenance. I dont follow this stuff like I used to, but many manufacturers have had significant challenges with DI failing/clogging up with very low milage.

 

[hadagto]

The only thing I've heard of is carbon build up on the valves since they aren't getting hit with fuel. It's an issue for sure. I also see the high power guys adding port injection as well as the factory direct injection. That point seems to be around 1000 rwhp or a little over on ethanol. At that point they need to add a secondary port injection fuel system. That is something I like about the C7 Zr1 because it has both port injection and direct injection from the factory. That seems to be the ideal situation although expensive.

 

[Reaperhwk]

All the big hemi engines are still port injection?

 

[Westphal]

All the big hemi engines are still port injection?

View attachment 524925

I'm pretty sure they still use port injection on the Hellcat and same with the regular Hemi engines.

 

[hadagto]

I'm pretty sure they still use port injection on the Hellcat and same with the regular Hemi engines.

I wonder if it's because they are closer to the limits of what direct injection will currently support power wise. Direct injection is proven to make more power and do it more efficiently up to its limits. Just like guys modding making 1000+ rwhp on ethanol they have to add port injection on top of direct injection to support it. Might also be why GM is running direct injection plus port injection on the C7 zr1.

 

[Reaperhwk]

All those hellcat motors are port injection. I think the most powerful crate motor makes around 1500hp(off-road though).

so port injection can get high power. I think dodge is pushing the hemi design to its limit to be true to form. If they made a direct injection hemi I don’t know of that would be considered a “hemi” anymore?

 

[hadagto]

All those hellcat motors are port injection. I think the most powerful crate motor makes around 1500hp(off-road though).

so port injection can get high power. I think dodge is pushing the hemi design to its limit to be true to form. If they made a direct injection hemi I don’t know of that would be considered a “hemi” anymore?

Yes port injection supports more power capability than direct injection currently does. That was my point...direct injection makes more power more efficiently than port injection up until you reach the limits of direct injection which seems to be around 1000 rwhp on ethanol right now. That is why GM uses both direct injection and port injection on the C7 Zr1 and possibly why dodge uses port injection on the hellcats.

For example in the article at that power level the direct injection makes more power than port injection by a significant amount. Direct injection is the way to go for efficiency and power capability up until you reach a power level that it is incapable of supporting.

 

[hadagto]

Kind of like a carburetor can support more power than direct injection as well, but it sure isn't going to make as much power or do it as efficiently as direct injection on engines making under 1000 hp. A carb like port injection can support thousands of horse power currently, but under 1000 hp street cars direct injection would make more power than either of those options on that same engine.

 

[vanrah]

Greetings Guys; Mr. Steel Chicken brought up a good point about helping keep the valves clean. And the fuel spray from Port Injection as a positive. During my four visits to Wegner's shop I was Mr. Question & they bestowed kindness on a fellow Ole' auto engine machinist. "Why are my Ls-2 pistons coated with carbon", 45,000 modest miles w/ a quarter quart of oil use per 1500 miles? I was told that the Ls-2 & another Ls variant (Lq 9 ??) have a "Very Poor" valley baffles & a Excellent vacuum source behind the TB. Hence they suck oil as most know into the intake (that's like in "manifold", as some younger fellas don't know the difference between a intake & a air-filer box-inlet!). If it wasn't for the injectors spraying on the valves they would of been coated in an oily carbon mess also. The fix is don't vent the valley plate vent hole to a "High" vacuum source & reduce piston crown carbon build up. So I guess we should like our nozzles spraying on our valves! Ole' Bob. Ps; Picture of said pistons (the red oil is Marvelous Mystery oil I placed for cylinder-ring protection) & 2 catch cans, one for the valley plate now venting into the air box (reduced vacuum). Old picture to atmosphere. The other taking vapor from Both value covers into the can and also venting into the air-box. So far I'm just catching brown water vapor.

 

[hadagto]

You should have seen how clean my stock ls1 was when I pulled it out. Ethanol and proper crank case ventilation goes a long way. Ethanol with direct injection helps a bunch even though it doesn't spray the back of the valves.

 

[Reaperhwk]

I own a Tahoe with direct injection. Valves were so dirty at 100k miles I had to pull the intake and walnut blast it clean. Now running a catch can to prevent it.

 

[hadagto]

Boost activated port injection?

Normal driving and low boost is direct injection and then when you get into high boost the port injection kicks in...LOL.

 

[Juniorss]

Port injection is becoming quite popular with the ZL1 crowd. I am most likely going to trade my SS 1LE in for one in 24 which is rumored to be the last year, so I keep tabs on the modding. On the ZL1, the high side is at its limit before going full E85 on a stock car. Previously you had to do a HPFP and a set of DI injectors, now you can put in the PI system which is more or else plug and play as far as the install goes.

As for boost activated PI, that is basically the theory behind it. I forget what it reads, but the PI kicks on at a certain point.

 

[hadagto]

Port injection is becoming quite popular with the ZL1 crowd. I am most likely going to trade my SS 1LE in for one in 24 which is rumored to be the last year, so I keep tabs on the modding. On the ZL1, the high side is at its limit before going full E85 on a stock car. Previously you had to do a HPFP and a set of DI injectors, now you can put in the PI system which is more or else plug and play as far as the install goes.

As for boost activated PI, that is basically the theory behind it. I forget what it reads, but the PI kicks on at a certain point.

Absolutely, but not cheap. Port injection setups for those are $6500+ depending upon the kit. From what I've seen at the 1000 rwhp level they can usually only handle 35%ish ethanol before the duty cycle gets super high. Alot of people that don't want the expense of port injection run methanol injection instead. Much cheaper and steam cleans things very well as well as the cooling and octane boost.

 

[MuhThugga]

I never paid much attention to the Gen V engines because GM hasn't put them into anything that really interested me.

I saw a thread on LS1Tech about bolting Gen V heads onto LS engines. It is an interesting thought, but after you purchase all of the needed components like the DI injector plugs, a swap-specific camshaft, swap-specific headers, and an LT intake manifold with injector bungs, plus the heads, you're looking at being able to purchase a rather stout set of aftermarket LS heads. One thing I didn't know about the Gen V head is that the exhaust port has a wonky bend in it. Edelbrock actually fixed the bend in their head design by moving the exhaust port 1.5":

 

[hadagto]

Ls7 heads with the valve issue taken care of would be ideal if you have the bore to use them. I'm not sure, but I bet someone even makes an aftermarket ls7 style head for smaller bores.

 

[MuhThugga]

Ls7 heads with the valve issue taken care of would be ideal if you have the bore to use them. I'm not sure, but I bet someone even makes an aftermarket ls7 style head for smaller bores.

Yeah, I think Mast makes a small bore LS7 head, and Engine Quest now makes an LS3 head with LS7 intake ports. The EQ heads retain the 15° valve angle, though.

 

[Juniorss]

Absolutely, but not cheap. Port injection setups for those are $6500+ depending upon the kit. From what I've seen at the 1000 rwhp level they can usually only handle 35%ish ethanol before the duty cycle gets super high. Alot of people that don't want the expense of port injection run methanol injection instead. Much cheaper and steam cleans things very well as well as the cooling and octane boost.

I am not too sure what the labor is to install, but Too High PSI is the current popular PI kit. The plates are about $800, the controller is about $1,100 and the injectors are about $700, so less than about $3,000 in parts. Obviously you will have to do some pluming to get fuel to it, as well as some tuning.

Meth is great until it fails. My dad had a Supercharged C6, and I prayed it worked when getting into boost. Id much rather have the correct fuel system compared to a band aid fix.

 

[hadagto]

I am not too sure what the labor is to install, but Too High PSI is the current popular PI kit. The plates are about $800, the controller is about $1,100 and the injectors are about $700, so less than about $3,000 in parts. Obviously you will have to do some pluming to get fuel to it, as well as some tuning.

Meth is great until it fails. My dad had a Supercharged C6, and I prayed it worked when getting into boost. Id much rather have the correct fuel system compared to a band aid fix.

I wasn't including labor I do all of my own installs/tuning. The kits I've looked at are much more $$$. Not something to cheap out on, but new Zl1's aren't cheap so if you can afford one of them you can afford the proper fuel system.

Funny thing is you hear a lot of people on the internet talk about meth failing who have never actually had a meth kit fail or even know anyone personally who has. People just repeat things they hear on the internet and if it gets repeated enough than you know...

You know funny thing number two is that the same people use the same pressure switches and parts to turn on the secondary fuel system or additional second/third fuel pumps as you use in a meth injection kit.

Meth isn't a band aid it's an excellent fuel source with high octane and insane cooling effects. I've been running ethanol as a primary fuel system and added meth injection on top of it a few years ago without issues.

$700 is cheap for injectors of course since it's a secondary fuel system you probably aren't needing as big of injectors. I'm using 1500cc deatschwerks injectors and they aren't cheap although cheaper than ID's. I don't like to cheap out on injectors if I can. Fuel pumps, fittings, and ptfe line add up quick as well. What happens if that controller fails?

Nothing is infallible. With meth there are safeguards you can tune in for IAT. Also, you make sure you have enough fuel pump/injectors to cover your needs without the meth. Meth is an additional cooling octane source for me. Not a band aid at all.