EFI SBC vs LS Motor
 

Just looking for some specifics on why to do one vs the other. Currently I have a 350 SBC & T-10 with the following mods:

• Eldelbrock TEC 200 Aluminum Heads
• COMP Cam 12-612-5 Solid Lifter Cam
• Roller Rockers
• Ceramic Coated Headers
• Holley Competition 750 cfm
• MSD Ignition
• Super T10 4 Speed Transmission
• Center Force Clutch
• Scatter Shield
• Hurst Comp Shifter
• OEM Forged Crank
• OEM polished rods
• TRW pistons w/ floated wrist pins
• Balanced rotating assembly
• ARP Head Bolts & Fasteners

So I've been really interested in doing an LS swap, even have tossed the above setup for sale, but a friend says since I've already got some decent parts on this motor why not just EFI it?

Now my goal is 700whp with a blower - granted this will be a while down the road, one step at a time.

From what I've read, with no specifics other than newer technology, the LS motor does everything better. From fuel economy to making power and the important one drive-ability. A big one for me is the reliability and turning the key and having it start, without pushing the pedal 4 times etc. Yes the 350 has never let me down but I'm nervous every time it cranks for a min, ha!

So why not do an intake manifold and EFI on the 350 SBC? Why should I swap to the LS?

To you guys that have done the EFI on the 350, what parts have you used?

Thanks!!! :y0!:

I am no expert, but from what I have read, it seems to me that when it comes to breathing, the LS engines are really more akin to a Big Block, and that's the big difference between the old Small Block and the LS engines.

You can make the same power in a more reliable package with an Ls.

The irony is that with all the interest in LS conversions, the SBC parts are becoming very inexpensive. While I continue to monitor LS conversions, at least for the forseeable future I will be running a SBC. I am considering a throttle body EFI to replace my Holley double pumper at some point.

I've thought about it. If you do this you still have to do all of the other 'fuel' parts. Tank/pump/regulator/lines etc. At which point if you decide to go LS it'll already be done, ya? Or am I missing something here?

I thought about converting my built SBC over to fuel injection too, or even procharging it but my compression is a little to high at 10:1

It's like Todd said, the LS does it more reliably. Even with your goal of 700whp, the LS will be more reliable though it's arguable what constitute reliable at that power level. If you were wanting a lower power level, say 500 or so at the wheels, I'd say stay SBC because with a blower that's not difficult or really even pushing limits and a good EFI system will allow for good drivability.

The other thing to keep in mind when building a forced induction car is where the power comes on. As an example, to me, a Procharger is a terrible choice for a pro-touring car or really any car not being drag raced. Go drive one and you should realize very quickly that it does not produce a linear power band and they have terrible lag(I know nothing about their new intelligent design so maybe that's changed) which is not enjoyable when going on and off throttle and around corners. So achieving your goals with boost and how much boost will be needed also has to be taken into consideration. At 700whp, the LS will do this better as well needing less boost which will allow for an engine that isn't piss poor when not under boost.

I would recommend building towards the ultimate goal from the get go or else you'll be redoing lots of stuff. If going for 700whp is required to you, get an LS now and call that part done.

Thanks for the response.

However, I'm not sure about your 'lag' description. Superchargers are far more linear than a turbo is, am I missing something here? Is it the that style supercharger, a Procharger that's not as linear?

I've own supercharged and turbocharged vehicles, mostly BMW's and the supercharger on that one was far more linear and constant than the turbo. On a road course you better know exactly when that turbo will spool or you'll be going sideways.

Correct me where I'm wrong! Thanks!

Yes, it's because it's a Pro-Charger. They need RPMs to build boost just liek a turbo typically does. A Whipple, Magnacharger/Harrop/Eaton, and Kenny Bell blower won't act like that typically(the wrong cam or too big of a blower can cause some lag though). They are known as positive displacement blowers. They are listed in a volumetric size because that's the equivalent "displacement" they add to a motor. Basically, they make the motor act as if it's bigger than it really is from the throttle response to how much power they end up making. However, a Pro-Charger makes great power and is an excellent supercharger. It's just not making power where or how it needs to be made in order to make a good pt style car. That's my point, be careful where and how you make your power when reaching for that 700whp goal. That's why I think you'll need to plan your build from the get go if 700 is the goal. Last thing you'll want is a 700whp motor that is no fun to drive the way you want or intend to drive.

500-600 is much easier to build in stages starting with NA because it's fairly easy to reach those numbers reliably with low boost levels. 700 at the wheels puts you at about 850 flywheel. Going from NA to that level boosted reliably is not so easy due to the increase in boost needed among other things. This is of course my opinion. I'd highly recommend you work with a builder before you do anything if seriously reaching for the 700whp mark. I'd also recommend you focus more on how you want the engine to respond and where the power is made than simply shooting for a number if enjoying the drive is the main goal.

A car for you to check out that may be of interest is one built by member RS302 or something like that. He started with a 1st gen that was Ford 302 powered. Once he blew that motor, he went to an LSx with twins. The throttle response is unreal on that car. I love it. He makes great power and runs it on 87 octane. It's a neat build.

There's just no comparison between a SBC and an LS motor.... if you're looking for a great "up grade" from what you have now - just buy an LS motor or be sorry you wasted your money on old skool stuff. You'll be money ahead with the LS.



The HP figures you're throwing around require a LOT more expense than just the motor. I won't waste my time explaining this now - cause you're not there... but anyone on here will tell you this.

Thanks for the info guys, didn't know that about the ProCharger, good to know!


It sounds like I might end up going turbo after all. Those other style chargers introduce a decent amount of heat/soak issues due to their placement for the style driving I do, sounds great for 1/4 mile though but I don't do that except for fun with friends. I'm for sure not chasing any 1/4 numbers though I'd much rather spend my time on the street and road courses.

Sounds like for what I want I do just need to go ahead with an LSX style swap and well my built 350/tranny.

Good info! I'll look more into the comparison of procharger vs turbo setup now.

I've very familiar with what would need to be done to the motor, especially for the type of driving and power, but had no clue of that ProCharger and the way it reacts. We'll see if I decide to built the motor or not for whatever I decide. After this research I'd been thinking of doing everything else, other than the motor, first. Mini-tubs, front and rear subframes etc. Decisions decisions!!

Thanks!

That "heat soak" issue you mention certainly hasn't played out in the last few Corvettes and Cadillacs that are running factory roots style blowers.

For road courses or 20-30min track sessions? Is this the new LS9 motor you're talking about?

LS9 or LSA -- either one.

Ya, won't be going with one of those motors though heh

I've had three Procharged builds, none of them had any lag. Instant boost on WOT, maybe not max boost immediately, but enough to blow the tires off. Definitely not laggy like a turbo setup with the wrong or improperly sized turbo would have. And far less heat management issues than a front mounted turbo setup. Personally, I'm sold on the roots type blowers now for true instant boost and driveability. They may not make as much HP as turbos, but far easier to package and maintain, far less heat issues to deal with.

Camcojb you say less heat to maintain in a roots style, how so? Everything I read says otherwise. They sit on top the motor and heat soak, from the drag strip to dyno pulls and for sure road courses. Have things changed recently? I'm not saying you're wrong just lookin for info!

Turbo heat can be dealt with decently easy. From what I've seen a roots style charger is harder to ditch the heat.

Oh and yeah, not to worried about raw hp numbers, more FUN and drivable for both street and some track days!

**Some sexy engine bays in your sig link!!**

Not talking heat soak, talking heat management. A front mounted turbo(s) will give you more heat management issues than any blower, at least they always have with mine. Air temps can suffer with a roots blower vs a turbo, but a good intercooler/heat exchanger/pump setup with a cool air intake source can improve that a lot. Under hood temps, oil temps, and even water temps are more of an issue with turbos than blowers in my experience. You've got all that extra exhaust plumbing as well as the turbo housings adding heat. The engine oil is further heated by going through the turbos, and water also if they're liquid cooled. Plus the intercoolers for turbos are usually much larger and thicker than the heat exchangers for a blower, so they affect the radiator airflow and cooling. Yes, they can be engineered to work with all of this, but to me the blowers are easier to deal with, have fewer heat management issues to address, and easier to bolts on (less fabbing). Doesn't mean that I don't like turbos, because I do. Plus after riding in "Mayhem" I just think that combo on the street or track is more than enough for pretty much anyone, even a guy like me that's had 1000 HP setups before.

You should go through the Mayhem build thread. Mark and I believe Brian Thompson, who built the engine, really give a lot of great info on heat management with the roots style blowers.

Maybe lag was the wrong term to use when talking about the Pro-charger but it's not as quick as a roots blower. I much preferred driving a Magnacharged vette to the Pro-charged ones even though the Pro-charged ones made more peak power typically. The torque band on a roots style blower is a lot better for street driving too. That's what really sells it for me.

I agree. :thumbsup:

Any boosted combination will have heat management issues to overcome whether it be under hood air temps with a turbo or intake air with a blower.
The problem with the roots type blowers available is the intercooler under the blowers don't allow enough water flow to efficiently keep up with the temperature rise running lap after lap on a road course. We've been doing some dyno testing with all the popular roots blowers out there and the only one we've found that has promise is the 4.0 whipple but even that one needs mods to the water fittings to allow it to pass enough water through it.
The 4.0 has a different set of problems, mainly the overall length with the drive and air intake makes it difficult to package in most cars. We've also found that even a 102mm throttle body is choking this blower and still shows vacuum behind the throttle blade. We are currently working on a shorter drive and air intake that uses twin 90mm throttle bodies that should cure that. The dyno mule made 962 hp with a 2.9L whipple but heat soaked badly, so we think we should be able to do the same with the 4.0L without all the heat soak since we can spin the blower slower and it has a better intercooler.

With all that being said, I don't understand why so many people concentrate on all these big peak power numbers when a higher average power number and a car with properly matched trans/rearend gearing will be faster.
My car was almost a full second faster than DSE's 70 camaro at LS Fest on the drag strip, same car, same track, same gearing and I'm giving up nearly 100 hp at the crank but because I built the engine to maximize it's power with that combination it's significantly faster.

At 500fwhp it would be cheaper to do a 383 rotating assy, port the heads/intake and buy a FAST 2.0.

At 700rwhp you need to go LS, and be prepared to spend some money. Another option for 700rwhp is a BBC.:)

While a BBC is sexy sounding I'm not sure I want the weight. If I do swap the motor I'll 100% go fuel injection too.

Basically what I have, 383 (10-8comp), Dart 210 (small port Job) Heads, Fast 2.0, about 400 rwhp (570 with a 200 shot of nos) through a automatic with a 3500 stall. Think with the right heads can get it to around 450RWHP, and still keep it road friendly. I have not had it dynoed since I installed the Fast 2.0, but it drives really nice, starts up on cold days without touching the throttle. (10.69 1/4 mile with carb no suspension tuning))

I agree a BBC would be too heavy. The real issue is which EFI system. Holley, FAST, MSD, who makes the best throttle body EFI? They all just keep getting better.

This question is in my opinion, comes down to who you ask. Reason I say that is I researched the same thing for months and had good/bad on all of them. Its really coming down to looking at what they all do, and put all the inputs together and chose your poison. I have the Fast 2.0, because I loved what I read. Its has been a small challenge so far to get it to being that "Plug and Play" as advertised, but right now its working good (didn't say great/awesome), but hopefully with more time it will be. Thats my 2 cents.

There's also the possibility of running a LSx PCM on the SBC. www.eficonnection.com has the setup.

It really can get confusing to decide which EFI system to utilize. I personally am in favor of the LSx PCM whenever possible. None of the aftermarket systems come close to having the level of investment in them that GM put into the LSx PCM. However, do you need all that the LSx PCM has to offer to achieve your goals? I've built EFI systems utilizing a L98 SD PCM. It worked great and this was just a few years ago. So, yeah, it gets confusing and difficult to decide.

What I would recommend is that you focus on achieving your power goals properly and reliably first. After all, EFI is not needed in order to achieve your power goals. Then, I would decide which EFI system to go with. Just factor the extra cost of EFI on the LSx engine into the initial cost since chances are you'll buy a pullout that has a perfectly adequate PCM already there.

Thanks for the link and the info. Just want to point out a few things with my build to help with more info.

I guess I shouldn't have really stated power as an overall goal. It'd be nice to have 700whp but I'm not 100% set on it, I'm not trying to hit a 1/4 mile goal or dyno # goal. This will be a street/road course/autocross car.

It sounds like you're suggesting that going EFI on the SBC will not take the same initial cost as going EFI on an LSx setup, why? The LSx will already have what's needed on the motor itself and the rest would be the same as going EFI on the SBC, no? Fuel lines, tank, pump, etc. Or am I missing something here? I don't want to run an external pump from the tank, so I'll be getting a new tank for that.

Now I'm actually leaning towards having someone re-tune my SBC and Carb setup and doing all my underbody first. I want bolt on subframe/suspension front and rear. Thinking of doing that first since I have an already decently solid SBC build. I think it's just not tuned correctly for it's new location (GA vs CA)

Oh and I do plan to run a GM ECU not an aftermarket/standalone unit. From the tuners I've spoken with I see no need to go aftermarket, both for N/A and boost applications.

Honestly, I forgot your initial question with my last reply. I was merely thinking power production.

You're correct about the other upgrades needed to supply an EFI engine. Those upgrades don't care what engine you're running. Fuel supply volume and pressure required dictates the fueling system mainly.

I'm actually doing my suspension and chassis changes first since I have a running engine. I figure it will be more fun to drive that way. It already moves on its own and I'm not trying to race anyone. Eventually, I'll start building the new engine after I finally decide which direction I'm going. So I certainly don't think that's an incorrect path to take.

The LSx PCMs read up to 3 bar I believe. That's 45 psi. 1 bar is approximately 15 psi. They make excellent PCMs for street boosted applications.

The 3 bar range is 0-100kpa vacuum and 100-300kpa boost, still 30psi boost is going to get the job done for most.

Really you could make 700rwhp on a basically stock LQ9 or LQ4. (just cam/springs/forced induction). If you want to be very safe about it then throw rods and pistons in any LS and it would make that power forever.

After running super reliable LS combinations for years I would personally never consider using a sbc or bbc again.

You give up some drivability with the 2.0.

I encourage you to download the software from all the different manufacturers and compare them for yourself before you buy anything.

Yes, I've done a few in the last year or so. There's one or two on here that I did via email.

I was all giddy when I got the chance to tune one for the first time. Saw all the advertisements etc. I though I would be impressed. Instead I was very disappointed.
Does it have some neat features? Absolutely, i.e. E85/Flex Fuel capability, traction control (although most say the MSD 7 one works better), self learning etc.

But it only has 2 transient fueling tables, most other systems have 4 or 5, very important for the ultimate in drivability, no secondary MAP sensor and the individual cylinder trim for fuel and spark is an all or nothing calibration. In other words, you can't tailor the individual spark and fuel by rpm and/or load so it's useless in most applications. Plus the self learning can cause problems, and that only saves the tuner an hour or so anyway.

Just remember one thing. Just because something is advertised the most doesn't automatically mean it will be the best. And especially lately I've heard their tech ain't all it's cracked up to be.

Most do the first four real well. However adding the fifth feature narrows the perspective field a bit. I'd say today the best option that covers all five features listed would be the new AEM Infinity and maybe the Holley Dominator.

Hope this helps.

Thanks Mark! :cheers:

While we're hijacking...

Where does the Holley HP EFI fall in your ranking, or do you have experience with that system?

Thanx!

Imo better than the FAST 2.0.

OK, any feedback on Edelbrock Pro Flo 2? :)

Thanks,
Don