Pros & cons of my Turbo Vs. N/A motor.

[nitrorocket]

I though I would list my experience with my turbo engine compared to my previous motor, pro’s and con’s. I figured some might take this info as good knowledge for there own future projects. It is info you don’t see first hand anywhere and stuff a lot of people don’t realize.

Old motor:

- 427” Tall deck dart block SBC
-4” stroke
-6.125” rods
-Solid roller .690 lift cam, 265 @.050
-10.5:1 compression
-18 degree Dart heads with 2.15/1.625” valves
-1.7:1 shaft rockers
-1.625” valve springs with 750 lb. open pressure!
-Custom single plane “053” Nascar intake
-Accel Gen 7 fuel injection & 83 lb./hr injectors
-Approx. 650 hp at 7000 rpm.

This motor costs approximately $20,000 to duplicate. It was built to be a “Street” driver motor. The engine was driven a about 3000 total miles over the few years I had it along with a few drag strip passes. It sounded wicked and had gobs of power for a N/A motor. The fuel injection was a nice feature for startup drivability and consistency, but added huge cost to the engine.

Positives of the motor were the sound; it sounded awesome, had a real nice rumble and had about a 1000 rpm idle. The motor would start right up at the turn of the key at any temp, never had to touch the gas. The motor was also a simple standard SBC based motor that was very easy to work on.

Negatives were the cost, $20k is way too much money for a motor that is not for racing and gets street driven. Motors wear out, and to wear out a $20K engine by cruising back and forth to a car show did not make sense! The motor got very poor mileage. I was getting right about 10 mpg if I drove nice, if I went on beat runs, I could burn a half tank within 10 miles. The motor was also very high maintenance. Most people do not realize until you own one how much this can limit you and cost. I had to replace the valve springs, rocker bearings, and lifters every 1500 miles! At $900 in parts alone, this was not fun.

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New turbo motor:

-347” Aluminum block LS1
-Stock crank
-6.125” rods
-Hydraulic Roller .581 lift, 224 @ .050
-8:1 Compression
-Factory heads with porting
-Dual valve springs
-Stock intake
-Stock computer
-Makes about 1000 hp at 6000 rpm

Turbo setup:

-Twin 61 mm GT35 Ball bearing turbos
-1.75” stainless headers
-Twin Racegate Wastegates
-1 50mm Blow off valve
-1500 CFM air/air intercooler

I have half into this motor over what my 427 cost. This motor is actually a real “street” motor. I can drive cross-country back and forth until I run out of gas money! It idles at 800 rpm, can go on a cruise without attracting Police officers, and is quiet. I have driven the motor about 1500 miles along with a dyno pull and strip pass so far with good results.

Positives of the motor are the mileage. The setup is getting about 15-city mpg and should get about 20-mpg highway if I drive nice. The motor is quiet enough to finally hear my radio and talk with my family! Being that the motor is basically just a ls1 with turbos on it, it runs drives, starts, and does everything a regular ls1 does. That is REAL nice, I don’t have to worry about maintenance and getting stranded over some rare expensive race part failure. The power is more then a street car EVER needs.

Negatives are the complexity of the setup. On top of the simple little LS1, is a lot of plumbing. There are lines all over for oiling, cooling, and exhaust that were not easy to route cleanly. The other negative is that I had to design and build the entire setup myself instead of buy parts off the shelf. This added a lot of time to the build. I had one turbo failure from a faulty turbo that resulted in the purchase of the two ball bearing turbos, that failure will not happen again. This may sound weird but another negative is the power. If you are not careful it can get out of hand real fast. With each ¼” of throttle pedal travel equaling about 100 hp, if you go over a bump in the road or slide in your seat and wiggle the gas pedal…. The tires will spin.


Conclusion…. Forced induction, whether it be turbo’s or a supercharger, is the BEST way to make reliable power. You can never have a motor with all the benefits without it. It is also much cheaper then a big horsepower N/A motor. That was a factor that made me go the F.I. route.

[UnderPSI]

:D <------ Thats my contribution. I love that car. Lots of work pays off. That car is clean and done right. :thumbsup

[Yooformula]

I can take off your hands if its too much for ya. That might be a positive for you....lol

[HAMRHEAD]

Turbo instead of supercharger. With that said, there will be more money to spend. If you want to make that kind of power ditch the stock computer. It will do it but doing it doesn't always get it done right. Go with a BS3. Also I don't know if you are using parts from your other set up but don't forget your fuel system. I went with 96lb injectors for a similar set up. What year car do you have?
FI is better than NA but it can be very costly as well and there is a lot of time spent fabricating and tuning.
Also with the BS3 you can run a seperate set of injectors easily. Then you can have them connected to a fuel cell to run c16 or similar for when the car reaches a certain point of boost and needs higher octane fuel. Just a thought!

Good luck

[HAMRHEAD]

Never mind abou the year of the car I just saw it. Maybe if I open up my eyes a little! To damn tired need to come home and get some sleep!

[BAD LS1]

Well i think Nitrous oxide is a serious contender in this topic and meets about 99% of the forced induction engine rules of thumb. The only disadvantage is that it runs out.

My car shakes down 19 mpg with mixed driving and a fair amount of beating during that tank of gas, so all hwy, and no beating id bet on close to 25mpg. with a .600/.600 237/242 cam, no surging, stalling, racing and drives fine in stop and go traffic, sans for ON/OFF switch clutch that gets old.

When i had the dryshot on, there was no extra tweaking that had to be done in prep for spraying it with a 130 shot. I pre programmed into the timing table at .72g/cyl and better it ran 24* timing and then when it was on motor it would never see that high of load, so it would operate at about 30* WOT timing. The MAF would add X amount of fuel for the given extra density when spraying, all was good at about 12.2AFR on the jug, 13.0 on motor.

I have absolutley no doubt in my mind my car would have gone 130 trap speeds on street tires with that same 2.0 60 foot provided the maf didnt fail at the track, i could spray it earlier than 2nd gear, and it didnt run out of 4th gear about 60 foot before the traps. But went 125 with all these things wrong. Not bad for about only 530 rwhp on the jug.

Now i have yet to play with lean cruise and DFCO to try and squeak more out of it, but i just make sure the trims are + - 1 when cruising at hwy speeds and i have about 45* of advance during cruise. that seemed to help quite about and stretched how far i could go on a tank by 25 miles with roughly the same driving habits.

Now the direct port requires a tune for when i know im gonna spray it, much like a race tune-up for forced induction cars, mix of race gas, AFR tuning and timing tune different from NA. But the direct port is like a whole diff animal in terms of feel and hit comapred to the prior dry shot. But who cares? once the tune is done, it takes 30 seconds to load it, and your in race mode, add a few gallons of race fuel and slicks and skinnies and its ready to go.

Maybe twoards the end of summer as i get mine dialed in we could have a comparison? Its a known fact you would still have about a 100 RWHP up on me with me on a 200 shot.

long trip, gas mileage, and the track?

[nitrorocket]

I get alot of questions on how the car is. I put this post up to kinda show people through my experience with both N/A and turbo, what my pros and cons are. :)

I might hit the chassis dyno again just to "Prove" That I have over 800 RWHP right now on 93 octane. :thumbsup Otherwise I am super happy with the car as is. I am hoping to get close to the 150 mph mark when I hit the track again.:thumbsup

[BAD LS1]

Thats cool, i wasnt "trying" to sound like a c0ck or nothing if i came off that way. it was all friendly.

[nitrorocket]

I used to run A 250 shot on an old 383 I had, but like you, I could never keep a bottle full!:thumbsup :crying

[HAMRHEAD]

That was the only problem I had with my N2O setup. I hated refilling the bottle all the time.