Nissan 370Z Forum - View Single Post

Gearhead51 · 11-30-2011, 02:23 PM

Good luck with a N/A build. I, for one, am quite impressed with the factory output of this engine. Considering it passes emissions and has a warranty is even better still. I looked up a '68 Charger with 426 Hemi: 0-60 in 5.3 sec, 1/4 mile in 13.8 sec @ 105mph. I ran a 13.8 sec @ 102mpg in my girlfriends 370 with a 7AT. The numbers of the Z look as good with much less engine, and it can rail through the mountains. BTW, I love American muscle.

Remember, in a perfect, frictionless universe you have to burn twice the fuel to make twice the power. To burn twice the fuel, you have to ingest twice the air. If you add 10% to the displacement, you still have 90% to go. 10% better VE? That will require more extensive headwork after a displacement increase due to larger cylinders pulling air through the same number of ports. Ok... If you get that, you are getting closer. Of course, variable valve systems are not necessarily an enemy... unless peak HP is all you are after. They give you good VE at low RPM and good VE at high RPM. Are you planning on a custom stroke? If so, is that with a custom crank (will it fit?) or by shortening the rods (making the rod ratio worse is detrimental to engine life.). 15% higher RPM? Rods really don't like tensile loads. They are typically many times stronger under compression. Can it be done? Perhaps. Will anything be left of the engine you started with? Probably not.

From somebody that was building imports before imports were cool, I'm impressed with what these engines can do. Back in the day, we had 1.3L rotaries with 140HP and we were hot stuff. We could port them and squeeze them to 170 by porting and increasing VE, never pass emissions, killed mileage, and lost low end power. Custom peripheral port engines were close to $10k. So we did that. Made almost 300hp, wouldn't idle under 1300RPM and made power 6500 to 10,000 RPM. Forget A/C, power steering, picking up a woman, and getting to work on time because it was reliable. The car was clearly a dude magnet. Then we found turbos.

The same 1.3L displacement that once made 140FWHP now makes 425RWHP in my RX7. FI CAN double or triple the HP of an engine of a certain displacement. While I'm another person giving you an answer you don't want to hear, FI is certainly the easiest way to make reliable power. In our hypothetical perfect world, 15lbs of boost doubles the VE of the engine... doubling the power.

Sure, we are bolting turbos and superchargers on bone stock engines... or built engines. Why is that necessarily a bad thing? Many turbo engines run lower compression, so if you want to do it "right" toss a set of low comp pistons in. Since rods are stronger under compression, the prefer the additional stress of FI over the tensile loads of RPM. If you go FI and don't have a detonation issue, it's not overheating (we ARE making more power than stock, so we have to reject more heat... this is the case with NA or FI power), cranks every time, acts like a civilized vehicle when not on boost, and has a/c what is the problem?

Personally, I love the sound of turbos whistling and wastegates opening. Even in the American muscle world, when you want BIG power, you go FI.

11-30-2011, 02:23 PM	#58 (permalink)
Gearhead51 Base Member Join Date: Jul 2011 Location: Gainesville, GA Posts: 17 Drives: Which one? Rep Power: 14	Good luck with a N/A build. I, for one, am quite impressed with the factory output of this engine. Considering it passes emissions and has a warranty is even better still. I looked up a '68 Charger with 426 Hemi: 0-60 in 5.3 sec, 1/4 mile in 13.8 sec @ 105mph. I ran a 13.8 sec @ 102mpg in my girlfriends 370 with a 7AT. The numbers of the Z look as good with much less engine, and it can rail through the mountains. BTW, I love American muscle. Remember, in a perfect, frictionless universe you have to burn twice the fuel to make twice the power. To burn twice the fuel, you have to ingest twice the air. If you add 10% to the displacement, you still have 90% to go. 10% better VE? That will require more extensive headwork after a displacement increase due to larger cylinders pulling air through the same number of ports. Ok... If you get that, you are getting closer. Of course, variable valve systems are not necessarily an enemy... unless peak HP is all you are after. They give you good VE at low RPM and good VE at high RPM. Are you planning on a custom stroke? If so, is that with a custom crank (will it fit?) or by shortening the rods (making the rod ratio worse is detrimental to engine life.). 15% higher RPM? Rods really don't like tensile loads. They are typically many times stronger under compression. Can it be done? Perhaps. Will anything be left of the engine you started with? Probably not. From somebody that was building imports before imports were cool, I'm impressed with what these engines can do. Back in the day, we had 1.3L rotaries with 140HP and we were hot stuff. We could port them and squeeze them to 170 by porting and increasing VE, never pass emissions, killed mileage, and lost low end power. Custom peripheral port engines were close to $10k. So we did that. Made almost 300hp, wouldn't idle under 1300RPM and made power 6500 to 10,000 RPM. Forget A/C, power steering, picking up a woman, and getting to work on time because it was reliable. The car was clearly a dude magnet. Then we found turbos. The same 1.3L displacement that once made 140FWHP now makes 425RWHP in my RX7. FI CAN double or triple the HP of an engine of a certain displacement. While I'm another person giving you an answer you don't want to hear, FI is certainly the easiest way to make reliable power. In our hypothetical perfect world, 15lbs of boost doubles the VE of the engine... doubling the power. Sure, we are bolting turbos and superchargers on bone stock engines... or built engines. Why is that necessarily a bad thing? Many turbo engines run lower compression, so if you want to do it "right" toss a set of low comp pistons in. Since rods are stronger under compression, the prefer the additional stress of FI over the tensile loads of RPM. If you go FI and don't have a detonation issue, it's not overheating (we ARE making more power than stock, so we have to reject more heat... this is the case with NA or FI power), cranks every time, acts like a civilized vehicle when not on boost, and has a/c what is the problem? Personally, I love the sound of turbos whistling and wastegates opening. Even in the American muscle world, when you want BIG power, you go FI. __________________ His: '94 RX7 Gotham Racing Street Port 3mm seals, Power FC, GR67 single (T04R), twin Tials dumping behind front tire, Tein coilovers w/ EDFC shocks, etc... Hers: '09 370Z Touring, 7AT, all stock (for now)... '04 Silverado Z71 for sale.