S/C'd 37VHR vs. 35HR?

bmarcinczyk14 · 09-23-2013, 09:15 PM

Out of curiosity, does the 370z generally respond better to FI (supercharged to be specific) than the older VQ35HR engines? For example, would it be safe to say if my 370z makes x amount of power at 11 psi, a VQ35HR would need over 11 psi to match x amount? Obviously comparing same kits, mods, ect. on both cars.

bacalhau1669 · 09-23-2013, 09:54 PM

Yes. The 37vhr flows better and is more reliable when boosted. Look around in the forced induction section here on the forum and you'll see some great results.

bmarcinczyk14 · 09-23-2013, 10:03 PM

i'm really eyeing GTM's 1.5 s/c kit. my goal would be 500whp, give or take a tad. i've seen people on the forum with this kit making 515whp, so i would think it's a realistic goal. would methanol injection and a fuel pump voltage stabilizer be required for my goal numbers?
EDIT: Fuel voltage stabilizer already comes with the 1.5 kit, my bad.

elperuano · 09-23-2013, 10:07 PM

Baer is the guy to ask.

bmarcinczyk14 · 09-23-2013, 10:10 PM

Quote:

Originally Posted by elperuano

Baer is the guy to ask.

Yup, that's one of the guys I saw had the same kit and over 500whp. I'll shoot him a PM.

bmarcinczyk14 · 09-23-2013, 11:02 PM

Out of curiosity again, what would you guys estimate 500whp on a mustang dyno equates to in crank hp?

Sent from my SCH-I535 using Tapatalk 2

bacalhau1669 · 09-23-2013, 11:05 PM

That's a big number you're shooting for. Not sure what kinda cars youve had previously, but nothing wrong with a 450whp, super reliable, safely tuned z either. You wouldnt need all the extra supporting moxs at 450whp either. That number seems to be the standard , so to say, when going FI.

phunk · 09-23-2013, 11:47 PM

VHR vs HR with the same supercharger... interesting conversation.

Think of PSI as your measurement of how much your engine is restricting the air leaving the supercharger. Take everything identical (piping, IC, pulley ratio, temps), so that precisely the same amount of air is entering both HR and VHR throttles. How much "boost" each generates indicates how well that engine flows. The lower the boost, the better the engine is naturally flowing.

There is reason to assume the VHR will flow better than the HR. With about 4.5mm greater stroke, the cylinders will be attempting to draw in 5-6% more air. Assuming the cylinder heads allow it, or at least some of it, evacuating the air backed up in the intake manifold more quickly into each cylinder's intake stroke will generate a lower boost pressure for the VHR engine. If the VHR cylinder heads (valves, lift and timing profile, as a package) were extremely restrictive, its possible to hurt airflow to levels lower than the HR despite the increase in displacement. This is unlikely, based on the type of power output we are seeing between the 2 engines comparatively.

The VHR engine has a higher static compression ratio. This means that, all other things alike, it will more effectively create power from the fuel/air mixture it is burning. So, at the same airflow from the supercharger, you will make more power through increased volumetric efficiency, despite the lower "boost" in the manifold.

So to answer your question, yes, if everything else is indentical, a HR will require more boost to generate the power a VHR does.

If NA vs NA one engine makes more power, the same one will pretty much always make more power boosted too.

phunk · 09-23-2013, 11:54 PM

Quote:

Originally Posted by bmarcinczyk14

Out of curiosity again, what would you guys estimate 500whp on a mustang dyno equates to in crank hp?

Sent from my SCH-I535 using Tapatalk 2

There is no accurate conversion for this. Generally we see about a 40-50hp loss between Nissan's claimed 332hp and WHP measurements.

So whatever you dyno at the wheels, you could safety estimate an extra 40-50hp at the engine. It could be a little more.

Alkatraz · 09-24-2013, 08:18 AM

Quote:

Originally Posted by bmarcinczyk14

Out of curiosity again, what would you guys estimate 500whp on a mustang dyno equates to in crank hp?

Sent from my SCH-I535 using Tapatalk 2

15-20% would be a reasonable ballpark figure for drivetrain loss.

bmarcinczyk14 · 09-24-2013, 08:22 AM

Quote:

Originally Posted by bacalhau1669

That's a big number you're shooting for. Not sure what kinda cars youve had previously, but nothing wrong with a 450whp, super reliable, safely tuned z either. You wouldnt need all the extra supporting moxs at 450whp either. That number seems to be the standard , so to say, when going FI.

The 370z is the fastest car I myself have owned. I also, however, have owned sport bikes and driven a built 911 turbo and c6 z06, so I'm no stranger to speed. By reading up on FI, it seems the 37VHR engine can handle 500whp safely on stock internals, as long as your install and tune are good. And as natural man instinct, I want the most power for my money possible, safely of course. And it doesn't look like I'd really need anything extra from the stage 1.5 kit, Baer confirmed he did not need extra. His aggressive tune is whats making him the power. I'm sure it's also safe and reliable as well. I may consider Methanol Injection to be on the safe side, and also help make more power.

09-23-2013, 09:15 PM	#1 (permalink)
bmarcinczyk14 Track Member Join Date: Jul 2009 Location: Chicago Posts: 505 Drives: 2010 370z 6spd Sport Rep Power: 16	S/C'd 37VHR vs. 35HR? Out of curiosity, does the 370z generally respond better to FI (supercharged to be specific) than the older VQ35HR engines? For example, would it be safe to say if my 370z makes x amount of power at 11 psi, a VQ35HR would need over 11 psi to match x amount? Obviously comparing same kits, mods, ect. on both cars. __________________ '10 370z -- '09 Ducati 848 -- '05 Kawasaki 636 Track Bike -- '02 Sentra SE-R Spec V

09-23-2013, 09:54 PM	#2 (permalink)
bacalhau1669 Base Member Join Date: Jun 2013 Location: palm coast Posts: 86 Drives: 2013 Base Sport Rep Power: 11	Yes. The 37vhr flows better and is more reliable when boosted. Look around in the forced induction section here on the forum and you'll see some great results. bmarcinczyk14 likes this.

09-23-2013, 10:03 PM	#3 (permalink)
bmarcinczyk14 Track Member Join Date: Jul 2009 Location: Chicago Posts: 505 Drives: 2010 370z 6spd Sport Rep Power: 16	i'm really eyeing GTM's 1.5 s/c kit. my goal would be 500whp, give or take a tad. i've seen people on the forum with this kit making 515whp, so i would think it's a realistic goal. would methanol injection and a fuel pump voltage stabilizer be required for my goal numbers? EDIT: Fuel voltage stabilizer already comes with the 1.5 kit, my bad. __________________ '10 370z -- '09 Ducati 848 -- '05 Kawasaki 636 Track Bike -- '02 Sentra SE-R Spec V Last edited by bmarcinczyk14; 09-23-2013 at 11:04 PM.

09-23-2013, 11:02 PM	#6 (permalink)
bmarcinczyk14 Track Member Join Date: Jul 2009 Location: Chicago Posts: 505 Drives: 2010 370z 6spd Sport Rep Power: 16	Out of curiosity again, what would you guys estimate 500whp on a mustang dyno equates to in crank hp? Sent from my SCH-I535 using Tapatalk 2 __________________ '10 370z -- '09 Ducati 848 -- '05 Kawasaki 636 Track Bike -- '02 Sentra SE-R Spec V

09-23-2013, 11:47 PM	#8 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,655 Drives: 370 Rep Power: 944523	VHR vs HR with the same supercharger... interesting conversation. Think of PSI as your measurement of how much your engine is restricting the air leaving the supercharger. Take everything identical (piping, IC, pulley ratio, temps), so that precisely the same amount of air is entering both HR and VHR throttles. How much "boost" each generates indicates how well that engine flows. The lower the boost, the better the engine is naturally flowing. There is reason to assume the VHR will flow better than the HR. With about 4.5mm greater stroke, the cylinders will be attempting to draw in 5-6% more air. Assuming the cylinder heads allow it, or at least some of it, evacuating the air backed up in the intake manifold more quickly into each cylinder's intake stroke will generate a lower boost pressure for the VHR engine. If the VHR cylinder heads (valves, lift and timing profile, as a package) were extremely restrictive, its possible to hurt airflow to levels lower than the HR despite the increase in displacement. This is unlikely, based on the type of power output we are seeing between the 2 engines comparatively. The VHR engine has a higher static compression ratio. This means that, all other things alike, it will more effectively create power from the fuel/air mixture it is burning. So, at the same airflow from the supercharger, you will make more power through increased volumetric efficiency, despite the lower "boost" in the manifold. So to answer your question, yes, if everything else is indentical, a HR will require more boost to generate the power a VHR does. If NA vs NA one engine makes more power, the same one will pretty much always make more power boosted too. bmarcinczyk14 and DEpointfive0 like this. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph

09-23-2013, 10:07 PM	#4 (permalink)
elperuano A True Z Fanatic Join Date: Oct 2011 Location: Southwest FL Posts: 1,374 Drives: G37S Rep Power: 28	Baer is the guy to ask.

09-23-2013, 11:05 PM	#7 (permalink)
bacalhau1669 Base Member Join Date: Jun 2013 Location: palm coast Posts: 86 Drives: 2013 Base Sport Rep Power: 11	That's a big number you're shooting for. Not sure what kinda cars youve had previously, but nothing wrong with a 450whp, super reliable, safely tuned z either. You wouldnt need all the extra supporting moxs at 450whp either. That number seems to be the standard , so to say, when going FI.