G37 Sedan, max possible HP N/A

[Fahad]

What kind of HP I can get from a G37 Sedan 6 speed man. in N/A form after having a fully built engine?

And what should I expect at the 1/4 mile?

Thanks,Fahad

[suby01]

whats fully built?

[Fahad]

Heads, cams, intake and any thing that give good power.

Thanks,

[Sentientbydesign]

You could probably get around 330-335 to the wheel, but that's just an estimate. The car hasn't been out long enough to see what people have done with it.

It it manual or auto?

[Fahad]

It will be manual.

What about the G35?

We have a 2007 G35 Sedan Auto stock, we ran 13.7.

I am planning to buy a G37 sedan, If I can get 400 WHP N/A

[Sentientbydesign]

I am planning to buy a G37 sedan, If I can get 400 WHP N/A

Won't happen unless you're running nitrous, in which case, it wouldn't be N/A. You're asking for 108 hp per liter N/A.

[tollboothwilley]

Well...if you build it fully...hrmm

for the 3.5 there is a 4.2L stroker kit. I bet for the 3.7 they will come out with a 4.4 or 4.5 stroker kit. That fully built with a lot of mods I bet you will get close to 400.

The question just comes down to how much you are willing to spend, like always!

[C-Kwik]

Won't happen unless you're running nitrous, in which case, it wouldn't be N/A. You're asking for 108 hp per liter N/A.

Actually hes trying to pull off 400 WHP. Assuming a 15% drivetrain loss, that's 127 HP per Liter. That's gonna be pretty hard to do without some serious reengineering (Read: $$$$$$$$). The engine has to be built to rev higher and breath well at high RPM's. Higher compression would help, but if limited to pump gas, it could be a problem. You could punch out the block and/or stroke it, but then you start playing with larger piston masses and higher piston speeds (relative to engine speeds). It could be done. But its really going to be a matter of money. For that kind of power, better to go with forced induction.

[Fahad]

I am looking to spend $10,000 including suspension, exhaust and trans upgrades.I want to run on 91-93 octane.

Thanks,

[Sentientbydesign]

I know this is NOT what you want to hear, but you'll have to go supercharger or turbo in order to see those numbers on pump gas. Realistically your budget could include all of that if you do some of the work yourself.

[tollboothwilley]

I am looking to spend $10,000 including suspension, exhaust and trans upgrades.I want to run on 91-93 octane.

Thanks,

I think to get 400 WHP for $10,000 you'll have to go FI and will have to do MOST if not ALL the work yourself.

[Fahad]

I am really not into FI.

I am planning to drop the car at a shop in Texas or Florida to do all the job then ship it to Saudi Arabia.

Do you recommend good tuning shops in these states?

Thanks,

[tollboothwilley]

I know there are a few good shops in Georgia for the G/Z. Some FL people will chime in hopefully. They may know of a good shop there. A good tune with engine mods/intake/headers/cats/exhaust would do a lot for the car. the Tune is a must, but I don't think you'll push 400 WHP on your budget.

[C-Kwik]

I am looking to spend $10,000 including suspension, exhaust and trans upgrades.I want to run on 91-93 octane.

Thanks,

To be quite frank, I doubt $10K would get you anywhere near your goal even if you dumped all of it into the engine. Dimensionally, the VQ is not suited to the kinds of RPM you would need to pull off such a high HP per Liter figure. If we assumed you could pull off the same peak torque figure at a higher RPM, you'ld need to spin the motor to almost 9500 RPM to achieve 470 HP at the crank (what you would need for 400 WHP assuming 15% drivetrain losses). However, chances are, you'ld be making less torque where the peak HP occurs. If we assumed you could get about 230 lb-ft of torque then you would pull off 470 at the wheels at about 10,700 RPM. This is no easy feat considering the engine wasn't designed with the intent to rev that high. Such engines generally have short strokes to reduce piston speeds (which reduce tensile loads on the rods). Sure, you can try and destroke the motor, but then you'ld lose some displacement, which would likely lower the amount of potential torue available at any given RPM. This would require even higher RPM operation.

You could try and increase volumetric efficiency to increase the torque output enough such that it would reduce the need for such a large jump in engine speed, but you'll likely end up with an engine that is not streetable, needs regular rebuilding and idles at 3000 RPM. The old 240sx motors (KA24E) used in SCCA GT3 competition are putting out about 300 HP (from what I've heard) from 2.4 liters which is close to the HP/Liter figure you'ld need. But these engines idles at some 3K RPM, are rebuilt typically at the end of every season, have a narrow powerband and despite being old engines, would probably exceed the build budget you have for the 3.7L VQ. The VQ, with all its technology and complications will likley require a much bigger budget. Not to mention, the KA24E's development to the point it got to was spread out over a long period of time and at this point in time, the people building these motors are getting paid more for the work rather than the R&D.

To be honest, if you want a 480 HP car, I'd recommend buying one that way. Especially if you want to avoid turbos. And just to put things in perspective, Nissan's $70K GT-R uses turbo out of a similar sized motor to pull off a little more HP than you are trying to achieve. BMW is putting out about 400 HP from their 4.0L V8 and about 500 HP from their 5.0L motors in their M cars. Do you really think that some shop is going to be able to out do the engineers that designed these motors by that much for that cheap?

I'm not trying to berate you here. But your goals are quite unrealistic. With $10K split between the engine, suspension and transmission (not sure what kind of work you are planning to have done here), you might be lucky to get the factory crank HP rating at the wheels.

[Sentientbydesign]

Chano...If I build the data-link systems seen in the movie "The Matrix" would you be willing to let me download your brain? I'm sure I have plenty of empty space in mine and could use your knowledge base!

[C-Kwik]

Chano...If I build the data-link systems seen in the movie "The Matrix" would you be willing to let me download your brain? I'm sure I have plenty of empty space in mine and could use your knowledge base!

LOL. Only if I get to use it to learn Kung Fu.

[Fahad]

Great info. So for $10k I will be looking at 330 WHP?

and what should I expect in the 1/4 mile?

Thanks,

[C-Kwik]

Great info. So for $10k I will be looking at 330 WHP?

and what should I expect in the 1/4 mile?

Thanks,

Not what I said, I said you might be lucky to get that. Keeping in mind that 330 WHP is still 50 HP over stock at the wheels.

But your question is hard to answer as work done within the budget you speak is likely going to consist of bolt-ons. And chances are, if you added 5 parts that claims a 10 HP gain in HP, you'ld end up with something moe like a 20-30 HP gain total. Many bolt-on manufacturers will publish the peak gains in power. Not the gain in peak power. There is a huge difference as a 10 HP gain at 3000 RPM does not change the peak HP of the motor by 10 HP. The gain would have to occur at the RPM where peak HP occurs. Depending on the product, you could end up with a slight gain at peak Power. Adding a bunch of these types of products up generally won't push the peak as fast as the published gains might suggest.

This is not to say mods may not provide welcome gains. If significant gains could be realized even around the RPM at which peak power occurs, it is still providing more power where it counts. The right comination of parts, could result in very little change in peak HP, but have a much broader powerband. The "area under the curve" would be bigger and there would still be a nice gain in overall acceleration.

That said, there are also combinations of mods that can cause a sharp increase in power within a short range of RPM's. Many race cars are actually tuned this way and coupled with short gear spacing to maximize use of the short but high powerband. Few race cars need a big broad powerband, especially with a good driver behind the wheel as they will keep the engine operating within that range of RPM's. A small effect like this could be achieved, but it would likely reduce power elsewhere in the powerband, reducing its streetability. But putting something together that achieves either result effectively, especially this early in the life cycle of the motor, would likely be the result of chance. It would take quite a bit of trial and error and/or extensive calculations to effectively figure out the best combination of parts and part design.

Lastly, as far as 1/4 mile times, google 1/4 mile calculators. Try a few out. They simply require the weight of the vehicle and the HP output and will spit out an estimated 1/4 mile time. It's not going to be perfectly accurate as there are a great many variables to be considered, but without having a lot of relevant data, there is no way to accurately predict a car's rate of acceleration with a high degree of accuracy anyways. Frankly, the calculation would be rather complicated anyways and most would leave it to a computer to solve.

[tollboothwilley]

I think stock G37's have run around 13.7

So, maybe you could guess around low 13's. High 12's if its tuned properly. That would be a total guess but I think it could be possible depending on how you go about spending your $$

[Fahad]

Really appreciate the help.

I am looking to buy a fast RWD sedan manual trans under $50k, is there anything other than the G37?

[Sentientbydesign]

I think stock G37's have run around 13.7

So, maybe you could guess around low 13's. High 12's if its tuned properly. That would be a total guess but I think it could be possible depending on how you go about spending your $$

You really think he can drop a full second off the quarter mile with bolt ons and a tune?

Fahad,

Just go supercharger or turbo. Attaining your goals will be a lot simpler.

[Fahad]

I have never liked driving a car with aftermarket F/I.

I think I need to test drive a blown G37 to decide, so which shops do you recommend in Texas and Florida?

Thanks a lot,

[C-Kwik]

Really appreciate the help.

I am looking to buy a fast RWD sedan manual trans under $50k, is there anything other than the G37?

How fast? The G37 is pretty quick. But you can't expect exotic car-like performance without putting some money into it.

Frankly, I can't think of anything under $50K that will offer the kind of power you seem to be seeking without the use of turbos (factory turbos included) and in sedan form. If you could spare a bit more coin, the BMW M3 Sedan would get you in the mid 300 WHP range and provide exceptional handling to go with it. If you're willing to go with a turbo motor, a BMW 335i sedan could be had at about $40K MSRP ( i don't know what they are actually selling for though). As its a turbo motor, its likely easier to extract additional HP from. Simple piggyback computers have already put them close to M3 power levels (Vishnu claims some 70 WHP with their piggyback computer). Mods done to increase boost safely could probably exceed that (Disclaimer: This is merely a generalization made about turbo motors, not necessarily specific to the 335i).

[Fahad]

I am looking for 11's in the 1/4

I've been thinking about the M3, and found some brand new 2008 in the 50k's.

Never thought of the 335, it looks like a great choice for $40,000 and it's advertised to do 0-60 in 5 seconds flat

The Lexus IS-F sounds good too, but I don't think I will get a long with the 8 speed transmission.

Thank you very much guys for all the info, I will do some research on the BMW.