TitaniumTT's I hope I make it to DGRR '09 Build

NoDOHC · 10-14-2009, 11:04 PM

I don't know how you made any boost at all with the charge relief vale open

361 WHp is even more impressive considering that.

If you can make 15 psi, than 400 WHp should be pretty easy.

Not only do you get the fast spooling of the twins, you get good power too (perfect for autoXing).

You have no idea how much you are tempting me to throw a set of BNR twins on my engine instead of the GT37.

The reason that I was curious about the NA power is this:
361 WHp @ 6700 rpm = 283 W lb-ft of torque.
283 Wlb-ft * 14.8/(11.5+14.8) = 159 Wlb-ft of torque (which is identical to what my engine makes at 6700 rpm). This indicates to me that either your engine flows a lot better than mine (which is very possible, as you have the 3rd gen intake and I have a 2nd gen intake) or I can use very simple math to compute the power increase by adding a turbo (power ratio = intake pressure ratio).

The properties of torque at a given air fuel ratio are basically fixed for the fuel type, compression ratio, combustion chamber design and intake port timing (exhaust port timing does not matter for peak power AFR). Since you have identical characteristics in all except for port timing (which is not significantly different) and maybe the compression ratio (I think you have 9.0:1, where my 8.5:1 rotors are machined down to 8.2:1 - but it has a small effect anyway). I would expect our engines to perform similarly for torque vs AFR.

That is why I thought it was awesome that you were running 13.0:1 AFR (which is about where I found peak power NA) so I can compare. I made 10 lb-ft (6%) less torque at 12.3:1 as I did at 13.0:1. I made a LOT less torque at 11:1 (like 20% less). I intentionally dynoed my engine NA so that I could compare the power numbers with and without a turbo (The goal being to make 2X NA power (430 WHp) at 14.5 psi boost).

It almost seems like you are doing a little bit of the development for me (and you are giving me hope that it can be done).

Keep up the good work!!

edit: The above was meant for both Brian and Dave, as I have no intention of discounting or ignoring the critical part Dave is playing here, 361 WHp and drove it home because the tuner knew when to quit.

10-14-2009, 11:04 PM	#11
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	I don't know how you made any boost at all with the charge relief vale open 361 WHp is even more impressive considering that. If you can make 15 psi, than 400 WHp should be pretty easy. Not only do you get the fast spooling of the twins, you get good power too (perfect for autoXing). You have no idea how much you are tempting me to throw a set of BNR twins on my engine instead of the GT37. The reason that I was curious about the NA power is this: 361 WHp @ 6700 rpm = 283 W lb-ft of torque. 283 Wlb-ft * 14.8/(11.5+14.8) = 159 Wlb-ft of torque (which is identical to what my engine makes at 6700 rpm). This indicates to me that either your engine flows a lot better than mine (which is very possible, as you have the 3rd gen intake and I have a 2nd gen intake) or I can use very simple math to compute the power increase by adding a turbo (power ratio = intake pressure ratio). The properties of torque at a given air fuel ratio are basically fixed for the fuel type, compression ratio, combustion chamber design and intake port timing (exhaust port timing does not matter for peak power AFR). Since you have identical characteristics in all except for port timing (which is not significantly different) and maybe the compression ratio (I think you have 9.0:1, where my 8.5:1 rotors are machined down to 8.2:1 - but it has a small effect anyway). I would expect our engines to perform similarly for torque vs AFR. That is why I thought it was awesome that you were running 13.0:1 AFR (which is about where I found peak power NA) so I can compare. I made 10 lb-ft (6%) less torque at 12.3:1 as I did at 13.0:1. I made a LOT less torque at 11:1 (like 20% less). I intentionally dynoed my engine NA so that I could compare the power numbers with and without a turbo (The goal being to make 2X NA power (430 WHp) at 14.5 psi boost). It almost seems like you are doing a little bit of the development for me (and you are giving me hope that it can be done). Keep up the good work!! edit: The above was meant for both Brian and Dave, as I have no intention of discounting or ignoring the critical part Dave is playing here, 361 WHp and drove it home because the tuner knew when to quit. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic) Last edited by NoDOHC; 10-14-2009 at 11:08 PM.