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@SLEEPER Nothing worth doing is without challenges 8^) An interesting tidbit about the HR12DDR, it uses variable expansion. This will add anothe level of complexity to this project but will also provide more options in tuning the engine. As per your comments about the max head flow, I'm sure...

@Dr. Acula I've tried looking up interviews with Abarth and Martini to hear what they did in the S4 but found little useful information. What source do you have that would help me? @SLEEPER As you correctly point out, the heads will be restrictive but I think I can overcome that with an...

Yes, a puny 77 cubic inch displacement. The ramp up at 3500 should be exhilirating and depending on the gearbox, it can happen right at 50kph in 4th and 85kph in 5th; exactly where you want it on the street.

Here is the planned torque output for S/C=5psi and adjacent T/C=36psi: RPM torque 1500 80ft-lbs 2500 95ft-lbs 3500 120ft-lbs 4500 200ft-lbs 5500 220ft-lbs 6500 220ft-lbs 7500 225ft-lbs 8500 225ft-lbs 9500 225ft-lbs 10500 216ft-lbs For those following along, plot...

Let’s look at one last real world example to nail it down for all reading: S/C = 8 psi T/C = 24 psi atmosphere = 14.7 psi adjacent feed calculation: (8+24+14.7-1.5)/14.7 = 3.0 pressure ratio and 44.1 psi @ 14.7 psi ambient inline feed calculation: (8+14.7-1.5)/14.7 x (24+14.7-1.5)/14.7 = 3.64...

Yes, the pressure ratio is multiplied inline and summed when adjacently (parallel/common) piped. In my instance, I lose 1.5psi through my air filter, manifold restriction, etc. Take those into account and your numbers match mine.

Here is a practical example of how this works: S/C boost =5psi T/C boost =32psi atmosphere=14.7psi inline calc: (boost+atmosphere-loss)/atmosphere = 54psi adjacent calc: (boost+atmosphere-loss)/atmosphere = 50psi inline pressure ratios (1.24x3) adjacent pressure ratios (5+32+14.7-1.5)/14.7

As I understand it, the parallel setup is additive (10psi +10psi), the sequential is geometric (1 bar into 1 bar yields 4 bar).

Thanks for the tips, it saved me some time. Stage intercooling has many benefits and the additional pipe itself is one of them, especially when the pipe is heatsinked and in the airflow. Additionally, the added via gives the pressurized air more time to settle and cool. Think about a shop...

Yes, the supercharger is the lead in, the turbo mixes in around 2500rpm but doesn't come full on until 6,000 and the S/C starts disengaging at ~5,000. The S/C alone peaks torque at 4400rpm with 105ft-lbs, falling off rapidly to 88ft-lbs at 5600rpm. The Audi 1.4L TDI inspired me to give this a...

I'm looking at hooking my G2.5-550 turbo on a tiny supercharged engine which makes 80-105 ft-lbs 1000-5500rpm by itself. I want my final result to be 433whp with torque not exceeding 250ft-lbs through the very wide power band. The supercharger pipes directly into the intake manifold so some...

Not an issue, it's diesel now so detonation is good :) More specifically, the engine has VVT and it'll be tuned to avoid an unburned fuel condition even at 2 bar.

A number two daily and weekend track toy is the plan. See my other thread here for more information.

@obi_waynne Yes I have, 100lb/hr with high atomization and wide pattern look like the solution for an 80% duty cycle but I might be able to get away with the ubiquitous 80lb'ers. The fuel pump will need to be stout too (60psi). I plotted a 2 bar boost map for a garden variety T3-60 fully...

For those of you who have been following my project here, you might be interested to know the change in tack that I'm taking. The idea is now to make a 400whp diesel from a stock 1.2L all aluminum 3. I've figured a map like this would suit the Nissan HR12Dxx with 25lbs dialed in. Power band...

The T5WC I'm planning on using has a 3.73 final gear. It's set up for overdrive to save fuel. First gear is pretty short so a puny torque down low shouldn't hurt me much. Its top is ~142mph@5800rpm with 225/50-16 rubber. If I use the same wheels and don't improve the aero, the top will be in the...

I need to apologize publicly to @TCJBOLDIE and eat the crow that comes along with that. Yes, when you bore a cylinder you increase the amount of air and if you don't proportionally address the heads, you are in fact pushing more air into the same vertical space so compression does increase...

It's not the same space when you increase the bore. The increased diameter increases the volume displaced. I don't know how I can state it any more plainly. If your race engine builder agrees with you I don't want his engines :)

Increasing the bore increases the volume of the cylinder for the same stroke so the CR is lowered. The "bowl crown" pistons are also increasing the cylinder volume for the same stroke and that also lowers the CR. @obi_wayne Yes, I considered that but don't know of any elegant way to disengage...

@obi_wayne The DIG-S has two versions, one with 12:1 and one with 13:1 compression but when you extend the bore to ~4", the compression drops to 9.5 on the 12:1 engine. I'm looking to push 40lbs of boost on the 3 cylinder.

I had hoped to end up with a DIG-T-R but failed so I'm looking at building one up from the DIG-S. What are the challenges I'm likely to run into?