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I was inspired by this thread and was hoping to continue that topic with what the ten years since have taught us. The DIG-T-R took a stock  3 cylinder Nissan block and got 283ft-lbs out of it with just a turbo. Those engines are plentiful in junkyards with superchargers already on them so what would it be like to add a turbo  to give it the top end it's badly missing? The engine is smooth enough to run to 10K so 400whp seems possible to me in a twin charge scenario, any thoughts?

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In the last 10 years what I'd say is that turbos have become infinitely better as well as the ECUs and boost control methods. 

The days of a big turbo being an on/off switch power delivery are dead and buried... And so are the majority of benefits of twin charging outside of gimmick factor TBH

Turbo + nitrous activation for spool has all of the benefits with none of the downsides (apart from cost of nitrous and blowing yourself up, but meh)

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@Roman

For pure racing applications I agree with you. There's no need for the added weight and complexity of twin charging but a street car/weekend oval  racer is a different story. A tiny engine like the HR12DDR that could make >400whp, be usable in traffic AND be a retrofit in just about anything would make it competitve with anything on the market. Imagine this engine in a classic Miata or an MR2!

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@00quattro00

You could compound trubo but why would you have to if the S/C is boosting the bottom? How much intake aperture do you need to get 400whp worth of air into the cylinder with a net PR of 2.8? 3.0? 3.2? The DIG-T-R had a different head than the stock HR12DDR but the same physics apply. I suspect the stock head is up to the task but the calculations asked for on the aperture will firm up my suspicions 8^)

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Twin charged is lush. You could run it compound with the turbo feeding into the super and both running, or for better efficiency you can run sequential and bypass the super when the turbo kicks in, but that's a bit more complicated, especially to get a smooth transition.

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Are you wanting  to get 10,000rpm and 400hp from a standard engine? 
The only reason this motor can work at 12:1 compression with a supercharger is because its a miller cycle engine.
high comp and miller cycle are both roadblocks to big power.
10k rpm is ambitious as well



 

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You could just run a single turbo and make 400hp and still have an easily driveable engine. A mate races a yamaha yxz1000. They have a na 1000cc 3cyl. It has an efr6258 on it and makes 300hp easily on a completely standard engine, they are not allowed to change any internal components so is limited by that but it could easily be over 400hp.

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@Roman

The engine block has micro polished cylinders and should rev nicely. The DIG-T-R ran it at 7500 in an endurance application. In my opinion, this engine will rev to 11k smoothly.

 

@Yowzer

Using a "normal" cam makes 93 pump gas an improbability given the outcome I desire. Remember, this is for a do anything engine, I don't want to sacrifice the good engineering on the low end just to make peak power. There may be a way to use the variable expansion even in the turbo band as a knock or low octane control  or possibly a low load cruise mode. As long as they don't get in the way, options are usually a good thing. I may up needing a custom cam anyway if the stock valve apertures are a problem but having two or more profiles to work with is not a bad thing.

 

@00quattro00

I don't consider 40 ft-lbs of torque drivable on cars that may approach 3000lbs. That may be fine on a Miata but not on a salon/sedan. The engine needs help down low. The S/C works adequately for that and you're not paying for it. What's not to like?

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What are you trying to achieve by using an engine like that in a heavy car?

 

Most modern engines have a small bore and long stroke as it is better for emissions and will likely have unfavorable bore/stroke/rod length to be spinning them to 10k

 

Do you know what this engine weighs?

 

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attempting to get big torque numbers on a small engine at low rpm.  pump gas wont be your friend.  and the engine also wont be your friend.   you'll be running big cylinder pressure which is hard on everything.   not saying your idea isn't possible, but will never have big amounts of torque right off the bottom.       

 

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5 minutes ago, kpr said:

attempting to get big torque numbers on a small engine at low rpm.  pump gas wont be your friend.  and the engine also wont be your friend.   you'll be running big cylinder pressure which is hard on everything.   not saying your idea isn't possible, but will never have big amounts of torque right off the bottom.       

 

Isn't that how the TSI engines work?  1 litre triple with 170Nm of torque from 2000-3500rpm or 2 litre with 320Nm from 1500-4500rpm.

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8 minutes ago, locost_bryan said:

Isn't that how the TSI engines work?  1 litre triple with 170Nm of torque from 2000-3500rpm or 2 litre with 320Nm from 1500-4500rpm.

Vw made a 1.4l twin charged engine and then went back to a single turbo on the new version for better efficiency. The later ea211 is a 1.4l 4cyl that weighs 104kg complete and makes diesel like torque with 250nm @ 1500rpm

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Just now, 00quattro00 said:

Vw made a 1.4l twin charged engine and then went back to a single turbo on the new version for better efficiency. The later ea211 is a 1.4l 4cyl that weighs 104kg complete and makes diesel like torque with 250nm @ 1500rpm

That and they were just absolute fucking dogs - Of all the Mk2 Fabia RS in the UK, there's less than 10% still rolling around with the engine they left the factory with, and a substantial majority on their 3rd or 4th engine.

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1 minute ago, Alfashark said:

That and they were just absolute fucking dogs - Of all the Mk2 Fabia RS in the UK, there's less than 10% still rolling around with the engine they left the factory with, and a substantial majority on their 3rd or 4th engine.

Can remap them to stop them stuffing pistons or run them on gull 98 with the ethanol, I know of one where thats all the owner has used from new and is upto 250km with no major problems

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Just now, 00quattro00 said:

Can remap them to stop them stuffing pistons or run them on gull 98 with the ethanol, I know of one where thats all the owner has used from new and is upto 250km with no major problems

No doubt, but there's issues with the metal in the components too.  I wouldn't willingly own a hand grenade like that, but hopefully he avoids any issues.

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