Hi All,
We're designing a sports car (pics attached) and planning to use 20B in it.

I'm not talking high volumes but even 10-20 per year eliminates used core option. Engine has to be build from new parts.

Obviously we will come to some reputable builder ordering the engines (most likely Rohan but Cam from Pettit and Kiwi-RE is also a possibility) but I'm trying to build my own understanding of what makes the best possible package.

Goals are:

1. Extremely reliable, user friendly i.e. streetable engine. This means good stable idle, linear power/tq build up. Emissions and noise level is also important.
2. I want two boost levels implemented (on the switch) - one good for ~ 450rwhp and another for 650-700 +???
This and noise considerations doesn't allow me to use twin screw S/C so turbo seems the only way.
3. As light as possible.

After reading through 16 pages of this extremely informative forum this is my thoughts.

1. Weight - eliminating some standard parts might help: things like water pump, factory intake - we will make our own C/F intake with integrated laminova intercooler.
Racing beat have some great alu plates but they don't have full set. Rohan designed and testing (according to some posts, but I didn't talk to him about this) his own alu "fat" plate. I actually feel vague here and don't have clear picture of what is available. It seems that atm there's no "full set" available. Can anybody help with some info?

2. Reliability... Dry sump as this is track oriented car with up to 2G cornering capasity. Also more oil adds weight but also helps cooling it. Oil/water heat exchanger - we had best results on our road racing cars with this setup. Cooling... 3" two raw racing radiator with carefully managed air flow to and out of it.
Rohan's Stud kit and e-shaft. NRS one piece 3mm apex seals. What sort of surface/material treatment is recomended for rotors, housings etc? What it will give?
Obviously suitable fuel system with surge tank.
What oil and cooling mods are recommended?
What also should I consider?

3. Power... I want fastest possible spool. Please give me your recomendations here - with details if possible. Many people are talking about triple turbo's. GT2871 where mentioned - what is advantage? Many people use single GT42's, some use twin (non sequential) GT30's... I'd like to know your opinions. Also what is the weight of GT42? What is GT28's weight? Tripple turbo manifold will also add a little weight.

I outlined my power (and other) goals above ... but may be it's not possible to have it all?

4. Sourcing the parts... Kiwi - RE is a possibility. They don't have "fat" plate. This is great for PP engines and it also makes for shorter and lighter engine. I've read that some people use it as side ported engines but question is will it allow for my power goals?

Cost... I'm not trying to make cheapest 20B. I have straight goals but I want to spend money in most efficient way without compromising final product.

I'd love to hear your suggestions/opinions.

Thank You
Ted

 

I know there are tons of experience and knowledge on this forum.... Please share!

Thank You
Ted

 

What's your weight target for the vehicle? 650-700rwhp is an extreme amount for a front engine rear rear drive combination (especialy if the finaly weight is sub 3,000lbs). Would be really hard to put the power down at that level.

The side ports will easily hit both your hp goals. That being the case your better off sourcing regular used 20b's. Dowel pinning will add some reliability to the block. The side ports also give you your best chance at having decent emissions.

By the way that's a really nice looking car. Hope you get the info your looking for.

 

If by side port u mean mean P port

i've read that peripheral port motors make the most power..

but their idle/streetability sucks... and they're engine life span is short... power band is very high up and u have to rev to the moon... more suited for a track car then a DD

 

No, side port refers to the stock intake port location.

 

Riccardo makes rear transaxles for front engine cars. I believe they also made the gearbox for the 599 GTB. Although it's probably an expensive course of option.

http://www.ricardo.com/engineeringse...?page=products

If it were me personally, and I had the funds. I would build the 4 rotor kiwi RE offers (23A) instead of a turbo 20B. I think it would "sound" better too, but that is merely an opinion.

 

If you had the money, I would get a translator or take a trip to Japan and talk straight with Amemiya himself. He puts out some of the best looking best performing rotaries in the market, not just a lightweight car used for drag racing like a lot of builders. I'm sure he would be reliability oriented too.

As for the sound/noise aspect, you would probably want to go turbo because an NA makes a shitload of noise if you want power out of it. And I don't see an NA making that much power at the flip of a switch.

Probably MoTec engine Mgmt.

Ceramic coated housings maybe by JHBperformance, if they could ever get thier **** together.

NRS Seals definitely.


Probably a large streetport because a bridge doesn't offer great idle quality or so I've heard.

If it were me it would be a TT 20b, To my understanding the sequential turbos of t he FD made a great powerband from low rpms.

Maybe a smaller and larger turbo orientation.

With a good port on a 20b I don't think spool up would be a problem with 2 medium sized master power turbos.

Those are just ideas and theres a shitload more knowledgeable people to talk to than me. Maybe give RX-7 Specialties out of canada a call. They do 20b's a lot.

 

That looks....very TVRish

 

If your seriously willing to have someone make the engine for you form new parts why not redesign the damn thing ground up and make it a 2 or 2.2L 4 rotary engine? with smaller lighter rotors, 2 or 3 piece eccentric shaft. Side ports, with 13b exhaust ports, ITBs...and Direct injection? I bet you if you could pull this off you would def have one of the most insanely disgusting blocks in the world? And then use 2 gt35rs, or maybe even 2 42rs with 1.06 ars or bigger, with a medium sized exhaust manifold for proper power band gains, and the possibility of revving right up to 9000 rpm. Redeisng the cooling channels in the block to car a bit more fluid and use an electric water pump! While your at it go and Integrate the Supra getrag tranny? That thing is unstoppable and the gearing for it would be pretty damn good too, though I would probably put in a slightly taller final gear to let the car hit 200-215mph at the top of 6th gear. I mean correct me if I am wrong but you seem like a very knowledgeable CAD user. And it seems as though you could have some of this stuff CNCed for you. And look at your design my guess like the other guys is that you might be one of the laid off TVR guys haha. If you are I am sorry. But last I looked they weren’t engineered in ST. Petersburg. They were simply owned by a damn Russian for a while. (BTW, I’m Russian as well)

 

I think a mildly ported 20b w/ itb's and good sized twins or a supercharger? would offer all of the things you want.

Mild porting will give you a linear power band with more potential on the top end.
Itb's for throttle response

a supercharger would be good for maintaining a more streetable car. twins would better for reaching the higher hp ranges.

Studs/pins and nrs seals solve your reliability requirement.

I don't suppose you have a higher resolution picture of that car? I'd like to use it as desktop background

 

I wouldn't go itb's if you want it to be user friendly

I had itbs on my 20B, yes it made a massive difference to power na but with a turbo you won't need to go there, the stock manifold has been proven to make big power turbo.

The itbs make light throttle driving and especially take off difficult for someone who is not used to them. It doesn't take long to get used to them, but everyone who drove my car with them on bunny hopped down the road, the throttle becomes very sensitive.