Supercharging a gtr!

Guys, do u know of any madcap who had supercharged his/her GTR? What do u all think? Will that be super good? I mean, a supercharged GTR, wow...instant response along the whole power band (sacrificing a bit of top end, of course), ATESSA to ensure traction...wudn't it be excellent? Can it be done?

Don't know of anyone, but I suspect a lot of people are quite content with turbos on their GT-Rs. With proper tuning and turbo sizing, you can have pretty good response in addition to the better top end. You'll have your cake and eat it, too.

I think the biggest problem would be finding a S/C of the right size and design that would fit in and around the RB engine, and still allow intercooling so you could run enough boost to make similar useable power levels to a Turbo(s).

Your biggest problem is room. Even if you managed some how of mounting the sc on the turbo side of the motor there is very little room to add the pulley, unless you wanted to shift the radiator infront of the core support.

Ive seen such, there is a greddy model which visually appears to be a turbo but really is a supercharger, it was showcased at TAS, and If I remember right it was installed in a r33 in the show. I dont know how such equipments as a supercharger can be set up on a skyline but I guess the downsides are more concentric then the pros. For one I think a skyline should be pushed to the limit, how would someone be able to do that with a supercharger lol. If you plan to use one, get a toyota or scion lolz cause I think its not the place for a skyline really. Frankly, I see no point in it, yes boost would be ready all the time but that doesnt matter, best you be pushing is 500hp with one.

There's actually a mate of mine who just put a T78-34D turbo on his R33 GTR. The lag is more than he expected and has considered and talked to a company that does side mounted S/C kits for V8's about puttig on his GTR to get more responce down low and somehow venting after the turbo kicks in. It will be a tuning nightmare from hell, not to mention pluming it all in.

Ahh the wonders of Twin Charging!

I assume he will talk to the Panda about it?
He's done several Twin Charging kits for the 4agze in Levins and MR2s. I know hes done one with the HKS kit, and I think he's done one with a custom built kit.


Also have a look at this :http://geocities.com/MotorCity/Lane/1231/twincharging.html
Its a totaly custom build useing a Ford V6 turbo on a 4agze. Very clever install, although it dosnt seem to run as well as it could.

Ahh the wonders of Twin Charging!

I assume he will talk to the Panda about it?
He's done several Twin Charging kits for the 4agze in Levins and MR2s. I know hes done one with the HKS kit, and I think he's done one with a custom built kit.


Also have a look at this :http://geocities.com/MotorCity/Lane/1231/twincharging.html
Its a totaly custom build useing a Ford V6 turbo on a 4agze. Very clever install, although it dosnt seem to run as well as it could.


Actually no not Panda.

And as I've said a tuning nightmare!

And as I've said a tuning nightmare!


All you need is an ECU that will allow two differnt fuel and ignition curves to allow for the two very differnt Boost levels. It would simply switch curves at a preset boost level.

It's more than that actually. Having two different maps that can run sequentially isn't and hasn't been proven yet. Too many variables.

We are attempting to super-turbo my altezza right now, however, the crossover point is proving to be extremely difficult. I have a japanese tuner working on it, but i am about to give up and simply install the turbo kit.
There are a few EK9's I have seen with it, and they are a kick in the pants, but for the GTR to incorporate it, you would need to add a bump or raised portion on the bonnet to fit the mechanisim itself into the vehicle.

Madmattgtr who is member of this board had a vortech supercharger he is trying to fit on his gtr with the t88 single conversion:
http://www.automotiveforums.com/markh/gtr%20pics/

If it all goes as planned, it will be crazy fast. As of right now he is putting 520 ps to the wheels, and he is really hoping for a better ET, and not really any more HP. He is going through Bee Racing in Tokyo for his work, so it should be interesting in the end.

Matada, please correct me if I'm wrong...

The biggest drawback to adding the larger single tubos is the massive lag before spoolup. Matt's GTR is a perfect example of this. It doesn't even start to provide any boost until 4500 RPMs. Of course, once his engine got there... WOW!

One solution that I have seen in the past is a wet, 50 shot of NO2 that is wired in series with a rev-limitter switch and instead of a button, it's connected to an actuation circuit that turns the only sprays under WOT when the system has been armed. This way the NO2 cuts out before your boost levels climb and you can avoid damaging your motor.

If set up properly, it's a viable solution and much cheaper than a supercharger.

I was trying to recall the Auto Saloon pic that would go well with this discussion. I know I'd downloaded it, and found it today. Here it is, the setup I would love to have!

http://bryroz.users.btopenworld.com/SuperRB26.jpg

Having two different maps that can run sequentially isn't and hasn't been proven yet. Too many variables.

You mean it dosnt work for this aplication, or it can't be done?
Becuase it has been done, its how Honda got VTEC to work, two seprate maps that overlap as the cams change lift and duration (same effect as switching boost levels, just a little milder).
Prehaps your mate could try giving Hondata a call, and see if they can tweak a V6 Honda ECU? (thier orginaly a Kiwi company so they might be interested).



Thats an awsome pic GTES-t I wonder though if they all spool at about the same time, since I see no one way valve, if the S/C was shut off, or provided less boost than the turbos there would be a vacum somewhere on the boost side, as they S/C tried to blow boost into the turbos outlet, or vice versa.

matada by EK9, I assume your refering to Civics? They work well for the reasons above, you can run the s/c on the low lift cam lobes map, and the turbo on the high lift map. Basicly the engine and ECU etc is designed for two differnt power bands.
What model altezza do you have? We get 6cyl ones sold new here, but there are many imported 4cyl ones running around with the 3sge in them. Although its a very high strung version, with I believe VVTi-L. This should use a set up similar to Honda, and run two maps, one for low lift, and one for high lift.

I was trying to recall the Auto Saloon pic that would go well with this discussion. I know I'd downloaded it, and found it today. Here it is, the setup I would love to have!

http://bryroz.users.btopenworld.com/SuperRB26.jpg
Alas, you found it, thats the one I was talking about. :smile: :biggrin: :loser:

I have seen that pic for the last year or so, never in a car, and never any pics of it performance numbers. Does anyone know if this engine has ran?

moppie,

VTEC and a super-turbo combo would be a lot different, don't you think?

You can run a small supercharger, then block off that air, and then let the turbo kick up fore the higher revs, but like what was mentioned before, you just better off hitting it with a good 100 shot and use a window switch to cut it of as soon as the turbo is spooled.

The problem people seem to have with running an S/C and a turbo on the same engine is getting the fuel and ignition maps to work with the two differnt conditions each create.
If it were possible to have the s/c run up to say exactly 10psi and then switch of and the turbo come on at exactly 10psi then keep building boost it would not be a problem. But such a transition would be very difficult to arrange, would create problems at situations of less than WOT, and would limit the size of the turbo you could use, makeing the whole set up worthless, as you could achive a similar power band with just an S/C, or just a Turbo.

Instead in all the aplications discussed a large Turbo with a lot of lag is being used, with the intention of using an S/C to run the enigne up to a speed the turbo will produce boost, or even use the S/C to blow through the Turbo to spool it up earlier, minmising lag and greatly increasing the lower power band.
The problem is the Turbos are set up to run signifcantly more boost than the S/C will, and so some form of bypass and or shut off is need for the S/C to prevent it from over heating, and to ensure the Turbo gets the air it needs.
This creates a large spike in the boost levels over a very narrow RPM band as the Turbo comes on boost, which is something most ECUs seem to have a problem dealing with, and the easiest way to solve it seems to be to run two sets of ECU maps. One for when the engine is under S/C boost, and one for when the engine is under Turbo boost.
Im pretty sure you already understand that, but I felt the need to spell it out in order to make the comparison.

A VTEC engine or NEO VVTL, VVTi-L etc etc encounters the same problem when it switchs from the low rpm cam lobes to the high rpm cam lobes. In the space of 1-200rpm there is a very sudden increase in the amount of fuel needed, and a change in the ignition map. The mechanical means of building such a system have been around since the camshaft was invented, but the means of supplying it with fuel and altering the ignition map were not. Honda solved the problem by developing an ECU that was capable of running two sets of maps, and was able to switch between them depending on engine load etc. Both maps over lap, over a period of about 500-1000rpm depending on the ECU model. In the more advanced versions of VTEC (normaly on the Twin Cam engines) there is a period of about 400rpm where it can run on either set of cam lobes and either map depending on engine load, throttle position etc (stops it switching mid corner, or lets you run efficantly at above the legal limit).

This sounds to me like exactly what is needed to over come the change in fuel and ignition timing required to run a large Turbo and low speed S/C on the same engine.
Instead of a Cam Lobe cross over point, you would have a clutch disengage the S/C and a oneway valve open to allow air into the Turbo and close off the S/C, the ECU would simply switch over to its second set of maps over the same period this occurs. You could have one cross over point for raising RPM, and one for falling RPM to allow the S/C a half a second to come back up to boost, and the overlap on the maps would keep the engine happy with fuel and spark.

Judging from the the posts here, not all of which my over-used brain could process, decipher and understand, I would conclude that it's damn difficult to supercharge a RB26. :smile: OK, I will stick to the snails then.
But hell, the pic of the super-turboed RB26 is a sight to behold. This forum just rawk man...it's full of knowledge. :smokin:

Look at that drive pulley for that roots, its almost a one for one off of crank pulley, so what does that tell me, that engine is just for show. It wont work. Plus with that small belt, it will slip, it needs a much bigger cog. With my supercharger, my crank pulley is 8", while my compressor pulley is about 2 1/2" to give you an idea. And that is for only 12lbs of boost.

There are plenty of was to bypass the air from the super if you wanted to try to make thos set up work, but in the end a goos N2O shot will do the same thing :naughty:

it's not difficult at all.
consider how many domestics run centrifugal chargers that make just as much/more power as turbo cars.

you lose a ton of heat by ditching the turbos for a custom manifold, you slap on a big centrifugal (vortech, paxton, etc.)
not much different than a turbo.