supercharged sr20det

[AndrewD]

has anyone here either seen a gtir or the sr20det (yes still with a turbo) that has been supercharged?

interested to see how it would pull,

i can see that if, and thats a big IF, there is enough room,
1. you could run a bigger turbo (much bigger)
2. supercharger will pull down low, turbo up higher

anyone seen or even better have pics????

 

[Allan GTI-R]

it's been done to at least 2 SR20DE's here in Sydney.

I can tell you now - they suck big time, they're so slow it isn't funny.

it's a bad idea only thought about on forums, don't try it !

 

[AJ4]

Hey ! I'm building ( the first ? ) supercharged SR20DET in the UK, and it makes full boost ( 29 Psi ) from 2500 rpm and has flat torque curve up to 6500 rpm. Don't tell me thats slow....

( no turbo btw, just a blower )

 

[J-GTi-R]

That would be an SR20DES then...

I have been reading about a new type of supercharger that is being used, kind of looks like a turbo, but has a gearbox on it to step up the boost as the revs rise. Gets past the old supercharger problem of either not developing enough boost for serious power, or developing enough boost for the power, but then seriously over-boosting at low revs and making the car run like crap.

I did wonder how it would owrk on an 'R.

 

[AJ4]

I would have had a SR24DES if JWT would get their finger out their ass and sell me a stoker kit :roll:

Am using a Whipple twin screw, positive displacement type. The idea is it makes full boost low down and drops off as the revs rise, so the torque curve is almost perfectly flat over a very wide range. I don't give a shit if the engine only makes 300 bhp, if it makes it from 2500 rpm to 6500 rpm with zero lag

 

[Sirnixalot]

the whipple is the best design...its a screw type positive displacment...not to be confused with the roots style positive displacment.

I dont think its a "waste" per say but you would get a faster car with 1/2 what it costs you to smack a larger turbo on it. But i understand that individuality and creativity come into play and not every one wants to follow the tried and true path.

I still think its a better idea than a twin turbo gtir. That being said twincharging a GTi-R is even more worthless than a twin turbo GTi-R.

Using a centrifugal blower will not gain much as it creates boost exponentially. If you have 4psi @ 2000rpm you will have 8psi @ 4000rpm.

A positive displacment will create boost from idle but it will fall off in the higher rpms because it is limited flow wise. The Whipple screw type doesnt suffer this problem as much as the Eaton roots type.

If you ran a positive displacment in series with a large turbo you would would...ill finsih this later...gotta do some work

 

[kyepan]

this/last months bansai magazine has one of those new superchargers with a gearbox being fitted to a honda civic, check it out.

 

[Fast Guy]

Hey ! I'm building ( the first ? ) supercharged SR20DET in the UK, and it makes full boost ( 29 Psi ) from 2500 rpm and has flat torque curve up to 6500 rpm. Don't tell me thats slow....

( no turbo btw, just a blower )

So how long til it's complete? and what sort of cost are you looking at?
It's something I've thought of doing one day and might just if your results are good.

 

[AJ4]

I disagree with Sirnix a little bit about the cost. The supercharger is less than a grand, which is very comparable to a big turbo. I also don't have the problem of trying to fit a big turbo in, it goes where the air con pump use to be. I don't have to worry about a custom made 4 branch manifold, I can use a standard 4-2-1 exhaust. The supercharger doesn't need any water or oil lines so is much easier to install. I don't need a dump valve anymore ( ) I can ditch my front mount and go back to top mount again as the exit charge is heated nowhere near what a turbo is. I wont have any lag like I would with a big turbo, hence I wouldn't need to consider nitrous as an antilag system.

At the end of the day, its an individuality thing like he says. I don't care if its not the fastest Pulsar on the planet, I know it will still be a bit nippy

At the moment I've been holding out for a JWT 2.4 kit, as I want the extra displacement for maximum low end torque and can't rev too high with the charger anyway. This is not looking likely though, so I'm going to stick with my tomei 2.2. I've got a spare engine coming in a few weeks ( although I have been messed around a bit ) so I can start building it up then. Am hoping to be finished by the end of the summer, its taking ages to get bits

 

[Sirnixalot]

the cost of the bracket fabrication, plenum adapters from the supercharger as well as the intercooler setup.

you wont be able to fit it where the aircon pump is as it will hitn the headers.

if you mount it above the headers and relocate the alternator lower down that would be your best bet.

You will NEVER be able to run 29psi UNINTERCOOLED. Also you still need a dump valve...just cause you change the type of compression doesnt mean youve changed the forces on the blower or engine. It might cause some belt slippage.

take a look at www.jacksonracing.com and peep their Mazda miata kit....if you can get a similar config and use a water to air intercooler mounted where the batter is that would be best

 

[AJ4]

Sorry, I never said I wasn't going to be intercooled, I said I'd go back to the top mount again, maybe try and find one a bit more efficient if needed. I've already got WI which is a great help. The charger is quite small so will fit where the aircon pump used to be. Its a bit close to the exhaust, but nothing a small heat sheild can't fix. Good suggestion about mounting it above the alternator, never really considered that until now... ( just when I thought I had it all planned, lol ). I thought about mounting it dead on top of the block, inside the cheesgrater but I couldn't get a clear line to any of the pulleys without riggin up some elaborate slaves.

I never really considered an air/water intercooler but its definately a good idea 8) I won't be running anywhere near 2 bar to begin with, I was just pointing out that its possible to get the same boost from a charger as from a turbo. I know that bang for buck, a supercharger will always lose out to a reasonable turbo for all out power, but I'm just interested in the no lag/ power at idle throttle response. Most of my racing, sorry ahem, driving is in places where you can't spend ages screaming at 5000 rpm to keep the boost up I can't see the point of having a car that makes peak torque at 5000rpm and peak bhp at 7000 rpm when I very rarely get to rev it that high in normal situations ( ie driving to work on my private airfield )

I suppose there are arguments for and against dump valves, in any situation. Some people say they get better performance having positive pressure in the intake manifold before the throttle opens and the damage that is allegedly cause by stalling the turbine is not very common. Horses for courses I suppose, I've heard good arguments for both and wouldn't like to comment on which is better.

Thanks for the link btw, this is a bit of a prototype so any ideas I can glean from anywhere else is very welcome 8)

 

[Sirnixalot]

i like brain storming like this...and my last truck i was gathering some eaton bits to boost it as well...so i know a little of what it takes to fab up a kit for a motor that doesnt have any provisions for one.

To be honest if you could i would say the best bet would be to do a setup like the USDM Ford SVT Lightning or SVT Cobra R.

The supercharger is intergrated into an intake manifold which has a water to air core directly after the blowers outlet.

This would make a few things have to be removed or severly relocated on the R of course and it might not clear at all. But all the proper support brackets and what not are already inplace. And im sure you could modify the power steering pump bracket to fit the nose of the blower. This would eliminate an extra tensioner pulley. On second thought the whole blower couldnt move as its attached to the intake manifold. So an idler pulley would still be required. The intake for the blower is on its ass and that would be pointing toward the passenger side so all you need is a throttle body....i would use the SR16VE N1 tb its 70mm or something stupidly large (www.splparts.com can get them).

Couple that with a good heat exchanger where the old AC condenser was and youve got stealth. The water resivuar for the water to air setup can either go where the battery was, you can use the windsheild washer fluid resivuar or put one in the boot. I would get a higher flow pump if you put it in the boot.

Power steering....forget it

 

[AJ4]

I did think about mounting it straight on the inlet manifold, but I would have to drastically shorten the runners ( would rather keep them the same length ) and there isn't room for it unless I put another hump in the bonnet ( it would look like the loch ness monster ). It might also mean going to single point injection and I'd rather keep all the advantages of multi-point.

I've seen the inlet coolers you mentioned, or something similar on big hemi's where the blower sits on top with a ram intake and the cooler is sandwiched between the blower and the top of the head, looks like a good idea.

The biggest problem I have is finding a pulley, as you know if you look down the left hand side of the engine all you can see are pipes and engine mounts everywhere and not a clear pulley in sight The other problem with that is mounting a double pulley on any of the existing ones as I'd need to carve out a hole in the inner wing so it wouldn't foul on hard corners.

The reason I'm trying to get it in place of the aircon pump is twofold, one is that it is easy to use the original belt for the aircon, its inline and I dont have to worry about fabricating a double pulley. The second is that if I mount it with the intake facing the passenger wing, and the outlet facing the front of the car, I can use a very short pipe run straight up to the top mount. I've got a Forge at the mo, but its probably not necessary with lower intake temps, a top mount should be more than enough. The only problem I might have is the inlet pipe crossing the exhaust manifold, but if I get the ECU I want I can use a MAP sensor and just put the airfilter right on the front of the car next to the blower where it should pick up loads of nice rammed air.

I like your idea of putting the blower above the alternator, with a MAP I could then move the airfilter to right in the middle of the cheesegrater....

 

[Sirnixalot]

im sure you could keep the multi port fuel injection. basically sit the blower as close to the back of the block as possible, and have the air exiting do a 180* turn. Have the exit port on the blower point toward the firewall and make a plenum to join 4 1.75" runners to the head. Pretty much destro the quad throttls for the flange and injector bosses, weld the runners to the flange and voila (you could get some injnector bosses/bungs and make a flange).


tight compact package and unless anyone knew what they were looking at it would look very stock. The plenum seems large enough to fit a decent core in it.

sorry.,..im stuck on that design but your one seems quite possible as well. I would keep the front mount though.

 

[AJ4]

AAAAaaaaggghhh !!!! Stop giving me ideas !!! lol

What your suggesting sounds quite interesting, i'll have to go and have a measure up and see how it looks, I'd like to keep the quad throttles, much better performance than a single, but a single would be much easier to make...

Any other ideas or suggestions, feel free, nothings set in stone yet.

Btw, sorry for totally hijacking the thread

 

[Sirnixalot]

now that i tihnk more you could keep the IDTB's. just cut the flange off the upper half of the intake manifold...the one that connects directly to the fire wall side of the throttle bodies...just weld the pipes on to that flange and have it bolt directly to the throttle bodies like stock.

all you would need ot do is route the intake for it...thats just a bit of pipe 300zx maf and filter away....or if you get the MAP sensor...just a bit of pipe and filter away

 

[AJ4]

Yeah, I'd rather keep the individual throttle bodies, thats what make the engine so good in the first place.

I can't imagine how to do the belt though, I dont have my motor with me this week so I cant go have a look. I think I did consider where you said but decided it was too dificult trying to pick up a belt from the steering pulley, too many hoses and brackets in the way.

I take it you'd recommend removing the power steering pump and using that pulley ? Or put a double pulley on it ?

 

[Sirnixalot]

power steering...who needs it :lol:

 

[Fast Guy]

power steering...who needs it :lol:

Errrrr.......I think we do.

 

[AJ4]

yeah, I'm an 8 stone weakling trapped inside a 12 stone body, my golf doesn't have power steering and its a killer to park