3076 Surge Slotted Compressor Housing

[MrTerry]

Hey, i had a search and found a few bits of discussion but not really a straight answer.

Looking at the 3076 kit from gcg HERE.

There is an option for a regular 2.75 inch inlet or the surge slotted 4 inch inlet.

Im having trouble working out the differences between the two (aside from people liking the sound of the surge slotted ).

I figured the 2.75 inch would be less hassle cause i could stretch the standard intake pipe over it to drive to a shop to get a metal intake pipe made up (or would the standard intake with a metal insert work?), not sure how id get anywhere to do that with a 4, i guess id have to organise an intake pipe beforehand? ive never welded anything

Thanks in advance!

[Harey]

Hey, i had a search and found a few bits of discussion but not really a straight answer.

Looking at the 3076 kit from gcg HERE.

There is an option for a regular 2.75 inch inlet or the surge slotted 4 inch inlet.

Im having trouble working out the differences between the two (aside from people liking the sound of the surge slotted ).

I figured the 2.75 inch would be less hassle cause i could stretch the standard intake pipe over it to drive to a shop to get a metal intake pipe made up (or would the standard intake with a metal insert work?), not sure how id get anywhere to do that with a 4, i guess id have to organise an intake pipe beforehand? ive never welded anything

Thanks in advance!

First decision is will you be running the afm in the intake? If you are it makes the 4" a bit of an overkill if you are going to reduce it down to 3" for the afm anyway. The main advantage of a surge slotted compressor housing is that it will resist compressor surge.

All you would need temporarily is a 45 degree bend with a 4" -> 3" reducer to drive it down to the shop to get one made up.

Have a serious think about the afm location because if you can move it to the cooler piping you can then run a big 4" intake. I am guessing from your turbo choice your not too worried about stock appearance anyway.

[MrTerry]

First decision is will you be running the afm in the intake? If you are it makes the 4" a bit of an overkill if you are going to reduce it down to 3" for the afm anyway. The main advantage of a surge slotted compressor housing is that it will resist compressor surge.

All you would need temporarily is a 45 degree bend with a 4" -> 3" reducer to drive it down to the shop to get one made up.

Have a serious think about the afm location because if you can move it to the cooler piping you can then run a big 4" intake. I am guessing from your turbo choice your not too worried about stock appearance anyway.

Thanks jeff, im trying to keep it as standard looking as i can manage with a 3076 i guess the 2.75 would probably be the best way to go, seems like a hell of a lot less screwing around, just dont want to make a choice ill regret later down the track.

[Harey]

Thanks jeff, im trying to keep it as standard looking as i can manage with a 3076 i guess the 2.75 would probably be the best way to go, seems like a hell of a lot less screwing around, just dont want to make a choice ill regret later down the track.

You could just get a 4" -> 3" reducer straight off the turbo then a 3" metal intake pipe to the afm. Just do it all in black.

Not sure about squeezing the stock intake pipe over the 2.75" inlet. I think the general rule is try to ensure that nothing in your intake is smaller than the turbo inlet if possible. Reducing from 2.75" to 2.5" might be a bit of a restriction.

Here are a few of my lessons:

- First thing do not buy an autobarn88 intake pipe for your R34 GTT as it does not fit with an afm, I had to return mine.

- Make sure your blow off valve does return to the intake. I tried blocking my bov off and also using a 1 way valve but Trent reckons the R34 ecu is too smart and is hard to tune around. Even after it was tuned around I still had some popping with gear changes etc. So ensure this is plumbed back to the intake if you do go the custom intake route. I reverted back to the standard intake but I only have a 2.5" inlet on my turbo (of course as its a stock comp cover).

Are you goals 280rwkw and as stock looking as possible or 300rwkw and a little consideration for stock but not too worried? That will answer your question I think.

From my other thread in this section, it doesnt look like many people have gone past 280rwkw on the factory intake pipe, even if it is sleeved. I hope to do so next week.

[MrTerry]

Thanks for that good to hear what you've learned.

Well if the 2.5 is too restrictive i guess ill need a custom intake regardless if i go the 2.75 or 4.

I havent heard of anyone mention a power difference between the 2.75 and the 4, have you?

[GTScotT]

Firstly, if you are going to get the 3076, you should get the surge ported .6 AR front cover.

Secondly, I believe the 2.75" version is a .5 AR front cover. Similar to that found on a 3071.

Now, from all the variations of this turbo we have seen people use, the best option is the surge slotted .6 AR front cover. You will make the numbers with this and you will sound like a semi spooling up behind everyone. The 4" intake is honestly a PITA IMHO also. When I had my HKS 3037 (same turbo) I had it with the HKS only 80mm front cover. It is the same one as used on the garrett yet with the 4" snout cut off and a 80mm (3.15") snout bolted on. I would not even start to dream of bothering to make something to replicate this.

However - the turbo I always wanted to run was a 3071. The 2.75" .5 AR front cover is standard to that particular turbo and should not suffer from surge on the RB25. You are likely to be hard pressed to hit the 300rwkw mark as easily, however you will pick up some punch in the lower RPM.

For reference, see usmair's thread of his GTST with 3071 (.82 IW rear housing):

http://www.skylinesaustralia.com/forums/29...l&hl=usmair

See also:

http://www.gcg.com.au/index.php?page=shop....t&Itemid=53

[discopotato03]

I'm filling in the gaps by using "the force" but id does make sense .

What Garrett call the GT3076R , the real one anyway , was a turbo developed by Garret for HKS and it was called GT3037 . The GT3037"S" came with a port shrouded version of Garrett's 0.60 A/R T04E family of compressor housing .

Now HKS always used their own non Garrett turbine housings on 3037's and they tend to be more compact that the ones made by Garret later on . Also virtually all HKS GT30 turbine housings use the smaller more compact T25/T28 flange size , the exceptions were the GT Pro S turbine housings in IW form for RB20/RB25 and they had the "T3" flange .

Anyhow what happens when you build a turbo with a healthy sized compressor and a compact responsive sized turbine housing is compressor surge . By fitting the surge slotted/port shrouded compressor housing you can make an "all rounder" turbo meaning it doesn't matter if you use small turbine housings because the comp housing resists the compressor surge . HKS made GT30 turbine housings from I think 1.12 A/R right down to 0.61 A/R which is quite a variation in sizes . Believe it or not people used to use 0.61 housings and GT3037's on CA18's and SR20's to make a 300 Kw turbo spool up reasonably early .

HKS also had a range of compressor trim sizes in GT3037s , 48/52/56 trims but Garrett usually only brings in the 56T ones . The other year I did some research into the 52T ones and now they are available here as well .

HKS did offer non port shrouded comp housings on 3037's but I think they were aimed at 2L four cylinder apps ie SR20's .

I think the only version that didn't have a port shrouded comp housing option was the smallest 48 comp trim version but AFAIK they are out of production now .

Anyway your call , Garrett make T3 flanged GT30 IW turbine housings in 0.63/0.82 and 1.06 A/R sizes . If you were going to use the 0.63 one then I think you'd need the port shrouded comp housing to avoid compressor surge where you could possibly get away with the normal one using the 0.82 turbine housing .

I'd always grab the port shrouded one where possible because I think it has some performance enhancements , also if you hate lag and opt later for a smaller turbine housing you've got the surge issue covered . As others have said you can fit a reducer from 4 to 3 inch right at the turbo and probably not lose anything in an 80mm MAF system .

If you are not chasing every last kw with big turbine housings you can opt for a 52 comp trim GT3076R , it has a slightly better map than the 56T version and is supposed to be a bit more responsive all else being equal .

You call , A .

[MrTerry]

Thanks for all the replies guys, extremely helpful, ill have a think about it all and work out what i want.

[darrinspencer]

I run the 4" anti surge inlet.

Alot of people say they sound loud as they spool, but I believe that is to do more with type of filter you have.

I still run the factory airbox and panel filter, so no pod.

The induction noise is no louder than the stock turbo with airbox. When I first got my car it had the stock turbo with a HKS mushroom pod filter and it was very loud. I removed it with 2 days of owning the car.

Attached are couple of pic's of the inlet. 3"-4" reducer on turbo inlet, 3" 90deg alloy bend and 3" 45deg silicone bend onto airflow meter.

Pic's do not show engine breather return and bov return, but hey now welded into the inlet

If you need more pic's or where to get bits that do not come with the GCG kit, PM me

[juggernaut1]

I havent heard of anyone mention a power difference between the 2.75 and the 4, have you?

Refer to the HKS website - the 52 trim 3076 is available in 2.75 non-surge or 4 inch surge.....from memory the bigger 4 inch surge was rated at slightly more power - a difference that might be carried across to the 56 trim 3076.

Edit,

Here's the link - you will note the 4 inch cover is rated at 10hp more that the 2.75 inch cover in both the 52 trim and 56 trim.

http://www.hksusa.com/categories/more.asp?id=1092

Edited October 7, 2010 by juggernaut1

[MrTerry]

Thats excellent! thanks darrin, check your PMs

[MrTerry]

Refer to the HKS website - the 52 trim 3076 is available in 2.75 non-surge or 4 inch surge.....from memory the bigger 4 inch surge was rated at slightly more power - a difference that might be carried across to the 56 trim 3076.

Edit,

Here's the link - you will note the 4 inch cover is rated at 10hp more that the 2.75 inch cover in both the 52 trim and 56 trim.

http://www.hksusa.com/categories/more.asp?id=1092

ah interesting! thats good to know, thanks for that.