Whats everyones opinion on running a big holset turbo with basic Rb20

[Got2BeBoosted]

Ok i have a rb20 with lots done to it cooling and fuel wise are all good to go, still stock turbo but i have a custom stock Exhaust Manifold with external built into it and I'm going to be most likely buying a He351cw holset right away and its quite a jump from stock turbo but i wanna go big !! Has anyone ran one of these on stock internal motor??

Would this be a little to extreme for stock in terms of spool up? or would it be just right i wanna build the motor eventually too but for now i just want to get a whole new setup on it. i already know this turbo will bolt right up pretty much exactly the same as the stock one besides different down pipe and only oil cooled.

I'm not sure about the oil feed situation though with one of these turbos cant seem to find a strait answer on if it should be restricted and if i do jump to such a big turbo whats an safe low boost for something like that on a stock motor?
i already run 14.7psi on my stock one which i have been doing for the last 2 years with no problem but there is suck difference in size from the two.
Any info be great guys!!

[Alak]

What other mods do you have on the engine?

[Got2BeBoosted]

walbro255,FPR, oil cooler,3'' rad,FMIC, 3''strait pipe exhaust,mines ECU, greedy Profec B spec 2,Splitfire coils ,all the gauges i could need to make sure everything is running ok just want to get a turbo setup running for now than tune it and injectors later.

[Alak]

Keep the boost down to a very minimum. Even at low boost you are moving more volume than a stock turbo. I can't comment on if its laggy or not because I've never personally run a holset. If its sized correctly it should work fine.

[Got2BeBoosted]

what do you consider the very minimum boost? i don't wanna blow anything up, i don't know the exact size of the turbo but I've been told it equivalent to a GT35.

[Alak]

Its hard to say because I don't know. But this huge turbo could put out the amount of volume at 5PSI that your stock turbo will put out at 14PSI. You can google the compressor map and it will tell you the flow rate at a certain pressure, and you can compare it to the stock turbo compressor map and adjust it accordingly.

The engine will need a lot of work to support what that turbo can put out. In fact, I have an RB25 on my garage floor that someone tried to run a holset on, and Cylinder #3 is missing.

[Got2BeBoosted]

Yeah I'll have to take a look for them compressor maps just to be sure just want to get err running with it on that I'll be taking the motor apart and doing up the head and a good tune and injectors.

[99_SI]

Personally , I think holset are junk. See a lot of them fail at the shop on big trucks. Plus, only oil cooled...hence the failure rate.Stick with garret or Borg-Warner.


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[Got2BeBoosted]

I'm pretty sure the reason they blow up is they run big boost all the time on big trucks with holsets that are usually oilfeild, I have replaced plenty of them at my shop.. but for a car that isn't gonna be pushing crazy boost it should be fine. If i could afford a Borg-warner i would haha.

[Alak]

Borg Warners are the cheaper of the turbo brands when it comes to pricing. Oil cooling doesnt have a whole lot to do with failure. Ive seen 2500HP Diesel engines running 50psi and have no water cooling. Turbochargers typically fail when you run them beyond their designed perameters.

[Got2BeBoosted]

I'd have to agree with that deffinitly do you know if you can run an external wastegate with a Borg-Warner even if they come with internal gates on them?

[99_SI]

Gotta run a VGT, nevermind internal/external.


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[Alak]

You should be able to change the turbine housing to an external gated style.

[ToroGTS]

I wouldn't go ahead with this man.... That turbo won't spool up till like 5k rpm, so though you might make decent power at your peak, you will be slow to get there and it will fall off after like 6k rpm due to poor head flow. To get it to run decently you will need bigger injectors, a tunable ECU which wont be cheap and add tuning cost on top of that, good sized intercooler ect. You would be much better off to get a smaller turbo that will support 350-400 whp at 15-20 psi, with all the supporting mods above, that will spool up by 3.5 or 4 k rpm and make similar top end numbers, the only difference being ecu tuned differently to handle higher boost pressures/air flow. Peak boost PSI is not the make or break of an engine, its the handling of air/fuel mixture and ignition timing. Rb20's can easily take 20 psi of boost, but it needs to be matched with a solid 11ish:1 air/fuel mix and proper ignition to make sure it doesn't just melt through your piston head, or detonate so violently it bends your rod or otherwise blows our your bottom end.

[merkmerc]

I wouldn't go ahead with this man.... That turbo won't spool up till like 5k rpm, so though you might make decent power at your peak, you will be slow to get there and it will fall off after like 6k rpm due to poor head flow. To get it to run decently you will need bigger injectors, a tunable ECU which wont be cheap and add tuning cost on top of that, good sized intercooler ect. You would be much better off to get a smaller turbo that will support 350-400 whp at 15-20 psi, with all the supporting mods above, that will spool up by 3.5 or 4 k rpm and make similar top end numbers, the only difference being ecu tuned differently to handle higher boost pressures/air flow. Peak boost PSI is not the make or break of an engine, its the handling of air/fuel mixture and ignition timing. Rb20's can easily take 20 psi of boost, but it needs to be matched with a solid 11ish:1 air/fuel mix and proper ignition to make sure it doesn't just melt through your piston head, or detonate so violently it bends your rod or otherwise blows our your bottom end.

best bet is to go with the he351ve (vgt turbo) either build a solid arm you can adjust for the exhaust side then tune the exh side to the way you want . or build a controler with an internal waste gate to control the exhaust side in relation to boost for quick spool and then when in boost have the exhaust side get big for less back pressure . The dsm boys have been doing this for years . The turbos can be had for CHEAP . Its what i put on my rb20 in in my falcon and built my own vgt control with the use of a internal wastegate which is adjustable via a gm boost controller solenoid which is ran off a sub injector map from my emanage ultimate .
Some good links on it
http://www.dsmtuners.com/forums/cust...ontroller.html
http://www.realhomemadeturbo.com/for...hp?topic=477.0

and my lil deal bare with me its an old pic from when i was fabbin every thing