Rb25/vg30 Hi-flow Turbo: Results/comparison

[Turk]

?

[SECURITY]

i just had my slide turbo rebuilt by GCG with a GT core, not the regular core they put in their hiflows.

boost comes in so much earlier. with the slide turbo i'd see around 5psi by 3500-3800, with the garrett one i see 5psi by 2600-3000. that was probably due to slide over-boring the housings though (which GCG had to re-shim).

ill be getting it tuned soon so ill update in this thread.

[MZTRBO]

Hey Security

Any results yet?

[SECURITY]

nah i havent had the car tuned, maybe over the next few weeks.

ive used my old tune with the gcg turbo and im making around the same power as i was on the slide turbo at 15psi, with the gcg turbo on 12psi.

ill be getting my afr's checked up soon so ill update when i do.

[SECURITY]

ummm what is the ghetto mod, I've had my 33 turbo HF/BB through GCG and am going to have the VG30 Housing machined to it, I'd love any advice I can get

cheers

the vg30 exhaust housing will gain you around 10-15kw at the most. its probably not worth the trouble of spending $150 on machining then having to take the turbo out and re-fitting it etc.

[SmittyR33]

I've got a GT3071 from GCG. Its got an internal gated r33 rear housing that has been ground out. It pumps 15psi by 3300rpm and it made 230rwkw on the dyno. I was hoping to hit the 250rwkw someday. So from what I have read, a set of cams will get the turbo spooling earlier and maybe get me to 250kws?

[MZTRBO]

Im taking my car back to the tuners on monday so i will have new results..i made 235rwkw with one of these r33/vg30 hybrids on an auto and have now changed it to a manual. I'll let yous know how I go.

How does everyones turbo with the vg30 rear housing come onto boost...progressively, rapidly, instantly???

Just curious as my turbo comes on rapidly/aggresively like its a bloody big turbo. I know a few reasons why this is happening just wanting to know everyone elses experience.

Cheers

[Turk]

i have the rb25 hf turbo with vg30 op6 rear housing cant get it to stay on 15psi boost getting knocks going to 16-17 psi been back to the tuners 3 times cannot get tit right, on the dyno its perf 15psi boost making 252rwkw take it on the road spikes boost and knocks everything done probperly and double checked. dont know how to overcome this. even low boost which is 10psi will boost to near 14. even when boost is of it will boost to 14psi cant figure it out

[Cubes]

Turk,

Most likely a dump pipe design issue.

[skylinecouple]

This is the same problem I had with GCG hi flow. Can't put more than 15deg. into it or PING ! Give up, the hi flow is overrated. I strongly suspect different wheel combinations were used by these companies at different times, hence the varied results.

[Tangles]

I strongly suspect different wheel combinations were used by these companies at different times, hence the varied results.

+1

my Slide stnd highflow comes onto rapid boost by 2700rpm, pulls kinda' torquey & sees full boost another thousand rpm higher.

15psi no knock, piggybacks., but was dropping boost up in the top end

now added a plumback bov and awaiting a hks actuator so will retune when possible.

security Id say you definately had a dud-machined slide highflow

sounds like you are happy with the gcg - was it an expensive exercise? pm me please if you dont want to share the gcg rebuild cost to all and sundry......

[Al]

Im taking my car back to the tuners on monday so i will have new results..i made 235rwkw with one of these r33/vg30 hybrids on an auto and have now changed it to a manual. I'll let yous know how I go.

How does everyones turbo with the vg30 rear housing come onto boost...progressively, rapidly, instantly???

Just curious as my turbo comes on rapidly/aggresively like its a bloody big turbo. I know a few reasons why this is happening just wanting to know everyone elses experience.

Cheers

When i had my high flow it came on like a light switch. If i was in 2nd gear (manual), cruising at 40km/h, then stabbed the throttle, ass end would instantly light up and shift left. Also felt laggy for such a small turbo, but made 270rwkw@16psi with Poncams and headporting.

Thinking the high flow was a bad turbo combo, purchased 2nd hand, i bought a new HKS GTRS; made 268rwkw@18psi, response was a little better, but still not what people were talking about. After a few months i decide to put my mate's exhaust on my car and the results were instant. The results were so good that the tune jumped to a different load band on the ecu.

So the exhaust was the cause of my turbos acting like big hp units (lag, lag, lag, switch, instant power). Even though it flowed up top, for some reason it was restrictive below 3000rpm. I now have a feeling that my so called "performance" cat was mainly to blame, so i'll be doing another comparison, at a later stage.

Comparison Below:

Blue = New Exhaust system (Apexi)

Red = Custom Exhaust (Possibly restrictive due to the CAT)

[Sambo33]

i have the rb25 hf turbo with vg30 op6 rear housing cant get it to stay on 15psi boost getting knocks going to 16-17 psi been back to the tuners 3 times cannot get tit right, on the dyno its perf 15psi boost making 252rwkw take it on the road spikes boost and knocks everything done probperly and double checked. dont know how to overcome this. even low boost which is 10psi will boost to near 14. even when boost is of it will boost to 14psi cant figure it out

i had the exact same problem with mine, my tuner couldnt get a decent tune due to this. it turned out that the place that built my turbo had not machined the wastegate to match the rest of the turbo, so it had to be sent back and done again

[MZTRBO]

When i had my high flow it came on like a light switch. If i was in 2nd gear (manual), cruising at 40km/h, then stabbed the throttle, ass end would instantly light up and shift left. Also felt laggy for such a small turbo, but made 270rwkw@16psi with Poncams and headporting.

Thinking the high flow was a bad turbo combo, purchased 2nd hand, i bought a new HKS GTRS; made 268rwkw@18psi, response was a little better, but still not what people were talking about. After a few months i decide to put my mate's exhaust on my car and the results were instant. The results were so good that the tune jumped to a different load band on the ecu.

So the exhaust was the cause of my turbos acting like big hp units (lag, lag, lag, switch, instant power). Even though it flowed up top, for some reason it was restrictive below 3000rpm. I now have a feeling that my so called "performance" cat was mainly to blame, so i'll be doing another comparison, at a later stage.

Comparison Below:

Blue = New Exhaust system (Apexi)

Red = Custom Exhaust (Possibly restrictive due to the CAT)

Very interesting Al, When I was completing my man conversion i noticed that half of my hiflow cat had colapsed. I also have a very quiet = restrictive in most cases exhaust. Its a trust system with two oval mufflers.

I get the exactly same ting you mentioned lag,lag bang needle redlines. It does rev nice as i have a very light weight fly wheel.

What cat were you using

Cheers

[dead32]

this is exactly what worries me with these highflow options, the varied life of the turbo's, dodgy machine work and general power differences all throw me off. i mean they charge right on the money for a garret option and lets face it theyre reusing old bits, its more of a scrapy turbo throw together... i do however like the ease of fitment.

[Sambo33]

this is exactly what worries me with these highflow options, the varied life of the turbo's, dodgy machine work and general power differences all throw me off. i mean they charge right on the money for a garret option and lets face it theyre reusing old bits, its more of a scrapy turbo throw together... i do however like the ease of fitment.

thats what i like about it too, and the fact that they look totally stock in the engine bay. although people who i know personally who have highflows have never had a problem, ive only read the horror stories on the forums here.

[Al]

this is exactly what worries me with these highflow options, the varied life of the turbo's, dodgy machine work and general power differences all throw me off. i mean they charge right on the money for a garret option and lets face it theyre reusing old bits, its more of a scrapy turbo throw together... i do however like the ease of fitment.

Not really.

All bushes, wheels, etc are new items only the housings are std/old, but even these are modified to fit the new wheels.

On the other hand you can purchase a 500hp bb core and modify your exhaust and compressor housings to fit. Will be no different to a new Garrett turbo (if done properly), but still retain you factory housings; or at wost case, you could also change the rear housing.

[Al]

Very interesting Al, When I was completing my man conversion i noticed that half of my hiflow cat had colapsed. I also have a very quiet = restrictive in most cases exhaust. Its a trust system with two oval mufflers.

I get the exactly same ting you mentioned lag,lag bang needle redlines. It does rev nice as i have a very light weight fly wheel.

What cat were you using

Cheers

Hey Lizzy/Daniel,

I too had a super light flywheel (4.7kg) and once on boost would race to redline very fast.

The cat i was using was a generic "performance" cat, purchased 5yrs earlier, from the local exhaust place. Hence why i think the cat was my main problem. The rest of the exhaust consisted of one long "hotdog", two oval mufflers, and a VT commo tip (attached to the rear muffler) . The mufflers were only about less than 10,000km old, and were 3" diagonally straight through items (ie: you can see through the muffler, but the baffle pipe goes through the canister diagonally; not your typical "straight through" cannon style muffler)

I am currently building a new engine for my car, but once it is complete i will be adapting my old custom exhaust to my current dump and cat. I will then do a back-to-back comparison with my newer Apexi exhaust system. If the loss of power with the old exhaust is minimal (5-10rwkw), i will keep the custom exhaust as it is alot quieter and more discrete.

[R33GOD]

i just sent my slide hiflow back to be fixed. it blew and was only running 16 psi. throttle was no more than 1/4 when it went on me. hopefully when it comes back its all running fine. i think il set the max boost pressure to 15 this time just to be safe... well safer i hope

[Al]

R33GOD

Why limit yourself because of a faulty product?

Not saying that Slide turbos are bad/faulty, as i have had good experiences with Aaron (Slide). Sometimes shit happens and one or two go bad; i know i am in the technology trade. But when you get the replacement unit, don't hold back, it should be good to at least 16-18psi, if it fails then ask for a refund.

I know that my high-flow turbo ran out of puff at anything over 16psi (ie: the increase in rwkw did not justify the increase in boost). And with my level of head work, the turbo was limited to 270rwkw. On a std head, i would not expect to see over a genuine 250'ish rwkw.