500HP target turbo - GTX30 vs ?

[Billman]

@Repo

Where do you get 2 bar boost on forth or fifth gear with a turbo with 60/85 compressor and 70/60 turbine and what AR Exhaust housing? (Cams 7a reclocked).
I would like to know it if you have experience.

[repo]

which specific turbo are You referring to?

A friend of mine took 780Nm with super40 from 2.2 liter. I think he had 2 bar around 3500rpm. But it was with 7a cams.

I haven't used 7a for anything since I realized the gain at the top end is not worth the loss in spoolup and midrange, so I have very limited knowledge of 7a based setups.

[Billman]

About my hybrid hx35/40. Have a bit big turbine housing right now but I just want to see if that's what I am seeing is ok.

[URQguy]

The difference in pressure from the collector to the turbine inlet is trivial. The usefulness of turbine inlet pressure is not however. It is the best tool for figuring out if your wheels are matched appropriately. Who cares how everybody else measures it. Just do it the way the manufacture recommends, and you will be golden. I would keep an eye on that key piece of data, even if others dont know what it means.

The problem with these small turbo shops like CT, PTE and HTA is that they are just blindly sticking compressors on Turbines and hoping for the best. They are not multibillion dollar companies with liabilities, engineers and lawyers. They are a small 30 person shop at the most, churning out test turbos for people to try at 1300 Euro. No maps on either hte compressor or turbine...

The majority of hte people that will spend 1600 dollars on a turbo will also be on Stand Alone. If that is the case, Flat foot shifting and anti lag can be used to combat the intertia lost. Personally, I think that is a hoax. THe tiny mitsubishi evo 5 turbos had only titanium shafts.. The weight saving that close to the axis of rotation would be negligable. Those were journal bearing turbos as well. I wager a Titanium oxide turbine would lose less rpm between shifts on a dual ceramic bearing center section than a titanium shaft on journal bearings.

Sure PDK's and sequential transmissions are out of the old school realm, but that is a tiny share of the market. Companies like BW and Honeywell are making turbos for modern cars. THey are looking at the next 10 years of tuning, where EVO's are on dual clutch transmissions, 911 turbos turning 10's stock are running PDKs, and it is becoming harder and harder to get a 6 speeds. Even slushboxes these days shift faster than a H box.

I think my opinions have been expressed. It will be interesting to see where the turbo market goes in the next 2 years. Cheers!

[Billman]

I was talking about the Evo 6 Tommi Makkinen Edition had Titanium turbine impeller but it was prone to break as it was the case with Nissan Skyline with Ceramic impeller.

[A80Avant]

which specific turbo are You referring to?

A friend of mine took 780Nm with super40 from 2.2 liter. I think he had 2 bar around 3500rpm. But it was with 7a cams.

I haven't used 7a for anything since I realized the gain at the top end is not worth the loss in spoolup and midrange, so I have very limited knowledge of 7a based setups.

3500rpm and 2bar from a super40? with what hotside and which gear was the pull made?

it was statements like these that made me try the super40 and then realise that you either need to invest 10K euros on engine parts to make the turbo have such small amount of lag, OR it is just not possible.

on normal ADU cams and head, the super40 with 0.70 bullseye hotside does not give you 2bar on 5th gear(let alone 4th) which is the usual gear that dynos are done, sooner than 4000rpm.

I used to get a slow increase in boost with that turbo and spec on 5th gear at somewhere around 3500rpm (around 0.7-0.8bar) and got into action after 4000rpm.

With 7a cams and 2bar on 3500rpm even on 5th gear, my personal experience says that is impossible on an otherwise non ported head, non tubular manifolds, and a catted 76mm exhaust.

[Faheemo]

You can hold 35psi to redline with a 30r on stock 3b/aan cams, but throwing 7a cams on a 20vt with tube headers and an intake manifold will result in a taper to ~ 28psi by 8500, regardless of wastegate settings.

I dont understand this , why would an engine with 7a cams not be able to hold as much boost as a car with stock cams ?

[diesel des]

The better top end cams allow the engine to out breath the turbo so boost falls off.

[Billman]

Think the following: boost pressure is the amount of pressure the engine sees but also shows the amount of air that engine can't process so it builds up.

[mastermind]

Now that's a lot of info to digest thnx Gentleman.

My target is 550 HP but looking for the spools similar to my GT3071/KKK 0.63A/R 50 Trim which I believe spools very well for my usage, however as I mentioned earlier the greed for more power mainly lead by my competition/buddies at the Hillclimbs with their Evos and Scoobies, but at the same time I dont intend giving up my daily driver ability of the S2.

I figure the only way to achieve this is to use a newer technology turbo, the GTX caught my eye, but it looks like the GTX 3071 although giving me the similar spool will probably give an extra 50HP, and then I had to ask my self if that was worth all the effort. So it looks like the new BW EFR 7670 is a better option than the GTX 3076, with better spool and is capable of reaching my stretch target figure of 550HP.

I'm not keen on changing the RS2 cams as I like the compromise they offer over the 7a's. I have just started the install of Wagner Tuning's short Intake kit and it now looks like I may have to be back at Wagner for the SQ manifold with T4 flange to get the best turbo for my usage.

All this will only work if my tuner does a good job though The ability to bring in the turbo progressively and not just shut the N75 until peak boost is reached is very important. I love lots of timing and only use race fuel( similar to Optimax 100) here is SA, never pump fuel which also helps.

[A80Avant]

i dont have a much different setup than yours(or as you plan to do it at least).

SQ EM, wagner inlet, GT3076R 0.82AR turbo. 4th gear 2.1bar @ 4000rpm and 3d gear @ 4250rpm.

ADU cams and head, with no porting and 76mm downpipe, twin cats and 70mm exhaust with 2 silencers. (custom made).

i believe that if i were to change the hotside to 0.63AR i would get much closer to my 3071R 0.63AR setup which i had(but with OEM Rs2 EM and OEM inlet) and the car would spool much faster. However the downside would definitelly be a fast reduction of power towards the top end, along with higher EGTs.

JP here used a 0.63ar hotside on the 3076 and managed to make 528hp on 7a cams BUT used a ported head with the .5mm larger valves as well, and OEM EM. (AAN inlet).

i was about to buy the 0.63ar to fit to my turbo, but thought to leave it and instead get a head ported and prepped for the future to give me more overall power per bar of boost and compensate for the later spool that the 0.82ar gives. If i end up not liking that, ill buy the 0.63ar then to fit.

The 0.82ar option will allow to eliminate the surge that the 3071 gives and produce close to 500hp, with the cost of more lag than the 3071 which is noticable.

[diesel des]

A80advant, I have a .63 gt30r housing if you want to try it....

[A80Avant]

is it T3? if so, how much would you sell?

[diesel des]

If you want to just try it just pay postage both ways. If you want to keep it we could work something out. Yea t3 flange. I also have the .82, and am interested in the difference between the two. But the engine this turbo is for still hasn't the urq back from painting.

[A80Avant]

pmed you