n1 turbos

[wrxhoon]

does anyone have n1 turbos in their gtr ?

i want to know at what rpm they spool up and how much boost do u run with them . tnx in andance

[Sydneykid]

Hi hoon, We have an R32 GTR with genuine (not copied) N1's. We have run up to 2 bar but much over 1.6 and they get inefficient, make more heat and not much more airflow. We have good support stuff, split dumps, adj cam timing, 9 to 1 compression ratio, V spec I/C, 4" exhaust and a highly tuned Power FC so they make 1 bar at 3,800 rpm. Which is better than the standard turbos did with the standard support stuff.

It's not all turbos, the support stuff has a lot more to do with response than people give them credit for. I can actually tune it to get boost even earlier but it looses a bit of top end when I do.

Hoep that helps

[benjiman74]

Sydenykid - Thats interesting, I have the same mods as what you've listed but they don't start boosting till well over 4,000rpm. It made 285rwkw @ 1.4Bar on Racepace's Dyno b4 Christmas with a pretty steep ramp in the middle of the curve. What power are u making on your n1's?

[wrxhoon]

benjiman what rpm do u get 1.4 bar at ? i get 1.2 bar at 5500 -5800 , i have genuine n1's had them rebuild by garrett . the stock ceranics i had spooled to 1 bar at 3500 - 3800

[benjiman74]

wrxhoon - i have r34 N1's and they hit 1.4 bar at between 5,000 - 5,250rpm.

Looking at Sydneykids post I note he has upped the compression ratio.

[benjiman74]

wrxhoon - I believe there is a few variations in the housing size of n'1's. Consequently some say they are super responsive but run out of steam up top while it appears yours and mine are laggier. I must admit that once on boost they pull clean to 8,000 rpm.

[Sydneykid]

Hi benjamin, there are a few things I need to clarify;

1. The split dumps are separated for 400 mm, not 200 mm like the off the shelf type.

2. The engine pipes are equal length

3. Standard GTR compression ratio is 8.6 to 1, we have increased that to 9 to1 by using the squish zones

4. I have tuned the PFC with a lot of ignition advance

5. The exhaust manifolds are ceramic coated, both inside and out

6. The turbine covers are ceramic coated on the outside

7. We run Elf LMS

8. The tappet clearances are very tight, for more valve lift from the standard cams.

9. The cam timing is nowhere near standard, we aren't allowed to use adj pulleys, so we have to correct it with other methods

10. I have sacrificed about 20 rwkw to get a better average power

11. We are at 308 rwkw at 1.5 bar

12. The average power from 4,500 rpm to 8,000 is over 250 rwkw.

13. The titanium exhaust is 4" from the join of the engine pipes, there is no cat and it has only one muffler at the rear

14. The injectors are running a lot more than standard base pressure, to increase the fuel atomisation at short openings

15. I have tuned the injector timing to suite the opening duration

16. The wastegates are using 1.2 bar springs

17. The spark plugs are indexed for orientation

18. The combustion chambers are polished and volume matched

19. The valve seats are ground to different cut angles than standard

20. The valves are N1 spec

21. The valve springs are N1 spec with pressure equalisation

22. The piston crowns are exactly the same dimension for all cylinders

23. The piston and their rings are matched to their own bore and the ring gap is 60% smaller than standard

24. The bores are honed to a selected pattern with a chosen stone

25. Bearing clearances are much greater than standard

There are probably a few more things I have missed, but I think you get the drift. There are so many things we can't do under the regs that we have to do a lot of things, the ones that we can do, to a minute level. This costs way more in time than you would bother spending on a road car, where I would just whack in a pair of high lift cams, port the head and get a better result. This engine would have cost $20K to build, if we had to pay someone to do it, and it is basically a "standard" engine.

Hope that clarifies

[benjiman74]

Syneykid - Thanks for your detailed response. A little more advanced than my RB26 with bog stock internals running on pump fuel!

Hope you can help with the following Q's:-

Can you confirm there are different r34 n1 housings or is this a myth?

Could some of my lag be attributed to the spring rate on the wastegate actuators?

Thanx in advance.

[lwells]

Sydneykid: What's the difference between stock 32 GT-R turbos and N1's like in terms of spool up?

Cheers,

LW.

[rb26dett]

ben...i may be wrong, but u should look at cam timing. after i put them on n my mechanic did his work on it, i found i practically lost turbo lags, but i am running stock turbos, which are supposed to spool earlier. also running power fc with avc-r, hks dumps and front and a custom straight pipe with just one muffler at the end.

[benjiman74]

I have adjustable cam gears that were altered to take out most of the bump I had in the middle of my curve and improved power by 30kw from 3000rpm and 40kw at peak. Like you i'm also running a power FC, hks dumps, single muffler, straight 3.5 inch system.

Seems like I have a lot of lag for the power its making - What are you getting out of your stock turbo's and at what boost level?

[rb26dett]

my turbos spool at about 2000rpm, making about 0.5bar at 2000. it hits 0.8 bar just before 3000rpm and makes its peak of 1.1bar at about 4000rpm.

i have no idea what's the cams set to cos my mechanic won't tell me. all i know is that the intake is advanced 5 degrees. that's all he tells me. no idea how much horses i'm putting out cos i've never tuned on a dyno. my mechanic does it all on the street and he says i'm in the 350hp range.

[jezzrrr]

my turbos spool at about 2000rpm, making about 0.5bar at 2000. it hits 0.8 bar just before 3000rpm and makes its peak of 1.1bar at about 4000rpm.  

i have no idea what's the cams set to cos my mechanic won't tell me. all i know is that the intake is advanced 5 degrees. that's all he tells me. no idea how much horses i'm putting out cos i've never tuned on a dyno. my mechanic does it all on the street and he says i'm in the 350hp range.

Do you mean in the 350KW range ? I am making 380HP at the wheels with stock turbos on my R34.

Jeremy

[Sydneykid]

Hi benjamin, you asked........

* Can you confirm there are different r34 n1 housings or is this a myth?

Sorry, I have no idea, I have never seen an R34 GTR N1 in the flesh, much less pulled the turbos off and checked their dimensions.

* Could some of my lag be attributed to the spring rate on the wastegate actuators?

It is a good place to start, if you have 10 psi springs they are going to start opening at around 5 psi. The older they get, the worse this problem becomes. That's why I always run a spring with a rate as close to the target boost level as I can get. That way the boost controller (whatever type it is) doesn't have to work as hard to bypass/limit the air flow to the wastegate actuator.

Hope that helps

[Sydneykid]

Sydneykid: What's the difference between stock 32 GT-R turbos and N1's like in terms of spool up?

Cheers,

LW.

Hi lwells, I think I answered that in an earlier post.........

"they make 1 bar at 3,800 rpm. Which is better than the standard turbos did with the standard support stuff."

Yep I thought so, does it answer your question?

[rb26dett]

jezz...i'm hoping it makes 350kw...but it is 350hp my mechanic said so i'm just quoting him.

[lwells]

Hi lwells, I think I answered that in an earlier post.........

"they make 1 bar at 3,800 rpm. Which is better than the standard turbos did with the standard support stuff."

Yep I thought so, does it answer your question?

Whoops, didn't see that

LW.