Jump to content
SAU Community

Recommended Posts

Here is my little story. I have been wondering the same thing the last 6 months or so. This is what I have found.

I bought my gtr with plain bearing -5's. Now with

Cams, 10.25 @ 292

Good after market front mount

Very good fuel

Stock dumps

Stock but ported exhaust manifolds

After market exhaust

After market ECU

Fuel systems to support anything I threw at it

Made around 490 rwhp on around 20 psi. Boost control was rubbish. Needed one solenoid per turbo and a 32x32 table just to get any descent control.

If I rung its neck.... (shut the wastegates) it would spike to 2 bar as it came on to boost and 22 psi at 850rpm it would make 530 rwhp. Rubbish.

Now I thought that this was under powered. So made some 2.5inch dumps. No difference

Shortly after one turbo died.

I bought some shiny new -10's.

Made some 3 inch dump pipes. Twin 3 inch front pipe to single 4 inch system.

Engine now makes 400rwhp on 10psi. Much better :)

Bloody thing hits another brick wall at 480 rwhp!!!! Regardless of boost levels. Regardless of ignition timing or fueling etc.

Now. I believe its the standard exhaust manifolds. I really do believe that is the key to making big power out of these turbos.

At the moment I am currently fitting a single turbo charger. Its the only thing I am changing so it will be a reasonable back to back.

Has any one else seen anything else similar?

When my car was on the dyno a few weeks ago we went from 1.7 to 2.0 bar. I made an extra 12 kw (414rwkw) or something stupid so we pegged it back to 1.7 bar. I think my exhuast is too small but also I reckon my head port doesnt match my setup. Its a little lethargic down low but doesnt make mega numbers up top.

Are manifolds stock or port matched. N1GTR's manifolds are standard and makes more power then that.

Those 292 cams are bloody MASSIVE!

Here is my little story. I have been wondering the same thing the last 6 months or so. This is what I have found.

I bought my gtr with plain bearing -5's. Now with

Cams, 10.25 @ 292

Good after market front mount

Very good fuel

Stock dumps

Stock but ported exhaust manifolds

After market exhaust

Do not just keep throwing money at it. Find a real mechanic if you cannot get the thing to work.

You have not mentioned anything about the motor itself. What sort of head work do you have to support 292x10.25 cams and what sort of motor have you got that would do the 10,000rpm those cams imply?

If the answer is none you have some major issues. I am horrified of the thought of this thing.. I would personally put pencil to paper and plot exactly what I want from it and the setup I anticipate will get me there. I would then pull the motor out and strip it back to a long motor, refitting only parts that suit what I have set out to plan.

No number of band aids, double sided tape, sikaflex or zip ties will stop cut wrists from bleeding out. Get onto a real fix, maybe even start your own thread in the members ride section to properly introduce yourself and the car so you may start an active discussion to help your cause.

It honestly does sound like you have a hungry money pit, see below.

post-43588-0-51473600-1294532701_thumb.jpg

Gav how long have you had your Tomei manifolds on your car? I have been through two sets. Cracks, holes blown in runners and the last set didnt make it to 2000 kms. Alot of that was on E85 (second set) too.

Gav how long have you had your Tomei manifolds on your car? I have been through two sets. Cracks, holes blown in runners and the last set didnt make it to 2000 kms. Alot of that was on E85 (second set) too.

I'd be having a good look at your tune, and your EGT's. These manifolds shouldnt crack if your tune was correct for normal unleadded fuels.

While switching to an alcohol based fuel in theory lowers combustion temps and EGT's, the way many people are setting up their E85 engines with higher compression means the common target afr charts dont produce an EGT that is in the safe range. Ive heard stories of melted exhaust valve guides in alcohol based fuel engines that run compression at the higher end of the scale, so it stands to reason that a moderate increase in EGT's could certainly cause stress cracks in in a manifold.

an amazing difference in midrange!

Damn right it is. If you look up the hot side of the turbo's they are exactly the same.

Gav, were the turbo's modified in anyway or were they straight out of the box and bolted up?

I'd be having a good look at your tune, and your EGT's. These manifolds shouldnt crack if your tune was correct for normal unleadded fuels.

While switching to an alcohol based fuel in theory lowers combustion temps and EGT's, the way many people are setting up their E85 engines with higher compression means the common target afr charts dont produce an EGT that is in the safe range. Ive heard stories of melted exhaust valve guides in alcohol based fuel engines that run compression at the higher end of the scale, so it stands to reason that a moderate increase in EGT's could certainly cause stress cracks in in a manifold.

Thats a good point. My engine is 9.0:1 comp so it is highish. Next time I go back I might mention it to Yavuz (the tuner) and see what he reckons? Either way im back on ported stockers.

Gav how long have you had your Tomei manifolds on your car? I have been through two sets. Cracks, holes blown in runners and the last set didnt make it to 2000 kms. Alot of that was on E85 (second set) too.

Actually, I'm not overly impressed with the Tomei manifolds for that reason. I had cracks in the first set that I had welded. Then I found they had burn't through on the outside of the runners. I'm on my second set now and if these fail I'm going back to cast iron units.

On the graph I posted, I did forget to mention I'm running GTS-4 ratios. I'll track down an updated E85 dump graph showing the other set-ups with RPM on the X axis.

Ah already done...

Notice any difference?

It could be placebo but it feels like there is. But that could be just my head. I want to get another set and extrude hone them and really get it spot on! So many people swear by the stockers.... and going by Gav's post above me he has had issues with the Tomei's aswell!

RPM = (SPEED / 28) * 1000

to work out RPM from a speed based dyno plot, assumes 4th gear with 4.11 diff gears

This doesnt really work for mine, as I doubt my car makes 340rwhp @ 6250rpm. Its more like 7250rpm. Hmmmm.

It could be placebo but it feels like there is. But that could be just my head. I want to get another set and extrude hone them and really get it spot on! So many people swear by the stockers.... and going by Gav's post above me he has had issues with the Tomei's aswell!

Leave the things alone

Gav, were your -5's straight out of the box or were the tinkered with?

With the exception of HKS actuators they are bog stock.

These did need a freshen up with seals and other bits and pieces (maybe bearings) recently after around 5,000 km of mainly hard track time. Still have the same exhaust and compressor wheels 'tho.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • No worries at all 🫡 I think the most satisfying things to make are the little bits that are just impossible to find or they're no longer manufactured. Generally I always try to replace parts with OEM wherever possible. This little project is also great because it'll never see the light of day, but strengthen these brackets so it's not just relying on the little standard screws in the headlight plastic. As soon as I saw the standard brackets and screws I thought, "well I'm not going to install with just the screws, the plastic tabs will just snap off". It's crazy how expensive everything has become yeah. But I suppose that's supply and demand; granted it's a lot easier to get brand new genuine parts these days which is fantastic 😊, I don't have to get totally reamed at the local Nissan dealer ha ha We sure are lucky we have all these manufacturers making parts these days, a few really great Australian companies too like Platinum Racing Products and Fit Mint Automotive, what a time to be alive ❤️ . I've got my eye on the RB26 head by PRP as mine has a very fine hairline crack, so that'll need to be addressed some time in the future. If you have any requests or odd things to make feel free to let me know and I can have a crack at making replacement parts ✌️
    • Thanks for sharing this, and BTW if your headlights are in good condition they are worth thousands....you might want to consider replacing them with brand new LED ones like this (https://www.nengun.com/78works/full-led-headlights-r32-skyline) and making enough profit to buy a house in Sydney
    • I'm not sure what sort of shops are nearby, but I'd expect any reasonable exhaust shop could put a cat in it that will not restrict the power that engine makes. Otherwise, if you want to remove it, short lengths that replace the cat are readily available online, search for "de-cat pipes" or "test pipes"  
    • Howdy friends, So another weird one today, I was looking into replacing some broken clips holding the front grille for the R32 GTR (part number 01553-03831), and noticed the brackets which are supposed to hold the grille in place were also missing 😑. I do recall seeing this issue many years ago, but didn't fix it at the time. A quick look on eBay and I was able to find the genuine brackets, along with all the screws which suited the headlights (part numbers 26042-08U05,26092-08U05). Happy days!....  Once they arrived however there was an extra nut in the packaging which implied that there should also be a bolt or a stud, and sure enough, after a bit of searching I found this thread from 2013, and @Ants clearly shows a stud should be present. Reading around a bit more, it's possible the headlights on my car are the "povo pack" headlights as mentioned by @funkymonkey in this thread way back in 2008. This could explain why the studs are missing on my set of headlights. Looking at the headlight diagram I wasn't able to see a suitable part number for the stud itself. The headlight did indeed have a recess that looked like it would accept a stud, but interestingly no thread or anything obvious how the stud would be affixed to the headlight, I suspect it may have been glued in, press fit, or melted into the plastic at the factory. Another member may be able to clarify if they happen to have a genuine set of N1 headlamps. The only thing we have to work with within the recess is a keyway which likely is there to prevent the stud from rotating within the recess. In any case, back to 3D printing, I put together a model which acts like a pug with a friction fit inside this recess, making use of the keyway so it doesn't rotate while tightening a bolt. Printing in TPU will allow it to slightly swell making a nice snug fit without cracking the part. I've designed the adaptor it to accept an 20 mm M6 bolt (stainless with a cap head in my case), as opposed to the standard M5 stud and I made use of the standard galvanised split washer that came with the genuine brackets from Nissan. Once the bolt and screws were all in place, giving the bracket a gentle shake gave the classic "shaking the car" feeling, very solid, which gives me confidence this is going to be able to hold on much better than the janky solution which seems to have been here for the past decade or so. Overall I'm really pleased with how this turned out and maybe there are more people out there running these headlights without a centre stud at all! Link to the freely available model on Printables: Click here Regards, Sean  
    • Hey everyone, This is my first post apart of the introduction. I tried searching a bit on the forum but couldn't really get a straight answer. I got the car to my mechanic as I felt it being weak. It seems that it was missing on two cylinders due to the injectors. I had all my injectors clean and the car runs much better. The mechanic also confirmed my suspicions that the cat is clogged and needs to be tackled asap. The cat rattles a bit and the hot exhaust warning frequently lights up when driving after getting the injectors clean. In my introduction I was asked about what modification I might be interested in and mentioned a cat delete. From what I was told, this is not really beneficial on the RB20DE and there are more cons than pros.  Could perhaps anyone give some suggestions on what the best course of action would be since the current cat is toast and needs to be removed/replaced anyway? I can also sometimes smell a strong smell of fuel, but I'm not sure if this is related.
×
×
  • Create New...