Jump to content
SAU Community

Educated Guess At The Final Tune Results


Nismo 3.2ish

Recommended Posts

Things don't seem to be necessarily optimal, but I'm not expecting to see miraculous improvements in power - perhaps some improvement in power delivery if it turns out the intake cam proves to be excessively retarded in practice.

I also do not expect any real over all power improvements. What I have is plenty.

What I would like to know is, if you have your intake side retarded by 3 or 4 degrees and you advance it 3 or 4 degrees , there is 6 or 8 degrees difference, what would this do for the low end power gain at lower rpms.

Link to comment
Share on other sites

Never heard of an external wastegate opening due to exhaust pressure tbh, I'd consider it a design issue if it did - by function definition they are meant to block any flow until the reference pressures met targets - especially if it had both ports utilised.

If he is bleeding off a 12-14lb spring and has a higher than expected exhaust manifold pressure at wot due to a restrictive rear then the gate will crack open, no question. This always happens in this scenario, not the first time and it won't be the last.

With a larger higher flowing rear there will be a lot less manifold pressure at the same boost pressure, even running a 1.15 AR at 30psi I would expect to see less manifold pressure due to the lack of back pressure.

Link to comment
Share on other sites

Just curious, if it was getting valve float in the top end, would you/could you tune around it by dropping the boost and retarding the cams?

The dyno curve looks like it gets a wiggle on a touch, maybe not significant?

Link to comment
Share on other sites

Just curious, if it was getting valve float in the top end, would you/could you tune around it by dropping the boost and retarding the cams?

The dyno curve looks like it gets a wiggle on a touch, maybe not significant?

It won't be floating. I run the same cams, springs and retainers and have given my setup 30 psi.

Not sure how much more boost you want to pull out of it. It's dropping to 18 psi as is.

Link to comment
Share on other sites

I think we should stop theorising and wait for when it goes onto another dyno. Then we know what is what

Why? Just discussing what lith brought up. That's all. Edited by XGTRX
Link to comment
Share on other sites

I also do not expect any real over all power improvements. What I have is plenty.

What I would like to know is, if you have your intake side retarded by 3 or 4 degrees and you advance it 3 or 4 degrees , there is 6 or 8 degrees difference, what would this do for the low end power gain at lower rpms.

Theoretically yes but really this is usually the last thing you do after the rest of the set up is A OK.
Link to comment
Share on other sites

It won't be floating. I run the same cams, springs and retainers and have given my setup 30 psi.

Not sure how much more boost you want to pull out of it. It's dropping to 18 psi as is.

I think he was more leading towards that being a possible reason its like it is.
Link to comment
Share on other sites

How's the water Pete?

When is it booked in for the next tune?

Hi Mark, waters all good :)

Just waiting for some other work to be finished in the shop, not much use leaving it there until he can work on it , maybe another week or 2. Not just the tune to do and I can still use the car while I am waiting :)

Link to comment
Share on other sites

I've got to say I would be pretty unhappy with that boost drop.

Kind of like getting married to a hot Virgin, and then being told you have to use a condom for the rest of your life......

Yeah a bit of bummer :(

I will still take the Virgin , condom and all :)

Link to comment
Share on other sites

If it's the turbo selection that is causing these issues.... Everything else is irrelevant. See what the new tuner says.

Fairly narrow minded, all you can say is its the turbo. Its rated for over 700hp ffs, if there are no other restirictions it should acheive close to that.

Can u tell me why my engine with a .82 rear housing does not have this issue?

  • Like 1
Link to comment
Share on other sites

I am starting to agree with the plausibility of his theory - I wouldn't go so far as to say that's the issue, but.

You have a .82 open housing, a .84 open housing is a different beast and in most cases I would expect it to be more comparable in to a .6x open housing which would make people shit themselves if it was said that someone was going to put on a 3.2 litre aiming for 400kw+ on petrol.

When I first heard about this I thought the hotside was going to be too small and that was before I learnt it was a small divided hotside on it, I've never thought about or had to deal with a bad turbo match like this causing excess back pressure - I like to think all the things I have been involved with have quite well matched turbos and as such exhaust manifold pressure has tended to be sane and never thought about the effect on the waste gate but the more I think about it the more it makes sense. Always nice to learn something :)

Link to comment
Share on other sites

Fairly narrow minded, all you can say is its the turbo. Its rated for over 700hp ffs, if there are no other restirictions it should acheive close to that.

Can u tell me why my engine with a .82 rear housing does not have this issue?

Hope your right :)

I spoke to the bloke at Precision Turbo and he said it "should" not loose more than 50HP with the 3.2 . With some blokes taking these turbos up to 740HP with varied sized motors ? ?

Link to comment
Share on other sites

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

    • Suspension Component Question Looking for some feedback based on people's experiences! I know this has been loosely covered in other threads but I can't find any direct answers/experience. I'm up for some bush/rod replacements and was interested in a hybrid approach between hardened rubber and pillowball kit. Why not choose one or the other? Well, this is for my daily driver, which I track once or twice a year. I like a stiff car and a sporty feel but I don't want to compromise the chassis too much with 100% pillowball gadgetry.  I know from experience and a tonne of reading that not all components affect ride quality in the same way - eg. in my case, coilover top mounts should be hardened rubber as pillowball transfers way too many undesirable qualities and doesn't have much more upside than a good hardened rubber. But, pillowball tension rods translate to much better turn-in/steering response and make the car significantly sharper, without negatively impacting ride quality in a significant way.  I'm not TOO bothered by NVH (to a degree). So, with context out of the way, does anyone have any experience with a hybrid approach as mentioned above? I'm going to replace all components over time so am seeking guidance on: - front tension rods - upper camber arms - rear lower control arm - rear traction rod - rear upper camber arm Secondly, is there any reason why this is a bad idea? Or any other info/wisdom that I might not be considering. Cheers 🫶
    • That's good to hear I'll stick with the stock I hear they are good for 500hp and I'm only shooting for 350-400 once I can get this thing sorted and get to actually building it. 
    • The stock one will outperform any aftermarket standard position exhaust manifold. If you don't believe me, do a back to back test (same turbo, same boost, same timing) and you'll be super surprised.
    • Any recommendations on a decent replacement manifold that doesnt break the bank or require additional mods for the stock turbo setup? I figure if I'm going to pull the manifold off anyway to fix the studs might as well replace it. 
    • So I checked the turbo out today. Very minimum play at all just enough for the oil to take up when it's running. I did find an exhaust leak at the manifold. 1 stud all the way in the front is missing and the one all the way in the back is broken off. Front has visible signs of an exhaust leak. I'll fix that soon but that's not my problem still.  I also found that the nipple coming off the turbo had the hose capped off and a hose ran from the j-pipe by the bov going to the wastegate. I removed that hose and capped that nipple and put the turbo nipple hose back on the wastegate.  There was a ton of oil residue all through the charge side of the intercooler piping going to the throttle bodg. I'm thinking that's from the pcv. Doesn't seem to be coming from the turbo that was all clean on the pipes side.  Haven't had a chance to check fuel pressure yet, haven't had time been having to pull a lot of doubles at work. I did pick up some carb cleaner to clean the iacv but wanted to make sure I had a fresh gasket in case the old one rips when I pull it off.  I'm waiting on a MAF that was supposed to be here today but delayed to Monday. Have a double Monday and Friday and work all of next weekend so going to try to find some time in the middle of the week to try that out. Did about a 10m trip around the block today and towards the end the issues were coming back. Fingers crossed on this MAF but if not just going to throw a fuel pressure gauge in and see where I'm at.  Did notice today that I can definitely hear the injectors pulsing. Very audible clicking coming from them. Assuming that's normal? Should also mean CAS is functioning somewhat properly. After it warmed up when I started it the intermittent misfires came in again. Did start doing that before it was fully warmed up. 
×
×
  • Create New...