How to turbo your N/A

[blk94r33]

Mine runs fine like that (and has done for 20thou km), but if you are feeding it too much oil it would make sense that it would need a more serious drain.

Next time you have it off have a look at your bango bolt, it should have a pin sized hole in it (not completely hollow).

Using the standard banjo bolts, the hole size/s are alot smaller than the size of the bolt itself, half or there abouts...

Either way it's fixed now. New exhaust today. Standard dump and front, Magnaflow 3" cat, high-flow center muffler, 2.5" piping all the way to replace the current varying range that runs down as small as 2 1/4". Very keen to see how it goes afterwards.

[blk94r33]

Mine runs fine like that (and has done for 20thou km), but if you are feeding it too much oil it would make sense that it would need a more serious drain.

Next time you have it off have a look at your bango bolt, it should have a pin sized hole in it (not completely hollow).

Using the standard banjo bolts, the hole size/s are alot smaller than the size of the bolt itself, half or there abouts...

Either way it's fixed now. New exhaust today. Standard dump and front, Magnaflow 3" cat, high-flow center muffler, 2.5" piping all the way to replace the current varying range that runs down as small as 2 1/4". Very keen to see how it goes afterwards.

[SKiT_R31]

Why 2.5"? Even on stock dump/front I had a noticeable power increase going from 2.5" to 3" on my NA+T (felt looser/less held back and picked up top end) Also 3" bell mouth dump is only $100 which I would also recommend, high comp has lots of hot exhaust to vent!

Either way, keen for results

[SKiT_R31]

Related which just cropped up is this;

http://www.skylinesaustralia.com/forums/topic/369171-turbo-exhaust-theory/

Really good read imo.

[blk94r33]

Discussing the 2.5" vs. 3" exhaust in that thread at the moment...

[SKiT_R31]

Yeah just saw all that, a lot of the information on the internet is just re-preached 'yarns' without any understanding, but this is not one of them. Even with the stock dump/front pipe (2.5") a 3" cat back gives a very decent gain over a 2.5" system across the entire rev range (initial spool time, midrange AND peak power).

I used to agree with your point of view, thinking my N/A+T's would love 2.5" on 200kW+ (my goal), that if it can flow the power its good enough, but it really isn’t. There is so much free power just through efficiency that you are losing out on from stock exhaust. My R31 RB30e+t, R33 RB25DE+T both went from 2.5" systems (one press, one mandrel) with straight through perforated hot dogs and mufflers (not offset or chambered) and both had excellent gains in throttle response, delivery, just general engine feel and top end (not just the figure) with zero downside (even exhaust was roughly the same volume).

The car of course will drive well and will make decent power on 2.5", but the point is it will be better the entire range and make more power on 3". As the thread reports it is nothing like with matching N/A systems with exhaust velocity and backpressure trade offs (losing top or bottom end).

Another example is my daily, an R34 GTT - completely standard with nistune and 10psi gets 175kW at the wheels. I loaded the same tune onto a mates R34 which was identical (completely standard engine/cooler) on the same boost but with a 3" split dump, 3" cat and 3" cat back and it made 195kW at the wheels, completely different to drive; 1000x better in every way (except I like my daily silent).

Because of this I am forced to eventually get a CES turbo back system, not just for peak figure but for the entire drivable range.

You really can’t understand until you do it for yourself, now you have a 2.5" system that’s fine. Do all your other modifications, hit the bottle neck (and realise it’s the obvious next step for more power) and then move on, but the debate just seems to be for self justification more than anything (not meaning to be an asshole its just how I see it).

[blk94r33]

You really can't understand until you do it for yourself, now you have a 2.5" system that's fine. Do all your other modifications, hit the bottle neck (and realise it's the obvious next step for more power) and then move on, but the debate just seems to be for self justification more than anything (not meaning to be an asshole its just how I see it).

I didn't view the comment that way, so no offence taken.

I understand the idea behind the 3" vs. 2.5", and admitted in the thread, that more than likely i'll end up with a 3" system, for now at least i'm happy with the 2.5" set-up, it's dramatically changed the feel of the car, fixed the boost drop, yet keeps it very quiet and no drone. After driving/riding passenger in a mates' car with a 3" system and the basic mods, I hated the sound of it and the drone at ~2750rpm @100kph, with at high-flow cat, muffler and cannon, I know a better system could eliminate these problems, personal preference I suppose...

In the exhaust theory thread, it states bigger is better at the start of the system, so a 3" dump/front will be the next step provided I don't encounter detonation on the dyno. If with the exhaust dropped and a 3" front i see a ~+%10 difference, then i'll switch to 3", if i gain less than ~%10rwkw, then i'm not going to bother until I find the bottle-neck. 10 degrees ambient temperature and an average air filter would find %10rwkw...

[gts25]

Hi all,

I am currently in the middle of turboing my R32 RB25DE using R32 RB20 parts.

I am unsure what spark plugs are the best to use.

From what i have read in this thread most people have used plugs with a heat range of 7 but

if I check the NGK website, the NA RB25DE uses plugs with a heat range of 5 and the RB20DET uses a heat range of 6.

Does anyone know why I should be using plugs with a heat range of 7 instead of 6 (as per standard for turbo)

Thanks

Jason

[gts25]

Hi all,

I am currently in the middle of turboing my R32 RB25DE using R32 RB20 parts.

I am unsure what spark plugs are the best to use.

From what i have read in this thread most people have used plugs with a heat range of 7 but

if I check the NGK website, the NA RB25DE uses plugs with a heat range of 5 and the RB20DET uses a heat range of 6.

Does anyone know why I should be using plugs with a heat range of 7 instead of 6 (as per standard for turbo)

Thanks

Jason

[666DAN]

Your compression ratio is higher, so you need a colder plug. BKR7E will do the job

[66yostagea]

This is a great read for me. Two reasons,

I have and RS4 with Rb25DET. Was stock when bought 5 years ago. Have modded to 3" turbo back, JJ Bellmouth and Hi Flow Cat.

Great improvement was felt. Next up installed FMIC and Greddy copy FFP. with Pod, that really gave it some extra. Am very happy with the bang for buck.

I have a redP son. I got him a 25G Stagea with RB25DE. Little bugger now wants a (can't say the name) non Nissan. So I am going to turbo it and all the info is here. AFAIK there are very few N/A Stags in Oz This had been a personal import.. Have all the parts now except for the bigger brakes.

[gts25]

Your compression ratio is higher, so you need a colder plug. BKR7E will do the job

great thanks dan, will pickup a set of these plugs. will post up details of my conversion and how it goes when finished soon

[-Jimmy-]

This is a great read for me. Two reasons,

I have and RS4 with Rb25DET. Was stock when bought 5 years ago. Have modded to 3" turbo back, JJ Bellmouth and Hi Flow Cat.

Great improvement was felt. Next up installed FMIC and Greddy copy FFP. with Pod, that really gave it some extra. Am very happy with the bang for buck.

I have a redP son. I got him a 25G Stagea with RB25DE. Little bugger now wants a (can't say the name) non Nissan. So I am going to turbo it and all the info is here. AFAIK there are very few N/A Stags in Oz This had been a personal import.. Have all the parts now except for the bigger brakes.

What a lucky son you have.

[blk94r33]

Hi all, seeking opinions after a slightly disappointing result:

http://www.skylinesaustralia.com/forums/topic/249186-nat-power-results-na-t-turbo-conversions-only/page__view__findpost__p__5981406

In brief, the car made an overall low figure. AFR's "peaked" at around 8.5-9:1. After dropping the exhaust, removing the air filter, and seeing no worth-while gains in changing either (yet), and talking to the dyno operator, he said the next option is simply to take out fuel to find more power. But I honestly don't know why it's so rich? Other problem being boost gets unstable after 5000rpm, mechanical gauge goes from a solid 7 to flickering like crazy between 7 and 5 psi, which again could still be a rich mixture not burning properly?

Relevant mods: http://www.skylinesaustralia.com/forums/index.php?app=garage&do=view&id=1515

Ideas include:

-Too much fuel pressure (doubtful with a GTST reg, injectors, rail and Walbro GSS-341 pump)

-The AFM is still a N/A series 1 R33 item, is the turbo one different? Ie. the AFM hitting 5 volts too soon and ECU going into R&R?

And yes, i'm the muppet with the 2.5" exhaust, but dropping it at the dump/front pipe and removing the air filter made little difference. And at 138 kw I doubt it's causing problems anyway?

Open to suggestions ideas etc.

Cheers, Josh.

[WYTSKY]

I believe you do need the gtst afm as the na one is only used to measure atmospheric pressures and abit of sucking, but not positive pressures.

you should be getting about 150-160rwkw on 7psi.

[SKiT_R31]

Its a mass air flow meter, pressure has no effect. Also both N/A and Turbo AFM's only measure atmospheric pressure as they are placed before the turbo (aka out of boost), but putting them in boost makes no difference as 500CFM @ +14psi travelling at x speed is the same as 500CFM @ ATMO travelling at 2xX speed (for example).

Its all about the voltage range (which is the same between the 2 items), if his AFM is healthy it shouldn’t make any difference. It still wouldn’t hurt to swap it with another though as it still could be the cause, it could be because the AFM was already faulty and miss-reading, and the increased airflow is throwing it out more and more.

That said, my money is definitely on some sort of boost leak or R&R issue.

I once had a similar issue with an RB30e+t, couldn’t find the leak so I moved the AFM into boost as close to the throttle body as possible and it fixed the symptoms (though still slightly down on power as the turbo had to work twice as hard to produce the same boost) at least until I could find the cause.

What BOV are you using? Plumb back? I've known some ATMO's to leak boost and cause similar issues.

[blk94r33]

Using the stock plumb-back BOV. Might try blocking/disconnecting it next run to see if it makes a difference.

Checked over the intake clamps/piping/cooler last night, all ok and no visible faults, sorta hard to check for leaks under boost (ie. soapy water) without the dyno. Not to say the cooler isn't leaking or somewhere else though. R&R is still a possibility too.

We have a MODIS at work, hooked it up and took the car for a drive. AFM appears to be ranging normally, hit a maximum of 4.94 volts, WOT, 2nd gear, ~6950rpm. Voltage goes up consistently with TPS/RPM but car still feels the same. Also reset the TPS before-hand due to it having a base setting of .30 volts.

@ WYSTKY. In the top end, i'm not actually running the full 7 psi, the mechanical gauge fluctuates after 5000rpm between 7psi and 5psi, so it's making the maximum figure on ~5psi, combined with as much as 8.5:1 AFR, not bad power......

I'm going to keep checking the basics, it's also due for a service so will get onto that between now and the next run. Still want to check the fuel pressure in case of a bad reg or simply too much pressure.

Edited August 25, 2011 by blk94r33

[blk94r33]

So far so good.

Removed the cooler, bathed it-ok. Re-fitted, re-checked the clamps and hoses including the BOV return, AAC, turbo outlet etc. etc.. Took off the BOV, still has resistance and appears OK. Ran start-ya-bastard around the intake manifold, plenum and throttle body, injectors, turbo etc.-no change (again, could change under boost) and checked all the bolts/nuts. But otherwise all appears fine in terms of air leaks.

Fuel pressure is normal, 45psi at idle, goes up to 55-60psi when revved-appears to be working. Will re-drive the car tomorrow and see if anything feels different, but otherwise going to look at some form of engine management or even an SAFC at this stage and work from there.

[WYTSKY]

Its a mass air flow meter, pressure has no effect. Also both N/A and Turbo AFM's only measure atmospheric pressure as they are placed before the turbo (aka out of boost), but putting them in boost makes no difference as 500CFM @ +14psi travelling at x speed is the same as 500CFM @ ATMO travelling at 2xX speed (for example).

Its all about the voltage range (which is the same between the 2 items), if his AFM is healthy it shouldn't make any difference. It still wouldn't hurt to swap it with another though as it still could be the cause, it could be because the AFM was already faulty and miss-reading, and the increased airflow is throwing it out more and more.

That said, my money is definitely on some sort of boost leak or R&R issue.

I once had a similar issue with an RB30e+t, couldn't find the leak so I moved the AFM into boost as close to the throttle body as possible and it fixed the symptoms (though still slightly down on power as the turbo had to work twice as hard to produce the same boost) at least until I could find the cause.

What BOV are you using? Plumb back? I've known some ATMO's to leak boost and cause similar issues.

lol, ur bloody right, long day yesterday, I keep forgetting because I have relocated mine in the intercooler piping so it does get +ve pressure, but factory location (infront of turbo) wont do that.

In terms of the na afm maxing out, is it not possible the n/a one may not be able to read as much air at a particular voltage compared to gtst? - eg the n/a will give a 4.2 volts at X amount of air while the gtst one will read 3.2?

+1 for boost leak or afm issues.

[blk94r33]

lol, ur bloody right, long day yesterday, I keep forgetting because I have relocated mine in the intercooler piping so it does get +ve pressure, but factory location (infront of turbo) wont do that.

In terms of the na afm maxing out, is it not possible the n/a one may not be able to read as much air at a particular voltage compared to gtst? - eg the n/a will give a 4.2 volts at X amount of air while the gtst one will read 3.2?

+1 for boost leak or afm issues.

Not finding any air leaks yet, but as I said might need to get the car on boost on the dyno and re-check.

Not %100 about the AFM? As I said, it hit ~4.95 volts at near max revs, stock (for the ECU) boost, and WOT, so I suppose the GTST AFM would range up to 5 volts, and the N/A one only uses say 2/3's of that voltage? I imagine if the NA AFM was different it would "top out" at a much lower air flow than 7psi?

Only other thing I could think of would be a dodgey vac/pressure gauge reading low, and i'm in-fact running more air and hitting R&R....