Reason for Richness

smidge

smidge

Small Car Enthusiast
Site Supporter
okay fellas so i've changed the turbo, checked my IC piping twice over, fixed an exhaust leak on the dump and now ready to fix my longest running problem

the ST running bulk rich on the turbo!

i've got a wideband permanently installed, the power seems okay on the supercharger, mixtures hover around 12.4

as soon as we're on the turbo, the mixures shoot up to 10.5 or even richer

anyone know why this might be?



Mods:
2.5inch exhaust cat back (factory dump)
FMIC
Turbo boost set to 15psi using a bleed valve
cut down intake, silicone joiners straight off turbo to a 3inch pipe with all required vac fittings then onto a blitz pod filter
 
Seal the pipe that goes into the TB and then pressurise the whole system and see if you get any leaks as a starting point.
 
Cool will do, I've got a handy boost leak tester that uses a car tyre type fitting, so i can pump air into it while keeping an eye on the gauge

i'm not expecting it to actually hold pressure, some will leak out, but i'm listening for obvious gasket leaks right?

soapy water in a spray bottle a good idea too...?
 
If you have got it right it will hold pressure!! (on a normal car anyway)
 
Yes, however they shouldn't go really rich all of a sudden for no reason 10x:1 is far too rich for any Jap engine.
 
ah i see it took me a bit of pondering you figure out what you mean

you mean block the pipe the air filter is attatched to, and block the throttle body and test that everything in front of the throttle butterfly holds pressure

cause compressed air into the actual engine is just going to leak past valves etc, right?
 
Have you had your car mapped since that first one you had done??

Considering your induction wasn't in very good shape at the time it could be part of your prob. Maybe get it on a dyno now that you have your induction fixed up and make sure your fueling is right. Just a thought.
 
i'm convinced its leaking, i expect it to run a little rich but the wideband just says RICH when i get into any serious amount of boost

i will have it on the dyno as soon as i've eliminated any possible leaks
 
Definitely sounds like a leak although if it was really bad id expect you to hit the airflow limit... (kind of boost cut)
 
smidge said:
i'm convinced its leaking, i expect it to run a little rich but the wideband just says RICH when i get into any serious amount of boost

i will have it on the dyno as soon as i've eliminated any possible leaks
Click to expand...

did you end up changing anything here? I'm not familiar with the ST ECU, but many of the other nissan ecus from the late 80s act the same - bulk rich when you turn the boost up a little (to protect the motor once it goes outside it's stock parameters)

I didn't really feel or hear any boost leak, it seems to be running OK.
 
didnt change anything except one of the silicone intercooler joiners which wasn't holding pressure properly, boost leak tester made it whistle a bit and once the new one was on it was all good, scored a few points back on the wideband and smoothed out the idle

you're probably right with the nissan bulk rich up top issue, its done that most of the time i've owned it, a remap is really what it needs
 
thanks Baz. Are you running the stock turbo, and what boost are you running? I guess the head gasket will be the limiting factor...(assuming the stock turbo is steel wheeled, it can't be ceramic and that laggy!)
 
Duncan said:
thanks Baz. Are you running the stock turbo, and what boost are you running? I guess the head gasket will be the limiting factor...(assuming the stock turbo is steel wheeled, it can't be ceramic and that laggy!)
Click to expand...

No its a HT10/T2 hybrid I got from Ed built by turbotechnics in the UK. Running 1.2bar with a blitz electronic boost controller on track with an FMIC ,greddy Emanage controlling fueling and ignition, everything else is stock engine wise has'nt let me down the last 2 and half years.
Uprated parts are Nismo paddle clutch ,Spax coilovers ,15" wheels with Toyo R888's, Result is 120hp at the wheels roughly, 151.8 at the fly if your looking for bragging rights lol and a great track car, cornering speeds are incredible when you compare it to alot of the big cars

Here's a few vids man to inspire ya

(Y)

Baz

http://s77.photobucket.com/albums/j...iew&current=MarchSTagainsttheBOBCATLegnum.flv

http://s77.photobucket.com/albums/j42/crazyep82/?action=view&current=Dtdtrackday.flv
 
Snikty said:
Is the T2 part the compressor or turbine??

I'm guessing compressor as I don't recall you ever mentioning a moddified manifold.
Click to expand...
Your dead right its the compressor side but the turbine wheel is slightly larger aswell but uses a modified ht10 turbine housing
 
haha good work, great looking track too but man there is some traffic! And wtf is the rubbing noise in the second video?

the T2 bit I understand...but what is an HT10...I've got sfa knowledge of turbos this small....the gtr comes with 2xT28 and the big cars run T3/T4 hybrids :eek: Might just see if Ed feels like posting another one out here, I've got one for exchange with farked seals that Marty took off it.
 
I can do another but its NOT cheap. You would be looking at around £1K GBP.

Had I done that now I would simply weld a flange on to the existing manifold and use a stock T2 or T25 :)
 
Duncan said:
haha good work, great looking track too but man there is some traffic! And wtf is the rubbing noise in the second video?

the T2 bit I understand...but what is an HT10...I've got sfa knowledge of turbos this small....the gtr comes with 2xT28 and the big cars run T3/T4 hybrids :eek: Might just see if Ed feels like posting another one out here, I've got one for exchange with farked seals that Marty took off it.
Click to expand...

HT10 is the standard hitatchi turbo on the st

Have the reciept here Ed from turbotechnics £940
 
There would be places over here that could do that sort of turbo build for you. It would be extremely expensive to get it done in GBP plus shipping, due to the state of the aussie dollar. I think you'd be looking at $1000-$1200 to get it done locally by someone reputable. 1000 pounds is about $1800.
 
Snikty said:
There would be places over here that could do that sort of turbo build for you. It would be extremely expensive to get it done in GBP plus shipping, due to the state of the aussie dollar. I think you'd be looking at $1000-$1200 to get it done locally by someone reputable. 1000 pounds is about $1800.
Click to expand...

Not bad(Y) here in Ireland I don't think we've any facilities
 
yeah I'll probably talk to a local place, I've used precision turbs in the past. not sure if they know too much about turbs this small.

I'll look into the gtr t28 size, 2 are used on 2.6l for 220kw on the gtr, so 1 should be right for 110kw on 1l (and I've got heaps of them around). might be laggy but hey thats what the SC is for, right?

sorry for all the OT....I will post up a seperate thread when I get going....no rush yet
 
Duncan said:
yeah I'll probably talk to a local place, I've used precision turbs in the past. not sure if they know too much about turbs this small.
Click to expand...

Try asking on the aussie pulsar forums. If you wanted to use something like a T25 you could probably use something like what many of the ET owners use as they often set them up for running similar boost levels and are only a 1.5
 
Ed has spoken twice...and it looks like he is a man of few words. t25 or t2 it is.

Baz what rpm does your turbo make 1.2 bar, and have you done any porting, cam orchanged the dump pipe?
 
I put a GT28R on mine. Its too big for the 0.9L engine. Doesn't really spool until about 5K rpm.
 
Duncan said:
Ed has spoken twice...and it looks like he is a man of few words. t25 or t2 it is.

Baz what rpm does your turbo make 1.2 bar, and have you done any porting, cam orchanged the dump pipe?
Click to expand...
The down pipe has the cat removed, no porting , no cam change. The turbo gives 1.2bar straight away when the s/c knocks off but on track if your out of s/c range (4500rpm -7000rpm) and off throttle the turbo can take a bit longer to spool up than the ht10 did coming out of a corner
 
Baz said:
The down pipe has the cat removed, no porting , no cam change. The turbo gives 1.2bar straight away when the s/c knocks off but on track if your out of s/c range (4500rpm -7000rpm) and off throttle the turbo can take a bit longer to spool up than the ht10 did coming out of a corner
Click to expand...

More driving with both feet imo :p
 
Bombardier said:
The reason for the richness then perhaps?
Click to expand...
Shouldnt be.

If a car really is running rich, then that can only be because of a couple of reasons. One, there is a leak somewhere after the turbo but before the inlet manifold or two water temp sensor is not reading correctly. It can also be a dirty faulty air flow meter but thats rare.

Ed
 

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