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not too great on power gains but sound fantastic and lok really good in the engine bay! Still, Id probably go for a Hillpower one if I could choose again.

I tried to modify the standard box but kept stalling, too much air i think. Would this mean if i added a viper or hillpower i would need the ECU remapped?
  Nissan R35 GT-R

Two facts about induction jits:

They do not give more power. They are more likely to loose it, but something like the Viper will not loose horsepower as it is very nicely shielded and may improve throttle response marginally.
You do NOT need a re-map after fitting an induction kit. If the car is getting more air, the ECU simply moves to a higher load site and adds the proportional amount of fuel.
Dust: If you kept stalling then you probably did something wrong. You can drive a car without any filter at all.
  Lionel Richie

Frosty, you DO need a re-map if your fitting a viper, cos it makes the 172 run dangerously lean at WOT. BenR will explain it better, from his experience 172s are very sensitive to intake changes.

The ECU can adjust to a certain point, but it cant work miricales!!!!
  ICE'dberg MK2 172

I understand that the lambda sensor in the exhaust reads the emissions and the ecu then alters the fueling to compensate for the extra volume of air....but only up til 3K revs. After that the ecu relys on static maps already programmed hence the remap.

Que BenR...........

After I fitted mine and the K-tec, it rollered at 158bhp!!!! fueling was way out...20mpg!!! remap not only sorted the fueling and Co2 but it now has 180bhp!

I think i have started something here!!!

I think i will leave the induction kit and maybe go for the Dastek chip and maybe the LAD conversion when the CCC mag reviews it.

Cheers guys.:)
  ICE'dberg MK2 172

172 man

The Lambda sensor is in the cat and its remapped by Superchips.


How about throttle bodies....mmmmmm! better response and about the 200bhp mark.

you cannot remap the lambda sensor its just a sensor.!!!!!

you can only put a new map into a programmable ecu.

And i do not rate super chips at all.

the only way to map an ecu is on rollers and that will not work very well because there is no forced induction.

I cannot see a viper making the 172 run lean as it has a cold air feed in the standard box any way.

Did they do a roll down test as rollers can only do bhp at the wheels, how did you work out the 180 bhp figure ???
  ICE'dberg MK2 172

Quote: Originally posted by chris172 on 14 March 2003

172 man

The Lambda sensor is in the cat and its remapped by Superchips.

Sorry for not being clear but I know you cannot remap the lambda sensor I was answering his 2 questions.

my, were goin over points we have gone over a million times.

The 172 runs a set reference table at WOT. There are no live adjustments.....hence the danger of it running lean or rich, but again inlet charge temp does matter.

I didnt rate superchips until i worked with them, they are very professional and IF you can get them to do what you want, they do it well.

The lambda is not remapped......the ecu is....but it doesnt have to be a mappable one, the RENIX system was not desiened to be remapped, its gota few bits you have to get by, but you can one in.

All in all, it helps.

whys everyone chatting about remapping lamabda - pun sensors grrrr. What the hells a WOT

did you miss the SIT part?

Chris 172 i am hoping to really develop the motor and take it in stages little at a time, I want to get over the 200bhp with a series of mods and the chip and the head work. I know it is a bit expensive through LAD but from past experience with dodgy back alley garages quoting big figures and then my engine blowing up i would rather spend the extra and get a decent job. Once i have the smaller mods in place i will start to think about the TBs :)

throttle bodies will give you straightoff larger increase than playing with the head and supposed cam timing like LAD do. The std throttle body size is tiny and wont really allkow you to comfortably push 200bhp.

A set of quad items helped us to 215BHP on std cams and head.
  Nissan R35 GT-R

My point is that the car has an airflow sensor. This sends a signal to the ECU to tell it how much air is being introduced, and the ECU in turn looks up the relevant load site at the current RPM and applies the fuel and ignition setting. Simple!

If the car is getting more air, the ECU will simply look to the relevant air-intake point, and apply the correct fuel settings.

The image below is a map for a Lotus Elise. You can see that the engine speed sites go across the screen and the load (airflow) sites go down the page. In the image the airflow is very small (as throttle is fully closed) and the engine is at idle.

If the car was getting loads of air, but still at 1000rpm, the load site position would be down somewhere like 10 or 12.

I hope you can now all see how the ECU is compatible with an induction kit that flows more air. Any questions?

Its nto quite as simple as that, especially on non standalone management.

But i am far too drunk to get into it right now.

But the Dave walker book is quite good, if lacking tech.
  Nissan R35 GT-R

Its a very good introduction to the topic.

Once I had read the book everything made sence and all the further reading I have done on the subject is so much more comprehendable now. Id recommend it. :)
  Nissan R35 GT-R

Oh and when you sober up ;), could you explain "the difference between theory and practice" with regards to the running lean business and what I have stated as my knowledge on engine management goes only a little further than that book does.

Im always interested to learn more.

Regards - Laurence.

simply put, the RENIX system has a ref table, not like your ref sites, which it uses from x rpm to the limiter....simple....

with no provision for air temp you can run lean as sealed IKs typically lower inlet air temps by about 50% as its designed to runa t about 80-90 deg F.