CAF length? Engine gurus please help.

[LegoHead]

I get a flat spot from 5500 to 6500 (146 atw, not too shabby.), which i think is down to me not connecting the caf to the viper induction kit.

How do you calculate the length of the inlet to get the most out of the engine?

 

[len_beach]

It's probably more to do with the fact that you have a Viper

 

[Tim]

mines about a meter dave from the front lower grill .

got it from tweek's it's the brake ducting stuff i think .

 

[LegoHead]

It's probably more to do with the fact that you have a Viper

I dont think so. I think its more to do with where the resonant frequency of my airbox and feed is.

 

[BenR]

lol, sadly to 'calculate' any effective answer for you would see months of number crunching and software analysis before anybody could comment on what would be the best direction.......then you would have to trail and error the test.

tuned lengths on plenum setups are INCREDIBLY hard to calculate and almost everybody in the racing world uses trial and error as its faster than 'calculating'.

 

[makavelli]

dave what mods is your car running at the mo?

would a good remap not sort out any flat spots?

 

[mini-valver]

He's running an SMT6 IIRC!

 

[LegoHead]

lol, sadly to 'calculate' any effective answer for you would see months of number crunching and software analysis before anybody could comment on what would be the best direction.......then you would have to trail and error the test.

tuned lengths on plenum setups are INCREDIBLY hard to calculate and almost everybody in the racing world uses trial and error as its faster than 'calculating'.

Just what i thought. I was wondering if you know a way of me seeing gains/losses at home without having to dyno the car or thrash it on tons of 0-60 runs?

Any equipment I can use? I have access to a load of automotive tools and test equipment at work.

Will start initially by temperature testing the air inlet as thermal testing is currently my speciality. But eventually want to get a well tuned length.

 

[LegoHead]

dave what mods is your car running at the mo?

would a good remap not sort out any flat spots?

I have had my smt6 for a while might need remapping, but I think concentrating on the air intake first would be my best bet. The car is running rich at the moment.

 

[makavelli]

dave what mods is your car running at the mo?

would a good remap not sort out any flat spots?

I have had my smt6 for a while might need remapping, but I think concentrating on the air intake first would be my best bet. The car is running rich at the moment.

ahh i see

while your at it you could have a look at the best place to source the air from as well ie, lower grill, fog light, passenger wheel arch :approve:

 

[stan*]

there are easy enough calcs which include valve open period and speed of sound, to obtain a length for a specific pulse return at a specific rpm...they however realy on assumptions such as constant temps , and so pulse propogation. they dont however include harmonics affected by plenum enclosure.

sounds like its trial and error through the bum dyno"!

 

[BenR]

I would of thought some sort of G meter test using rolling starts only.........possibly something with logging and download facility to overlay the results in graphical form.

 

[LegoHead]

Do you mean one of those gtech meters Ben? I dont think they are very good, as the data they give is inconsistent.

I was wondering is the rpm output signal good enough for measuring acceleration? For comparitive measurements.

 

[BenR]

only if you have a timescale and consistant gradient, running conditions.

Technically the G meters are pretty simple and infallable in their true sense, all depends on setup and repeatability, which is why i said rolling and no standing starts.

 

[ja.jack]

Tell them to forget about cafs and vipers Ben, that stuff will be history when your new induction system comes on stream.

 

[GordonD]

http://www.digimoto.com/

They claim their software can produce power and torque curves based on knowing the mass of the vehicle, monitoring what they can read through the OBD-II port, and timing how long acceleration takes.

Actual power and torque curves would be more useful than what a G-meter produces.

The question is whether their product would work on a Clio Sport's OBD-II port. Someone posted some time back saying they'd bought from them and the product had worked on another Renault.