HFS4 on 996tt

[zx9rmania]

Hi all,

car is 996tt with gt30s turbos, upgrade fuel system 80cc injectors and trying to run in the end about 1.6 bar or more.

Car is running a bit rich even without meth, lambda set point is 0.8 and actual values are 0.78-0.8 most of the time

i tried with W60/M40 on defaul mapping (IDC) and after that W45/M55 on a custom mapping (MPS) and the same result, i see lambda going down to 0.73, engine load gets very high and engine is coughing

I am told i need to start injecting by 7 psi and full at 15 psi, any thoughts ?

thanks a lot

Fadi

[zx9rmania]

Richard, can you help me please ? I used a basic kit instead of HFS4 and it works...
Isnt this kit supposed to be plug and play for basic users anyway?

[Richard L]

Based on your is post, running rich is not good especially you injection water/meth on top. Reduce your fuel flow until you are running ~11.8 AFR

[zx9rmania]

i used same aquamist pump, meth lines, injectors 2x1.2mm !!! and replaced your controller with a basic on/off boost switch at 10 psi reading boot from the intake and linked to the pump... car is running OK, i see much much better timing, better than with ms109 !!, perfect afr-not running rich anymore, but no iat drop, just slower increase of iat.... but i am able to run much more boost, so the problem is from the controller... are you sure the wiring diagram is correct ?

[Richard L]

if you are running 2x 1.2mm jets and see no IAT temperature drop but much better timing, there must be something wrong with the temperature sensors. Send a picture of the jet installation.

Replacing the controller with a boost switch makes the car runs better, so there are really no problem to solve.

[zx9rmania]

i bought the most advanced controller from aquamist, not a basic boost switch like 20 years ago, this is the problem


used both places to inject, see pics attached

[Richard L]

The HFS4 can be triggered by boost and set to on/off mode. You have just wasted your money on a mechanical pressure switch?

[zx9rmania]

I tried that just to make sure the system works, i had already that boost switch.

Seems i have found the biggest problem :

I just untightened the bypass screw on the pump and now IAT is dropping 10-15C, sometimes even bellow ambient temps, i think this was the problem... now i have to fine tune it, still getting rich but car is not bogging like before, maybe a bit less meth and maybe a bit later will do the job.

I would inject mostly by boost (P/I-R almost all the way to the left) but in the IDC and PWM mode, if this will be difficult i will switch to MPS/PWM and the last chance will be MPS/SSG and add later on all failsafes, i will still run with DFS on for now

[zx9rmania]

if i switch to mps the amber led is always on and system is injecting all the time,any ideas ?

i tried different thres, gain, p/i-r setttings but no luck.

[Richard L]

There is something very wrong on this.

Can you measure the voltage at test point 17 relative to ground (bottom left of the test points)

[zx9rmania]

now is ok, was a wrong wire....like 1.x-2V at idle.. As i thought i am injecting too much meth I put just one 0.5 injector and car still boggs when kicking in... it can not be too much meth i supose.... we were running a very low mix like 30meth/70water. AFRs are going like 10.7, i am targeting and reaching 11.8 AFR on pump only. With 2x1.2mm we measured up to 7-800cc/min flow, injectors are 80cc and IDC at 1.5bar is like 70% peaking 75% sometimes

My install was also validated by another user fo yours cipsony who owns a very nice and fast audi ttrs, thank you Ciprian !


A 0.5 injector for this engine could do so much harm ? Besides retuning ??, i dont know what to do, i am lost......

[Richard L]

I am very confused with your approach. Remember you insisted on using two 1.2mm jets? Now using one 0.5mm, you get bogging. What is going on here?

[zx9rmania]

All I know is that Aquamist seems to work fine now, temporarly i have installed a secondary meth kit to double check WMI and my AFRs and everything with both of them, and in the engine keeping just Aquamist :) They dont run in parallel, just one enabled at one time. I was reducing the quantitiy of meth injected by reducing the size and number of injectors, that's why i ended with a single 0.5 now. IAT is dropping ok

With both systems, i saw HIGH ENGINE LOADS and 0.73 lambda with every combination of injectors (big, small, dual, single) and every combination of meth mix (30%-100%)

I dont know what is causing this, but if i will find out the answer i will know what to do next.

I target 0.8Afr (11.76) and this is also what i get on pump, on meth i target also 11.76 and i go down to 10.7 and high engine loads (240 instead of 170), any ideas what is the reason for this ?

[zx9rmania]

I meant Aquamist is working fine as i think my problems arent anymore related to the meth system, maybe the tune or something else

[Richard L]

It appeared you have some misfire fuel to weak spark (carob build up). or over-sized gap. It the fuel are not ignited properly, you get get excessive amount of oxygen, This could be the cause of low lambda value.

Get a new set of spark plugs and start again.