Tuning ... You’re Only As Good As Your Tools

[Headsex]

2008-Feb-11 10pm..

As promised.. I"m going to go a little in depth with the next tune I did.

Subject: BA XR6 Turbo, 4 Speed automatic

Mods: Atomic engine + oil pump drive + valve springs, 60lb injectors, Some custom intercooler with a custom pipe from under battery pipe to plenum, Pod filter, 3500Rpm Stall convertor.

Wow I thought. A built engine. But I didnt get too excited. I knew there was a lot of things missing.

First dyno run, 250rwkw. Looking at the datalogging explains why. There was 2 possible reasons. The stall convertor was only flashing at 5000rpm on the dyno.. Imagine taking off and your revs bouncing straight to 5000rpm and sit there whilst your speedo was catching up. This would I estimate be stealing at least 30rwkw. Mainly because the engine was not driving the wheels, it was using the hydralics of the torque convertor to bring the driveline upto speed, this brings torque up, but power is lost.

The second reason is I could only get 13psi boost. Because the car still had the standard 3psi actuator in it, it did not have the spring presure to hold the wastegate shut to allow boost to rise.

So thinking about things a littlebit, I also assumed the compression ratio of this engine would be lower than standard.. so I added another 4 degree's timing in after 2 further runs. bringing power from 250rwkw to 280rwkw. If there was a standard stall convertor in the car, I believe this would have read anywhere between 300rwkw and 310rwkw based on the boost and timing it was seeing.

So that's all she wrote.. Lets look into why it wouldnt make any more.. Remember, its a built engine, big rods, big pistons big everything..

1) Wastegate Actuator was standard, they are rated at approx 3psi, and when the PI controller was commanding duty cycle of 1, all it saw was 13psi high in the scale..

To fix this, turbo would come off, and you would replace the actuator with a 12psi actuator. Whilst the turbos off, you would also port the exhaust wastegate, and fit a bigger swing valve to combat any possible overboosting problems when the other mods below are done.

2) Fuel pump was standard.. We done a number of runs, and the more aggressive boost come on, it would sometimes pop the relief valve on the fuel pump and run lean. So I made the boost come in as soft as I could (remembering the stupidly large stall convertor), and adjusted the injector high slope to combat that problem a littlebit.

Suitable options here would be a Intank Walbro from the GSS340 family (I like the gss340 as it has a nice big fat intake). Or even a Process West Surge tank and Bosch 044 pump.

3) intercooler wasnt upto the task. I am unsure on what kit this was, it looked like a bolt in replacement, but given the AIR temps we were seeing.. although, sitting at 5000rpm for half the run wouldnt have helped either, the temps were rising fast.

Given a built motor, I would almost be advising the customer to put some sort of plenum kit on it to cut down the cooler plumbing and give a nice good flowing system.

4) Exhaust was standard.. In my experiance, the most I could push out of my car was 315-320rwkw.. That changed when I changed my exhaust.

So, Given all these are sorted, A retune will give him a very powerful car.. somewhere in the high 300's

Ohh, and in conclusion.. 5000rpm stall convert is useless on the street. Mario is going to mention that the convertor is not 3500rpm as sold to him, but rather flashing at 5000rpm.. I really hope next time I see this car the stall convertor problem is going to be sorted. or at least a standard convertor fitted to the car so I can tune it properly.. Cos really all we were doing was mapping 4800rpm to 6500rpm, the convertor wouldnt hold the revs any lower.

[Headsex]

Nice write up Danny. Sounds like you are progressing this tuning hobby to perhaps a real job/career?

So you are now advancing from car park & street tunes to dyno tunes?

Are you using the SCT Flasher or Snipper these days?

You need to see the Dyno room setup @ Tunehouse. Let me know when you are next in Sydney and I will take you in for a tour.

The real job / career aspect is getting a good think over.. the question is.. Do I really wanna take the pay cut?

I've always done tunes on the dyno.. that's how I know what sort of numbers to put in when I setup the tunes on the street. I love setting up the boost on the street as its time consuming to do.

Depending on the customer, im using Capas software, or if they prefer a tune without a box, I use Sniper (I dont own it. I borrow someone else's).. HP Tuners isnt far around the corner either, and given autotechnique is vcmsuite, that's what I'd be using in the near future..

I really do need to come upto sydney.. Need to see what strip clubs are like in comparison...

BSW1 ?

A lot of good info on various things there...

Dyno's, tuning and intercoolers.

The cell is my favourite part about it all

The best benefit about it all... I dont go home like I was swimming in petrol..

Champion, I appreciate the explanation. Not having the software myself, it's very hard to understand how the calibrations interact and there is very little information available. However you are helping in a bit way, cheers! Lucky I got a big cooler etc on it's way to perth, anyone want to buy my wogcooler lol.

These cars really do benefit by a big cooler that works.. and remember, just cos its big, doesnt mean it works. Im sure the intercooler testing thread (when it goes ahead) is going to amaze a few people..

Does this mean your tunes will be cheaper?

no.. more expensive

Danny I guess this is why Nizpro use a thermostatically controlled water to air intercooler on their engine dyno when doing calabrations for these and other engines.This is so they can map the engine at a constant air temp and once fiished go back and check all different air temps and the amount of ignition timing correction that is needed. I believe they also can do this for both the water and oil temp as well. I doubt you will see this on a chassis dyno but Mario's sound very good.

that's right, On their engine dyno, they can sit the engine tempreture, and intake tempreture (as its a water to air cooler) at a very stable setting. Im sure it would be adjustable, but that is the ultimate way of tuning engines.

Its not practical however, to pull a engine out of a car, and put it on a engine dyno, tune it, and put it back in as many would agree.. Imagine how much tunes would cost then!!

BUT this is a ideal tool for research and development of modifications such as cam and turbo changes.

[instro]

I hope you keep the write-ups coming, their an interesting read.

[rob82]

1) Wastegate Actuator was standard, they are rated at approx 3psi, and when the PI controller was commanding duty cycle of 1, all it saw was 13psi high in the scale..

To fix this, turbo would come off, and you would replace the actuator with a 12psi actuator. Whilst the turbos off, you would also port the exhaust wastegate, and fit a bigger swing valve to combat any possible overboosting problems when the other mods below are done.

Chances are either your exhuast is not good enough or you've got a big pressure drop accross the intercooler. that's why you couldn't get the boost in, a good trick is to measure the pressure pre intercooler - if the setup is correct then you should only get around 2psi drop at around 300rwkw. On the correct setup there is no reason you cant deliver a flat 15psi of boost pressure with the standard 4psi actuator.

[senna_T]

I can get a 15psi spike but it only holds at 13psi, stock plenum and dump, gutted cat, dual 2.5" exhaust = 340rwkw

[Headsex]

Chances are either your exhuast is not good enough or you've got a big pressure drop accross the intercooler. that's why you couldn't get the boost in, a good trick is to measure the pressure pre intercooler - if the setup is correct then you should only get around 2psi drop at around 300rwkw. On the correct setup there is no reason you cant deliver a flat 15psi of boost pressure with the standard 4psi actuator.

that's right. But the guys car still had standard exhaust, and some bolt in replacement intercooler as I mentioned eariler. I'm sure if the cat was gutted, 15psi would have been achevable.

The upgrade options his been given were:

1) better cooler.. the likes of a process west stage 2 or a nizpro stage 1 for instance

2) full exhaust

3) fuel pump

4) actuator / wastegate port

but I personally like porting the wastegate, and fitting the actuator eariler on.. so boost is more reliable

Given his got a built atomic motor.. Both intercooler and exhaust need to be addressed.. as well as wastegate port and actuator so we can dial in the likes of 18-20 psi..

Edited 13/02/08 12:25 PM by Headsex

[Headsex]

I can get a 15psi spike but it only holds at 13psi, stock plenum and dump, gutted cat, dual 2.5" exhaust = 340rwkw

From experiance, you can only make 310-315 rwkw with 13psi high in the rpm.. And that's with a good intake and good exhaust.

I'd like to see a Dyno graph in shootout mode with power and boost logged to make sure the dyno corrections have not be altered.

[RAP1D]

He's got my intake and 3 inch IC piping, so similar deal as my car with same sort of boost response... this car moves very well, 340 is on the money for these same mods.

Boost response may compare with the black F6?

[senna_T]

you got in before me chris! Danny, I'll have a look for the graph, I've posted it here after the tune was done - gimme a minute!

[senna_T]

here's the graph click here