Next Upgrade Help Please

[borgan]

I feel that the ECU route is the way to go. My reservations on the Blitz ECU is that it's been mapped for the Jap market. Is it mapped to run on 102 RON fuel? If so,expect detonation quite soon after purchase as the fuel will be mapped to run leaner & 97/98 RON fuel doesn't have the same cooling characteristics as 102 RON fuel. What mods did the vehicle it was mapped on have? If standard then you're not going to get the most from your existing mods, you're not going to get the full benefit of an exhaust or induction upgrade. I think that it's better to get an ECU mapped to your own car, with your mods & with the fuel you're most likely to use. The most important person if you're going for this upgrade is the tuner. A good tuner will give you excellent results whereas a poor one will leave you wishing you hadn't bothered.

[pjjohnson]

Why not try the Unichip, it will control boost and fuelling for you, about £650 fitted and mapped for your car on a rolling road.

Regards boost controllers, I've had a HKS EVC4 for yonks and it works a treat. Can't say what they are like to fit, but they are easy to set up and they hold boost well without spikes. At £200 its would be bargain.

[enigma]

I am not going to ask how you determine that there are no spikes.........doh!

[pjjohnson]

Would have been a good question, why didn't you ask it ?

The HKS EVC has a safety cut out that triggers at a preset boost limit, and EVC 4 has a boost gauge which you can look at and see what the boost is running at all the time but mostly becuase the 'expert' tuners that have done their thing with the car tell me that thats its not spiking.

What is a spike anyway ?

[Nick VR4]

Originally posted by pjjohnson


What is a spike anyway ?

On a pull-through intake, when the turbo is boosting and the throttle is suddnely shut INSERT INTO post VALUES (while shifting, for instance); a huge vacuum is generated between the engine and the throttle body, and the turbo is spinning in a low-pressure environment. This is good because then there is less air friction to slow the turbine, and so there will be less lag when the throttle is opened again. However, it takes a moment for the compressor turbine to get the air flowing fast again, since the air was at a dead stop. On the blow-through intake, when the throttle is closed, a huge pressure spike is produced between the turbo and the throttle body, because the turbo is blowing against a closed throttle plate. This slows the turbo down very quickly and there is a lot of lag when the throttle is opened again. The pressure spike is also hard on the turbo and intake hoses. To remedy this, the production blow-through setup features a blow-off valve INSERT INTO post VALUES (BOV) on the output hose of the turbo. This is a large, vacuum actuated valve that opens when there is vacuum in the intake manifold INSERT INTO post VALUES (closed-throttle). This valve vents off the pressure spike, avoiding the quick spool-down of the turbo and potentially damaging pressure spikes. Although the turbo still slows down more than the pull-through setup does during the time that the throttle is shut, pressure is brought back up just as quickly because the air is still moving. When the throttle plate is opened again, the BOV immediately shuts and the air flow is directed back into the engine. Also, the 1988 and later Turbo I engines had a smaller turbo, which further reduced the lag. So all in all, the two setups are about even in performance

[chris g]

But even if you choose an upgraded ECU such as Blitz surely the problem of fuel starvation can persist?

The upgraded ECU may alter boost, timing and fuel maps but if fuel pump and ? injectors cannot supply the required amount of fuel as and when the engine demands it then you could be in serious trouble?

Upgraded ECU seems a one-stop solution to increasing power but then requires other mods/kit to use the benefits of the ECU?

[enigma]

My understanding of spiking is different to Nicks...............

A boost spike exists when you stamp on the throttle, the turbos spin up quickly generating huge pressure, the sensor detects this high pressure and begins to adjust the solenoid valve. This in conjunction with the finite amount of time it takes the system to respond leads to a spike.......I could go back to control theory here INSERT INTO post VALUES (B.Eng in Control Engineering) but suffice to say the system will have a response somewhere between no overshoot and slow spool up, and big overshoot and fast spool up. I am in favour of fastish boost build up and a medium amount of overboost. This overboost occurs for fractions of a second and I therefore consider it not to be a problem. I will try and capture this on my boost controller to show you what I mean.....either that or I will draw a pretty diagram!

As for the ECU or Other mods question, I guess it all depends what you want. I would be wary of the ECU as there is potential for a bad tuner to get their hands on your car, also it is not easy to change the settings......without getting back to a rolling road. It is for this reason I got the mods I did in the order I did. If I want more power in the future the ECU is my next option........but this would have to be followed closely by new turbos, injectors, fuel pump, forged pistons etc etc. For this reason I am not planning on doing it, I will stick to 370ish BHP and a 100 shot of NOS every once in a blue moon.......If I want to go fast I will strap myself in to my Skoda!

[borgan]

If you're getting a GOOD tuner to map the ECU of your choice then they are going to ensure that you're getting a safe amount of fuel. The VR4 shouldn't suffer from fuel starvation with the HP increases most of us are trying to achieve. If the VR4 injectors are 390cc then, if what i've taken on board in the past is right, they should be O.k upto 468 HP INSERT INTO post VALUES (injector flow rate divided by 5 multipiled by the No. of cylinders); although it would be preferable to change up once past 400 HP. This adds weight to the argument that factory ECU's are mapped on the rich side to avoid detontation. That's why increasing the boost without altering fuelling is safe to a certain point INSERT INTO post VALUES (around 14psi it seems with the VR4).

If I was adding a boost controller I would still prefer a tuner to set it up for me. I imagine it would take me ages to set up correctly. If I was lucky I wouldn't blow up my engine. I'd probably end up having less power & turning the unit off. Dave, however, has the skills & knowledge to get the power he wants by himself. 270 - 280 at the wheels is proof. He revels in the fact that he's achieved all these gains himself INSERT INTO post VALUES (at very low cost). That's how he get his kicks. The majority of us, with the same kit INSERT INTO post VALUES (metal tubing, a baked bean can, an apexi boost controller & £30 air filter) wouldn't make those gains. If he had access to a mappable ECU with the s/ware to adjust the maps himself he'd have a monster of a car.

[Brind]

ECU upgrade could possibly be safer than fiddling with manual boost settings even electronic settings.
But spending £900 to gain an extra possible 60bhp from the stock turbos isn't my kinda of spendin'.
With an upgraded ECU you are stuck with the power you gain and consequently effects fuel economy in a bad way.
Changing the boost settings yourself could be just a quick buzz but when you want to revert back to better fuel economy you simply turn it off.

Obviously this is just my opinion.

[enigma]

I totally agree with both Mark and borgan!

Firstly Mark I run 0.7 bar most of the time, the APEXi boost controller allows 2 settings, so if I pull up at the lights next to something interesting I leave it as is and waste it! If I pull up against something really interesting I change to 1.05 and waste that too! With an ECU I wouldn't be able to do that, I would be stuck with full time 1.05.....shame!

But Borgan is right also, if you are not confident in what you are doing and dont understand the principles it is perhaps better to leave it to an 'expert' tuner to do the work for you. Be aware though that once you have bought the ECU, it will need fitting and then programming on a rolling road at somewhere between £50 and £100 an hour on top of the £900 purchase price! I would advise anyone doing these sorts of mods to learn about them and become confident enough to do them yourself. Its not really rocket science, and the satisfaction you get from knowing how and why the mods work, and actually achieving them is great.

[borgan]

With an efficient fuel map your economy will improve. Initially, it won't as you'll want to enjoy your new found power gains whether you've added a boost controller or ECU. With your boost controller off you'll still be running rich. On part throttle you'll be burning the perfect amonut of fuel - as long as the tuner you've used is good.

If the Yamaha Seca motorbike has a factory upgrade allowing boost of 12 psi from 1 turboINSERT INTO post VALUES (baby turbos thread); why shouldn't the twin turbo parrallel setup on the VR4 run effectively to around 18psi?

[zedy1]

i think if i put me head into it ill get it right but as soon as i open the manual for the boost controller i get disturbed so never end up reading so i contact my mate dave and ask him a few short cuts

[Spirit]

This has turned out to be a great discussion and thanks for all the tips/comments/opinions - just leaves me one issue though, whichever route I take INSERT INTO post VALUES (ECU or boost controller) I have no-one local to help :Cry1:

[enigma]

I have started a new discussion thread on turbocharger boost spikes and general control theory.......................

Can you tell I leave work at 12 on a Friday?!

Follow the link!

[SGHOM]

Well !! this is my next upgrade, after I get the induction kit, & the de-cat fitted. And there's no way I'm going to try & fit it !! :nono:

[enigma]

mmmmmmmmmmmm yummy! Hope it performs to your liking!

[Spirit]

Derek

Where did you purchase it from ? Was it direct from Australia, and if you don't mind how much did it set you back ?

Cheers

Pete

[enigma]

Looks like an easy install to me!

[SGHOM]

Originally posted by bigdaveakers
Looks like an easy install to me!

easy install ??? might be for you, but I'm not going to attempt it !! once I get the other bits done, It's going to a tuning specialist reccomended to me to be installed , set up & tuned. I suppose if I'd shopped round etc, I could probably found it cheaper than the £355.49 [ inc vat ] I paid. bought it from POTN. comes with a lovely big window sticker though !!! "NITROUS SOLUTIONS" now, where shall I stick that ?? imprudent suggestions may not be acted upon !!

[chris g]

Turbosmart kit is available from Owen Engineering who are renowned for turbo and Unichip work so I guess they will supply, fit and set up the car for desired power etc