N/A VVTi Supra with Dastek Unichip dodgy dyno figure

[Guest Littlecbigd]

This is my first proper post here, but has anyone else had a Unichip fitted to a N/A VVTi Supra?

I am now running with a full decat stainless exhaust, HKS SPF induction, and just had the Unichip fitted at Dastek HQ in Fife....the car has felt quicker with each mod.

But....the readout I got from the rolling road was only 219 bhp (engine I presume) which was a little disappointing given that these things are supposed to be 225 as standard.

Has anyone else got a VVTi N/A with similar mods who can tell me if I should be worried/complain/happy etc.

 

Cheers.

[CJ]

I was always of the opinion that the MKIV could not be "chipped". Or is that just the TT?

[Guest Littlecbigd]

Nope - have a look at http://www.dastek.co.uk.

Apparently they can chip anything with an ECU.

I used them as Superchips don't do a chip for the N/A Supra

[Alex]

Not sure CJ....these companies never explain what they are doing when they chip it!

 

Littlecbigd : Did they fit an additional box of tricks to your ecu? Or open up the ECU and fiddle?

 

The HKS SPF is a waste of money - many posts about the inherent dangers of such items - it will cost you power...but make lots of noise.

 

EDIT - ahh it's a Piggyback so it's just like fitting an eManage or SAFC...only you can't mess about with it.

[Faye]

Wow, at last an NA VVTI Uber rare supe only downside is that I'm pretty sure that no one else on the board, so comparisons could be a little difficult.

 

Any pics???!!!!

[Nic]

Did they explain to you what the Unichip was suppose to do? How much did it cost?

 

As Alex says, bin the pod filter and re-fit the stock airbox, as this will be costing you power.

[Guest Littlecbigd]

Its an additional box thats pinned into the ECU harness.

Whats all this about the HKS sapping power?

[tDR]

I know Dastek - they're local. If anything, their RR is said to be average to a little optimistic with their readouts. What was the power before the unichip was fitted and mapped? Normally they do a before and after reading.

 

Unichip is a decent piggyback but can't be user mapped - only they can map it.... bit like HKS FCON V lol /dons flameproof suit

[Guest Littlecbigd]

before - 210 bhp

after 219 bhp

 

Sorry Faye - on works laptop at the mo and don't have any car pics stored on it.

[Whitesupraboy2]

219bhp is gonna be at the wheels or maybe the hubs.

 

So whos gonna say the BHP of th car then

[Guest Littlecbigd]

So is 219 bhp at the wheels with just a pipe, induction and a chip good for an N/A VVTi?

Everyone - please keep the lid on the old wheels to engine BHP conversion can of worms.

[Whitesupraboy2]

dont seem too bad to me, i believe it about 190ish as standard at the wheels so uve got a good, few more horse's extra.

 

How is the bottom to mid range. I find the NA only really comes alive above 4,500 - 5000 revs

[Guest Littlecbigd]

Yes - I agree - there is a definate pick-up in acceleration at 5ooo rpm - I imagine this is when the VVTi kicks in or something?

The dyno graphs also showed a jump in power and torque at 4000 and again at 5000

[Whitesupraboy2]

If you get a 2nd jump as such must be ur VVTI as im just ur bog standard NA im afraid. But they are good figures for what you got.

 

I think standard air box with sports filter may get you better response or at least get a heat shield for the filter.

 

You going to do the Cams at all?

[Chris Wilson]

Sounds about right, you may pull a few more BHP by binning the HKS "filter" and refitting the stock set up. i doubt you will find much power from a Dastek as the thing is well mapped to start with, and for decent fuel!. Tuning any modern N/A is VERY expensive, see below for a guide as to why.

 

Whilst not wanting to put a damper on your aspirations towards

better performance,the following general stuff in regard to tuning

late,fuel injected,electronically managed engines may help.

 

Post the early eighties,more and more manufacturers went to electronic

management of ignition and fuel,via fuel injection,and mapped ignition

systems. Most fuel injection systems had one immediate impact. They no

longer need a restrictive venturi (narrow throat) in the carburettor

(s) to pull fuel out of the fuel bowl of the carb. Fuel injection

*injected* the fuel under high or very high pressure. No restriction as

such,and hence less of a power loss. Management of the ignition and

fuel suddenly meant engines could get away with running camshafts with

greater overlap,and higher lift,too. The old advance weight disi,and

velocity sensitive carb limited what cam profile could remain

driveable, without hesitations,poor low end performance and flat

spots. To a large extent electronic management allowed much more

freedom in valve sizes,port shapes,and cam timing,as well as running

the engine at the best amount of ignition advance at all loads and

RPM's without detonation,on differing fuel qualities,via knock sensor

technology.

 

What I am slowly getting at is that it is *much* harder to get

anything like a useful power gain from a modern,well designed,16 valve

production engine on electronic management. The exhausts are free

flowing,as are the intake systems. One needs to look at further

performance optimisation of the cam profiles,and maybe bigger

valves,stronger valve springs,moves away from hydraulic valve lifters

and mechanical improvements to make higher revs safe,from a

mechanical stress related point of view. Almost any change that has the

potential for a marked improvement in power and torque,will require

different fuel curves (the amount of fuel injected at any one set of

parameters of air flow,temperature,engine RPM etcetera,etcetera),and

different timing curves. One can fudge the fuel,*across the whole

curve*,by increasing fuel pressure via an "up rated" fuel pressure

regulator,but the the weeks of dyno testing to get the fuelling

correct at every point,has then gone to pot ... :-(

 

As for the ignition,there is very little indeed you can do to change

the curve incrementally. Unfortunately,the *correct* answer is an

aftermarket injection system,or at least an aftermarket ECU and

wiring,that allows one to map the curves afresh,to suit your new power

modifications. This is expensive,both in terms of hardware,(maybe over

£1000 for the ECU and wiring loom),plus a lot of professional engine

dyno time to get it all mapped correctly.

 

Sometimes one can buy a complete package,say new cams,different

throttle bodies and manifold,etcetera,that can come complete either

with a modified EPROM for the existing ECU,or an aftermarket mappable

ECU complete. If one limits mods to exactly those which the kit

manufacturer intended,this should work well. If you change any

parameter from the tuners package,the early comments about incorrect

curves again apply..

 

Changing the exhaust *system* or the air filter,on 90% of modern

engines will do sod all.The mags claim this and that,but in reality a

gain of 5 HP on a 120 HP engine is neither here nor there,for a road

car. Humidity variations can see that much change. A rolling road is

hard pressed to accurately repeat to 5 BHP on a figure of 120 HP

total. To get greater gains,say 20 HP,you need to look at fairly

dramatic alterations,both to the mechanical components,and their

related fuelling and ignition curves.

 

Turbo engines are a slightly different kettle of fish,as it is trivial

to raise the boost,and usually to fudge some additional fuelling.

 

Naturally aspirated remain tricky!

 

The easiest/cheapest way to see increased performance is to reduce

weight. Especially rotating weight,for improved acceleration. Do most

people ask the most important question when buying new wheels,after

ensuring the offset and sizing is correct? Do they *uggery :-) They

should take a fishermans scales with them,and weigh the damned

things. The first question a race car manufacturer asks his potential

wheel suppliers is what do they weigh,and what is their rotational

inertia. Simple questions,and the weight,if not rotational inertia,is

easily self assessed performance differences can be

surprising,and worthwhile. Given 3 different makes of tyre,with similar

grip and handling characteristics,go for the lightest..Just weigh some

of the cheap imported tyres against a decent performance make,like a

Hoosier competition tyre that is road legal. The difference is

amazing. As for remolds,they are incredibly heavy.

 

If you are serious,and can live without goodies,buy a car with the

minimum spec. Sun roofs,air con,PAS,electric windows and mirrors,power

seats all can add hundreds of pounds. Lightweight front seats can add

as much performance,in real terms,as a new exhaust and manifold. 40

pounds of fancy stereo gear does nothing for performance ;-)

 

As cars become better,and more highly developed,the art of tuning

their engines becomes more complex and expensive,unless one looks at

the situation with a bit of lateral thinking. Instead of adding

things,think in terms of removing them. Instead of buying a new set of

wheels just for their looks,weigh them,and see if a gain can be had

for free there.

 

Just ideas,some may be practical for your situation,some not,but be

aware it is all too easy to buy so called performance bits,and get the

thing to go *slower* At least the engine in your car starts off as

one of the best basis for tuning available.

[Guest Littlecbigd]

Well my ££ has run out this year for mods I am afraid but I suppose cams are the only relatively easy mod left before we are talking mega-money.

Its difficult to find anyone else who has modified an N/A (without turbo-ing) to get advice from to see what is best.

[Marty]

interesting read..... but i think my eyes have just burnt out reading all that from chris

 

Littlecbigd... the reason you Hks is sapping your power is because you no longer have any protection from the engine heat, thus your filter will be sucking that in aswel, the standard air box is very well designed and ducted, just a replacement element would do

[Chris Wilson]

A cam change needs a mappabl;e ecu in order to get them to work, and if it's an auto the gearbox should be re mapped to change later and not rely on the dwindling torque at lower RPM's it will have. Finding cams for an N/A VVTi may be impossible short of having some made.

[Guest Littlecbigd]

Thanks Chris - that was a very educational reply!!

I understand what you are saying and doubt I will be dabbling with the engine much further after that!

I will try whittling a heat shield out of something and spend half a Sunday comparing that to the standard airbox to see how it "feels".

BTW - its a manual 'box - Gunmetal grey N/A VVTi 1999 reg Manual and in mint condition very rare I am told ?

[HunterJ]

I have the unichip in my Celica GT, made a difference in power, torque and fuel economy... They have only just completed the new version of the chip that is fully compatible with TT.

 

I'm tempted to get my TT done - I just don't have the cash (around £550 ex VAT all in).

 

Jamie

[Nic]

£550 + vat, does that include fitting and dyno time? Fitting an Emanage Ultimate wouldn't be a lot more than that and I'm guessing would be a lot more versatile on a TT.

[HunterJ]

Yeah, that includes fitting and dyno time. They recon it is quite a bit cheaper that the emanage... I've not looked into the emanage system but, isn't the programming software quite expensive?

 

I think it was £311 ex VAT all in for the old version of the chip I have on my GT.

[Nic]

Yeah, that includes fitting and dyno time. They recon it is quite a bit cheaper that the emanage... I've not looked into the emanage system but, isn't the programming software quite expensive?

 

I think it was £311 ex VAT all in for the old version of the chip I have on my GT.

 

I supply the EMU package for the TT for £488, see details [thread=51612]HERE[/thread], this includes everything you will need. The new Emanage Ultimate comes with the software included.

[HunterJ]

I see, so really the additional costs would be for fitting and dyno time... any ideas on costs for a "standard" fitting and tuning session?

[Nic]

I see, so really the additional costs would be for fitting and dyno time... any ideas on costs for a "standard" fitting and tuning session?

 

Not sure what the mapping costs are, I know Ian C (the Emanage Guru) does mapping for a very good price though. I supplied 'Chipmunk' on here with an EMU recently which he is getting installed and mapped this weekend I believe so may be worth contacting him.

 

The EMU includes a lot of features that I doubt will be included on the Unichip, the package also includes a pressure sensor, so that the EMU can be mapped against boost pressure.