Aygo with a twist
 

Hi Eco folks, on this god forsaken place - the internet forums.

I'm new, and do have a somewhat misplaced agenda - I'd like to get my Aygo faster! Car enthusiast, when asking for performance mods have often been dumbed with the phrase - "you should have bought another car". I'll prove them wrong.
And before you call me an idiot - I know it won't be fast - fast. I own a 400hp 1985 MR2 running 11s, so I know what a fast car is :)

The build
Will have a high focus on lower weight, areodynamics, gearing, lowering resistance and in general being on a budget. The car it self weigh in at 680kg dry. So far I've estimated a drop to 560-580kg depending on the actual weight and what is included in the specified weight. The car will make about 90-100hp. Goal is 6s 0-100.


I have some questions that this place might be the best to answer.

How much does better areodynic impcact acceleration? Specific examples at 50-100-150km/h will be much apreciated.

Alternate delete:
Does anyone have any idea of how much power a car would need pr km - only running cars vital components like sparkplugs, fuel pump/injectors etc.
-Any example with running a battery flat withouth alternater is appreciated, especially with battery specs listed.
- Goal is to lower weight and power consumption.
- I'm planing on running a 12v 3.5Ah Lithium battery, so power is limited.

Lowering a car vs underbody panels
Ofc now I can't find the link, but basicly it explained that a flat-bottom and smooth object would actually increase cD when bringing it lower to the ground. Can anyone shed some light on this?

Lastly I'll list my ideas to the curiosity folks:

Areodynamics:

• Duck tail/semi-tail
• Underbody panel
• Side mirror mod or delete
• Lock/handle delete - side smooting
• Lexan windows sealed to smoothen window/door
• Sealing small gaps
• Front partial closed off and/or changed
• Lowered as much as possible - chop chop is considered over expensive coilover
• Rearwheel side skirt
• diffuser

Performance/engine mods

• Lower gearing 7% with wheel setup
• Lighter wheels - Enkei with 165 50 R14 10,5kg front - if traction is less of an issue Lupo wheels will be used instead lowering it 500g (4,4kg vs 4,9kg-Enkei)
• 3-1 manifold with 1,75" straight piped exhaust
• Ram air "forced" induction with little to none filtration - from an open spot on the front.
• Generel porting and flow optimizing
• Low viscosity oils
• Lighten flywheel
• Alternater delete or full throttle off switch
• Electric water pump - Depending on battery/alternater situation.
• Lastly getting i ECU tuned and rev liv to 7500rpm

Weight
All in on weight reduction, cut'n remove etc.
Lexan window
Lithium battey

Lastly - and this might be controversial, but are there any facebook groups with eco modding in focus. I am sorry if this voilate any rules. But I dont expect much activity on these old forums. So a bigger user base might be achieved on facebook.

Greeting from Denmark
Johnny

Welcome to the forum.

There are quite a few alternator related threads that are active at the moment. From measurements on a completely different car, the minimum the ecu and ignition needs is approx 6-10A. So your lithium will last about 10-20 minutes before it needs to be recharged, assuming it can deliver the necessary amps.

I’ sure others will chime in shortly.

12v, 3.5ah? I'm hoping that's a typo...I have bigger batteries for my cordless tools!

It might work for voltage stabilization while the lead is disconnected, but not much more.

Thank you for your reply. I guess low battery power also will lead to bad fuel beffeciency if fuel pressure drops.

I think I'll go with a bigger battery pack, electric waterpump and an alternator full throttle kill switch.
According to what I read here and there, although it seems a bit high, the water pump draws about 8-10hp and the alternator 8hp at high rpm. So the increased power overrule the loss of 15kg.

Those figures seem a bit high.

If you want the exact same effect, you are kooking ad delivering a kW.

1HP is roughly 3/4 kW

At 12 V you are looking at 80A per kW.

Lithium batteries if big enough do not have a voltage sag as they are consumed. And they have a higher voltage compared to lead acid.

Cant find much about info on alternators, but electric water pump dynoed shows a straight up 6-8hp! On stock Water pump delete. Some state that a water pump power consumptions multiply by a factor of 4 every time the RPM doubles. And like a boat propeller the speed exceed what can actually move at high rpm.

Look at pictures google'ing "electric water pump dyno".
Sorry cant linke urls yet due to have posted less than 5 times :/

Maybe Ecomodder isn't the place for you?

The power needed to push an object through a fluid increases as the cube of the velocity. Mechanical friction increases as the square, so increasing speed requires progressively more power.

The plenum between the ground, the underbody and the tires is complex. Smoother is better. Lower has less frontal area (the tires). A central jet and correct diffuser angle are important.

One of these? https://en.wikipedia.org/wiki/Toyota_Aygo

First or second generation? Gas or diesel? This vehicle is already probably well sorted, there might not be much low-hanging fruit. You probably won't gain much without a full boat tail. That would gain you about as much as the engine modifications.

Don't get me wrong, I love these forum, but they're dying unfortunately :)

It's the 1. Gen.It's lighter. Though the 2.gen does have about 15% better fuel economi on paper.

Would just be nice to see an example of an optimized car vs stock.

Every little detail will have a significant impact, because of the low weight.
Lowering gearing feks pretty much has a 1:1 in lowering acceleration times. Light wheels can easily shape 5+% off. And every HP will count.

So if aerodynamics could be put to play a positive role that'd be nice :)

And Facespook is not?

An other alternative would be Reddit or an Aygo-specific forum

Any serious attempt at weight reduction would lead to removing sound insulation and upholstery. Unfortunately.

Toyota designed the vehicle for a very general use case. Look at what you're intended use is and design accordingly. An in-town commuter would be different than an Interstate road tripper. Camping? Hauling building materials?

If you do the engine mods will you do some short-course racing? What does the undercarriage look like?

I've been part of Aygo forums since 2008. Had mine for 10years/250.000km. They are pretty much dead all of them.
But let's not discuss that any further :)

The car will firstly be set up to a short burst acceleration. If proven worthy I'll take it for a spin in fwd NA streetlegal class dragrace.

Later perhaps trackday. 165 55 R14 Nankang NS2R would most likely be perfect for that.

The car takes on HP nicely. Airfilter proven to add 3-5hp depending how low the trmp get. And bigger diameter exhaust lets off 6hp in peak range. Tje ignition timing is set to be able to run with the worlds worst fuel.

Underneath could use som straighten out, no covers whatsoever. Only doubt Ihad was the smooth underbody vs lowering.

I have a friend who does circuit races with the BYD F0, which is basically an Aygo clone featuring the variable valve motor.

Easy to get it to handle, but not much you can do that will make a dent in the performance difference to bigger-engined small cars like the Mirage. Though if you do get 100 hp out of the motor, that would be fantastic.

Before significant ride height or undertray modifications, you might want to look at creating an airdam for the same effect without compromising suspension stroke.

Doubt you can get 6s 0-100 with 100 hp. Maybe with around 130. Target weight of about 560 kg, given the frontal area, maybe you can get 7s. Depends on gearing and torque. But it will be fun to see how fast it can go.

The 1krfe engine has proven to make 90-95hp, just by exhaust, open filter and a tune.and the engine is willing to take 8000rpm without failure. So with optimal flow along with lighten flyweel the power band could be extended as it drops afye 6k rpm. 6s might not be achieved. The goal was originally sub 7s. Which I believe in. Being light and with small wheels I can really shave alot of weight off the wheels compared to heavier car with same p/w ratio. A 300hp/1400kg Golf would easily be +20kg to get any decent grip. And lower friction due to narrow tyres as grip will be less of a problem. Looking at other cars with similar p/w ratio 6-7s is not far

Reports of our death have been greatly exaggerated.

I'm off to class now so I'll come back to this later and write more, but this is a simple physics problem. My hunch is that the answer will be physically or financially unworkable, though, if you're looking for a car that does 0-100 kph in 6 s on 100 hp.

Honda Integra 4.gen p/w ratio 6.3. 0-60mph 5.8. 0-100 is 6.3 because of 2. Gear not reaching 100km/h. Will be about the same p/w, 2.gear +100km/h, 4-5kg lighter wheels, low friction/narrow tyres. 100hp was also just a goal, which I'm sure I'll go beyond. I cant be far off :) but time will tell.

A stock Aygo will do 0-100 in about 12.5-13s messured with a 20hz gps called Draggy, which is as close to true figures as it gets.

How would you feel about dragging around a 3ft boat tail? Given that it has more plan taper above the wheel arches it would have an upper and lower section like this:

https://ecomodder.com/forum/member-f...6-12-58-10.png

Have you never considered something similar to the eAssist/BAS-Hybrid system instead of getting totally rid of the alternator?

I did, but I figure that it'll be cheaper and easier to just make a cutout switch so the alternator freeruns when full throttle.

So the I'll get an electric water pump and freespin alternator, that should set of a few HP :) I might have too high hopes, but I hope for atleast 10-12hp which would be a great gain :) Sets hope for 120+ hp.

Freebeard - Not really :p

https://ecomodder.com/forum/member-f...31-1-26-08.png

How about a boxed cavity?

12.5 sounds reasonable. The Mirage 1.2 with 74 hp but less weight and more torque does it in around 11.8. (Garmin GLO, 10Hz via RaceChrono... I've V-Boxed the car, but with a passenger, and it was at 12.5 then. Weight really does a number on these small cars!)

100 bhp and seven seconds might be a very big ask. We did some development work on the Mirage engine when my friend was still in the country, and on these small motors, with basic bolt-ons and an ECU tune (no redline work), we found some 10 hp with a chip and bolt-ons. Granted, with an aggressive tune and the redline raised, you might eke out another few hp, depending on how under-rated the stock motor is and how restrictive the stock exhaust is. (have any links to what modified KRs are doing there? I have friends who'd be interested)... I guess your ceiling is higher, as the KR probably isn't as optimized for low rpm use as the 3A92... which could really use a bigger throttle and more cam.

The electric pump and alt-delete won't gain you as much as on bigger cars. Smaller accessories, smaller draw. Flywheel will help responsiveness, but not much more. I guesstimate you'd gain maybe 3-5 hp for your trouble de-accessorizing the engine.

But then, I'm not familiar with modifying the KR-FE, but say you can hit 100 hp, you still need Super Seven levels of lightness and grip to hit the 7's. So yes, you need to be below 600 kg. Stock weight of the Aygo is around 860+ kg, don't know where you're going to find much in savings past the first fifty or sixty. Full interior strip on one of these cars should net you maybe an extra second off the 100 km/h times, but past 60 km/h or so, at these power levels, it's all aero.

Lightest kerb weight is 780kg for a 3door with minimum equipment. But I'm not sure what this includes. In Denmark we use a standard of saying dry weight+120kg is kerb. However, EU standards says car with fluids etc +75kg = kerb. And all are listed as 800kg. Every car also comes with a full size spare tyre. 13-14kg.

The water pump is the same as many other cars with bigger engine the gesring of the pulley migjt be different. The alternator is 80amp I believe, so not far off bigger/golf class cars.

Waterpump is about 2500DKKR/400$/350€

I can post some figures later, in the meantime heres a 107 which basically is the same car, making 92hp. With intake/exhaust and a tune.
https://youtu.be/8Cc3xOsWyCY

Another I know of made 95hp with stock manifold/cat. The dyno might be optimistic, but it showed a difference in 12hp before/after.

The stock intake drop to 96-97kpa starting from 3500rpm. A filter will let it up to 100-101kpa. A little science will say 3-4hp depending on how low you can drop the temperature. A bolt on 42mm ID exhaust pipe will get i 6hp in peak rpm. I had this same exhaust, wich made the same difference ad stated in the video.
https://youtu.be/gVh3rjV5Spg

I'd rather try to adapt some motorcycle-style stator instead. Assuming you won't need too much accessory drive, could eventually get rid of belts and pulleys entirely, plus having a reasonably constant electric power supply for the ECU, ignition and the electric water pump, among other essential components.

The difference in quoting standards is the rub. But I expect the weight stated is to the same standards as the stated weight of the Mirage, due to the 0-100 times.

It's likely the KR-FE is more throttled and less optimized than the 4A from the factory (less headroom for modification on newer engines).

True, what matters is what the before and after numbers are, rather than the dyno readout (have had so many headaches over those over the years).

Mods aren't always additive. They give and take away, and sometimes once you've freed up the breathing/exhaust enough, extra modification will make less.

It's an interesting project, though... looking forward to seeing what numbers you can get, and what advantages in 0-100 and quarter mile times you can produce from this thing. :)

Tje 1krfe is set for eco driving, which limit the airflow. So getting it to keep increasing or at least not drop drastically after 6500rpm will be a challenge.

On a note to the 0-100 times, I've had a little chat whit a racer from the Aquila Synergy league, which is based on the Aygo platform. The minimum weight with driver must always be 500kg, and 400kg without. They are 4.5 p/w ratio - he claims they do 0-100 in about 4s. So I can only be realistically optimistic.

So drivers over 100 kg are at a disadvantage.