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Jack-Lee 07-08-2013 03:49 PM

Engine mod (BJ 1991)
1 Attachment(s)

my project go forward.
Beside the aerodynamic mods i modified the engine.
Currently a 55PS Mono-Injection 1.3l assembly are installed.

New Engine:
modified "3F" 75HP Multipoint 8V

-new DIY Manifold (oscillating tube charging)
-new DIY Exhaustsystem
-higher compression ratio
-modified head ("Back Cut" Valves, polished exhaust port)
-modified controlbox (no wide-open-throttle enrichment, deceleration fuel cutoff from 1200U/min [currently 2000U/min], mached to "super" gasoline)

-114Nm at 2000U/min !
-Max 131Nm at 4500U/min
-Peak Power 71kW (95Hp)
-BSFC 256g/kWh at best point (about 2500U/min), 265g/kWh average from 2000-4500U/min

Stock 3F:
-97Nm at 2000U/min
-Max 99Nm at 3200U/min
-Peak Power 55kW (75HP)
-BSFC 263g/kWh at best point (about 2000U/min), 275g/kWh average from 2000-4500U/min

currently Engine (AAV 55HP)
-88Nm at 2000U/min
-Max 95Nm at 3500U/min
-Peak Power 45kW (55HP)
-BSFC 272g/kWh at best point (about 2000U/min), 280g/kWh average from 2000-4500U/min


So i save only 5% fuel, but the engine is almost new after the rebuild, so the difference is bigger.
Also i could drive with a looooonger gearbox :)
by the way, ive double the output power :D

The picture show the difference between stock and mod.
Sorry for the grid, the two diagramms had not the same y-axis.

Jack-Lee 07-10-2013 06:30 AM

1 Attachment(s)

i modified the engine again.
Smaller! runners
smaller valves
shorter Manifold with smaller diameter

136Nm! @ 4500U/min
better enginie efficenty

In the picture: comparation between my currently and the next enginie

JasonG 07-10-2013 08:01 AM

Looks promising, keep up the good work Jack.

Jack-Lee 01-16-2014 02:26 PM

7 Attachment(s)

latest Version with 141Nm@4500U/min and 92HP@5000U/min

And a few Pics from the first "real" steps.
The engine are now by the tuner.

-new pistions (incl. drill and honing)
-new valves
-new bearings
-new sealing
-higher compression
-other cam
-other alternator
-DIY intake manifold
-DIY exhaust

renault_megane_dci 01-16-2014 03:14 PM

That's way cool but could we get more pics of oily parts and namely your DIY parts, assembled engine and such.

So you have the facility to dyno run the engine or is it an engine simulator ?

I would really enjoy more details like valve size before and after and such.
Also, what is the cam duration ?

Jack-Lee 01-16-2014 03:17 PM


my english is bad, so i doesnt write all the think that i could write.

Name the Parts? There's normal Motorparts (Pistions and so on)

I clean the Head and mill a little "combustion chamber". Without sharp edges the pinging risk is lower (other changes at the pistion)
The Exhaust is finished, but i had no photo on my PC :/

The Valve are standard, but the valveseat is changed an the valves milled to be lighter (lower springstiffness -> lower losses)

The data in my last post are simulated. But the Motor (when finished) are fine-tune on a dyno.

renault_megane_dci 01-16-2014 03:22 PM

You little teaser ;-)

If your english is not good (not buying it any second) that gives you more of a reason to post more pics !
Also, cam duration, valves diameter and CR you can write in german ;-P

RustyLugNut 01-16-2014 03:52 PM

What are the units for your BSFC.
Those are very low numbers.

Jack-Lee 01-16-2014 03:52 PM


Cam Datas:
CAM from a Polo 6N with ABU Engine
111.5° ATDC
Duration @ 1mm 211/215
Max Lobe Lift 9.4/9.6

Standard from "G40" (exhaustvalve with natrium)
Intake Valve:36mm (Port 30,5mm)
Exhaust Valve:29mm (Port 26,8mm)
Valves polised and the ports are aerodynamik tuned

Intake Manifold:
Length 300 (standard about 130)
Runner Dia: 30,5mm
Made of Alu or CFK, im not sure what material i use.

Exhaust "Fächerkrümmer" 4:2:1
Section 1 (from each cylinder): 32mm (the "step" from head to exhaust minimized the reflow in the cylinder)
Section 2: (for 2 cylinder) 45mm
Section 3. (for all) 50mm

@rusty lug: What numbers you mean?

RustyLugNut 01-16-2014 04:11 PM

The chart you posted for bfsc.

Originally Posted by Jack-Lee (Post 407430)
@rusty lug: What numbers you mean?

Gasoline engines usually come in at right about 0.48 pounds/horsepower*hour in British units. A very good gasoline engine or a basic diesel will dip down to 0.42 lb/hp*hr. Large diesels used in power generation or ocean going power plants can dip down to 0.28 lb/hp*hr.

Your simulated engine is below that at just below 0.25, but it may be an issue of unit measurements. I just wanted to clarify.

Jack-Lee 01-16-2014 04:32 PM

SI system
g/kWh !

RustyLugNut 01-17-2014 03:57 PM

That would mean a VERY low fuel use!

Originally Posted by Jack-Lee (Post 407434)
SI system
g/kWh !

The average gasoline engine has a thermal efficiency of about 25% and a BSFC of 325 g/kW*h ( just a rule of thumb for comparison ).

The Atkinson over-expansion engine found in the Prius has a given thermal efficiency of about 36% for a BSFC of 225 g/kw*h.

It would seem the 0.25 is in Kilograms? 0.25 g would be mind-boggling.

Jack-Lee 01-17-2014 04:40 PM

maximal effciency of 36% cannot be possible.
The "VTEC" Engine from Honda reach 215g/kWh at the best point!
File:Honda Insight 5mt.jpg - EcoModder

Heat engine - Wikipedia, the free encyclopedia
Burning temperatures about 2500°C and exhaust temperatures about 1000°C equals a maximal efficency of 54%.
Theoretical efficency for gasoline engine -> 63%

RustyLugNut 01-17-2014 06:13 PM

Let us work backwards from the definitions.

Originally Posted by Jack-Lee (Post 407529)
maximal effciency of 36% cannot be possible.
The "VTEC" Engine from Honda reach 215g/kWh at the best point!
File:Honda Insight 5mt.jpg - EcoModder

Heat engine - Wikipedia, the free encyclopedia
Burning temperatures about 2500°C and exhaust temperatures about 1000°C equals a maximal efficency of 54%.
Theoretical efficency for gasoline engine -> 63%

Gasoline has a power density potential of 0.0122225 kW*h/g. Multiplying that power per gram potential by BSFC:

(0.0122225 kW*h/g)(215 g/ kW*h)=2.62784

Dividing into unity:

1/2.62784=0.381 or 38.1% thermal efficiency.

This is achieved via lean-burn combustion in the Honda Insight. Someone who is intimate with the engine will know more about this. Please make corrections as needed.

The 225 g/kW*h BSFC that has been published for the older Toyota Prius engines would yield:

1/(0.0122225 kW*h/g)(225 g/kW*h)=0.364 or 36.4% thermal efficiency.

This is achieved with over-expansion (Atkinson) cycles.

Both engines were state of the art at the time and were leaps and bounds better ( in thermal efficiency ) than gasoline engines of the time.

Modern engines hope to do better and are closing the gap between gasoline and diesel engines in the measure of thermal efficiency.

Green Car Congress: Toyota targeting thermal efficiency of more than 45% for next-generation gasoline engines for hybrids

renault_megane_dci 01-18-2014 02:46 AM

Thank you for your reply and technical details Jack-Lee.
Congratulations on actually doing stuff.

oldtamiyaphile 01-19-2014 04:10 AM


Originally Posted by Jack-Lee (Post 379563)
-modified controlbox (no wide-open-throttle enrichment, deceleration fuel cutoff from 1200U/min [currently 2000U/min]

I would love a more effective DFCO in some of my cars. My Fiat will DFCO from only 1500rpm and go all the way down to idle - I'm quite happy with that. My MB100 and Jeep will DFCO from 2000 down to 1500, for the MB that often means a downshift, while on the Jeep it's almost useless as there's little need to ever exceed 1500rpm in normal driving.

Is this something any dyno tuner car do for me? Will it cause any drivability issues? Also, what RPM did you chose for the fuel to come back at?

Jack-Lee 05-09-2015 04:13 PM

9 Attachment(s)
i dont write a long time, but the work still in progress :)

-Engine is back from restoring -> drill, honed, new pistons, new bearings, new hyd. valve lifter, new valve, new valve seats, DIY fan type exhaust, other CAM, DIY Intake System (single Plenum Racing EFI), short.. all new! 2200€ ..
-build a new engine in the ventilation System. Same airflow, but only 25Watts instead of 100W with the old thing.
-all screws new
-complete chassis restauration new Brakes, new Paint, and many more
-free programmable engine controll unit


renault_megane_dci 05-10-2015 12:57 PM

I happen to own an Audi A2 with the 1.4 liter gas engine.

Any quick and easy mod you'd had in mind to improve FE ?

I was thinking of knife edging the throttle body shaft but it's already quite involved ...

Jack-Lee 05-02-2016 06:40 PM

1 Attachment(s)
I build in another EFI, with longer tubes.

elhigh 05-02-2016 07:55 PM

We only hear from you about every six months or so, Jack, but you drop us these tantalizing photos and short, maddening descriptions.

"...with longer tubes." YES, we see that! Can we see it in the car, or hear about how it changes the car's performance?

You're waving the steak in front of our noses, please give us a taste!

Jack-Lee 05-03-2016 01:43 AM

2 Attachment(s)
My english is bad, so i didtn wrote long texts here :X

The original EFI was only 180mm long. To reduce the RPM and higher the tourque, i used this EFI. Smaler, longer but with a smooth surface and good tubelining. The "snakehouse"-form equals in a "drill", wich optimize the nebulization at low rmps.
Runner lenghts are now 370mm, the diameter 31 and a smaller plenum.
With the deleted flowmeter (used now underpressure and the temperature to calculate the fuelflow), this big 61mm Valve, a shorter and "cleaner" tubing the intake CFM grows from 116 to 465. :turtle:
A other CAM (from the 1.6l ABU Motor from the VW 6N Polo), a DIY fan-type exhaust pipe, modified motorhead and higher compression (11:1), do the rest.
I hope i get the 145Nm @ 4500U/min @ a BSFC from 240g/kWh.
with the other tunings at the motor, i get much higher tourque and efficency (look at the diagramms)

renault_megane_dci 05-03-2016 04:30 AM


It seems you are using an OEM intake setup. What vehicle is it from ?

Can we see pics of your fan type exhaust ?

What is the 61 mm valve ?

Jack-Lee 05-03-2016 08:14 AM

the Intake is from a 1.6l ABU Engine from a VW Golf3
The Valve comes from a Golf4 with a 2.0l engine.

renault_megane_dci 05-03-2016 09:56 AM

By (61mm) valve do you mean throttle body ?

The HP figures are very impressive, all with OEM parts, a gas flowed head and compression ratio raise ?
Is the curve from actual measurement or a software output based on CFM increase ?

Jack-Lee 05-03-2016 12:04 PM

All with customized OEM Parts.
But the real torque are lower, because i didnt modified the valves.

The curves are made with a (good) software, just as the Stock curve (an there is allmost the same as the maesured one).

And the 61mm Valve is the main throttlevalve

renault_megane_dci 05-04-2016 10:07 AM

To your knowledge, could that part list be applied to the 1.4 from a 2000 A2 ?

I have red the A2 ECU is pretty different and is an issue when going for a turbo setup.
Any chance I could see a boost just with the inlet and cam ?

Jack-Lee 05-04-2016 03:35 PM

without a change in the ECU, the differences could be negativ. (wrong Lambda).
the A2 engine is pretty good, you couldnt make it so much better then mine cheap old thing. ECU modification could be the better way

Jack-Lee 01-07-2017 05:23 PM

5 Attachment(s)
the project still in progress :)
Now i have a second "Polo" for the transition period. So i modified it a little bit.
Its another engine with only 1.0l and 45Hp.
Bigger throttle, other cam for more torque, modified intake manifold for better airflow.
+9hp @ 5500U/min and +12Nm @ 4000U/min and better fuel efficency :)

renault_megane_dci 01-07-2017 06:48 PM


Appart from cam and throttle (holly molly difference !) I dont know what are the three other pics to be honest ...

Jack-Lee 01-11-2017 04:26 PM

18sec(stock) to 14sec. Nice difference:

But.. i would build in a MegaSquirt2 and MPI. More things i could play with.. Goal : over 110Nm and over 65Hp with higher fuel efficency

Jack-Lee 01-12-2017 05:06 PM

1 Attachment(s)
And now i build up the new controller. A "UMC1". Sensors: MAF (main), MAT, CLT,TPS,Lambda.

Jack-Lee 01-17-2017 05:18 PM

Now i modified the head of the motor.
I would build in 29mm/32mm valves with 6mm stem in place of the 28/32mm original valves with 8mm stem. In addition i mill the valve seats to the max for much intake/exhaust flow.
I turn my own valve guides, from CW713R, because theres no guides with 6mm inside and 12,06mm outside on the market. Besides i smoothed the ports and makes the radius as great as possible. So i could realise a 25% better cfm rating.
The intake manifold merge to the head and i install the big throttle from the 75PS GT Engine.

And for better comparability i make a dyno-test with the original Engine:

Jack-Lee 01-20-2017 04:37 PM

4 Attachment(s)
Another work is done: The Valves are ready.

Intake Valve 35% lighter and more aerodynamic
Exhaust Valve 40% lighter.

Xist 01-21-2017 01:36 PM

Is the only difference between the dyno tests the valves?

Jack-Lee 01-25-2017 03:49 PM

No, the three dynostests made directly in a row. Minimize deviation.
The new Valves, the MPI and the modified head should rise the power from 45hp to 80hp and the torque from 77Nm to 115Nm :turtle:

renault_megane_dci 01-25-2017 05:49 PM

Nice work.
You focus on exhaust valve to reduce pumping losses ?
Good to know someone who cuts their own valve guides ;-)

Jack-Lee 01-28-2017 03:01 AM

3 Attachment(s)
I change all Valves. So i could reduce the weight, could work with ne single spring (instead of two) and improve the airflow.

Yesterday i build the elektronik. Works great (on the Table), today i build it in the car.

Jack-Lee 01-30-2017 05:00 PM

1 Attachment(s)
Today the car is ready to roll. :)

Jack-Lee 02-09-2017 01:31 AM

1 Attachment(s)
Oh, i forget to upload the results of the mod with the new fuel injection :)
Nice Tourqe und Power-gain. Now i musst build up the new head and install it.

Jack-Lee 02-17-2017 11:41 AM

8 Attachment(s)
Now the valve-set is complete :) Ready to install.
I could manage 33% less weight and 20% more flow.

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