SOHC 103hp vs. DOHC 128hp vs. DOHC 137hp - differences

[l3mur91]

This thread is about engines from 323 BG ('89-'94). Not related for BP's engines from MX-5 or Lantis ('94-'98).

TECHNICAL PARAMETERS

1.8 16v SOHC 103hp

Power: 103KM / 5300rpm
Torque: 148Nm / 4000rpm
Compression ratio: 8.9:1
Compression pressure: 12.2bar

1.8 16v DOHC without catalytic converter system (?) 137hp - produced up to march '91

Power: 137KM / 6500rpm
Torque: 160Nm / 4700rpm
Compression ratio: 9.8:1
Compression pressure: 13.8bar

1.8 16v DOHC with catalytic converter system (?) 128hp - produced since april '91

Power: 128KM przy 6500obr./min.
Torque: 157Nm przy 4500obr./min.
Compression ratio: 9.0:1
Compression pressure: 12.8bar

DIFFERENCES

Airflow meter

In SOHC engine there is the same airflow meter like in 1.6 engine. Sign: "S".



In DOHC engine with catalytic converter system there is little bigger airflow meter and it have other voltage. Sign: "U".



In DOHC engine without without catalytic converter system there is airflow meter with sign: "V".
We don't know anything about differnces between "U" and "V". And we don't know if it can work interchangeably.



Fuel pump

In DOHC engine fuel pump is bigger that this from SOHC, and more effective.
SOHC vs. DOHC:




Exhaust train

In SOHC is other exhaust manifold and other pipes have smaller diameter.
DOHC at the last part have two endings, SOHC one.


Pistons

Pistons are the most important deiffernce between these engines. This is the reason why every engine have diffent compression ratio.






VICS System - Only DOHC

DOHC with catalytic converter system:
Closed to: 5100rpm
Opened from: 5100rpm

DOHC without catalytic converter system:
Closed to: 4800rpm
Opened from: 4800 rpm

There is diagram from roller performance tester. One test with closed VICS and second with opened VICS.
CLICK


ECU

BP01 - ECU for SOHC
BP05 - ECU for DOHC with catalytic converter system and Lambda sonde/ Lambda probe (?)
BP22 - ECU for DOHC without catalytic converter system and without Lambda sonde/ Lambda probe.


Step motor

In SOHC and DOHC (with catalytic converter system) step motor is under choke.
2-pin's plug.



In DOHC (without catalytic converter system) for "slow rpm's" resposible is team of three electric valves installed under intake pipe.
6-pin's plug.




Wiring loom

All 3 engines have different wiring looms.
Between SOHC and DOHC (with ccs) is one little different. SOHC haven't signal for VICS. Near injection rail there is plug: in DOHC 8-pin's, SOHC 6-pin's.
These 2 pin's is exactly signal for VICS.

In DOHC (without ccs) there isn't plug for Lamda sound and there isn's 2-pin's plug for step motor. Instead it there is 6-pin's plug for team of three electric valves.
Signal from sensor of power steering pump don't go to ECU but straight to electric valves in step motor.


Clutch

SOHC: Diameter 200mm
DOHC: Diameter 215mm

Transmission from DOHC have other jack shaft and clutch from this transsmision can't be used in other transmission.

Transmission

SOHC have the logest transmission. Sign: "F5M-R"

1. gear: 4.416
2. gear: 1.842
3. gear: 1.290
4. gear: 0.918
5. gear: 0.731
R. gear: 3.214
MAIN : 3.619

DOHC have short transmission. Sign: "G5M-R"
(1.3 engine have shorter and thus transmission from 1.3 is the shortest)

1. gear: 3.307
2. gear: 1.833
3. gear: 1.310
4. gear: 1.030
5. gear: 0.837
R. gear: 3.166
MAIN : 4.105

Overhead camshaft

DOHC (with ccs) have other camshaft's than DOHC (witohut ccs).
In DOHC (without ccs) suction cam shaft have sign: "BP22" and exhaust cam shaft have sign: "BP05".
In DOHC (with ccs) suction cam shaft have sign: "BP05" and exhaust cam shaft have sign: "BP06".

exhaust cam shaft - "BP06":


exhaust cam shaft - "BP05".


suction cam shaft - "BP22"


Every cams without without suction cam shaft have 8.6mm lift.
BP05 have 8.1mm lift.


----------------
Original post by Jacek176


----------------
I tried to wrote this correctly with good grammar. If something is wrong please correct it. I don't know too if name of every systems and parts are good. I translated every proper names and I hope that made it correctly too.

I have some information about complete engine overhaul made by Jacek176 too and some information about tuning of BP engines. Everything is on experiential of Jacek176.

Enjoy !

[bogaut]

good info! never seen a 'v' code vaf. didnt realize there were non-catalytic converter BPs

[KaleoXtreme]

good info! never seen a 'v' code vaf. didnt realize there were non-catalytic converter BPs

Yeah me either. And with higher comp pistons too.

[KAinjection]

I have some questions:

What does this mean?

BP05 - ECU for DOHC with catalytic converter system and Lambda sound (?)
BP22 - ECU silnika DOHC without catalytic converter system and without Lambda sound.

Specifically what is "Lambda sound"

Can you get an ECU pinout or wire schematic for the BP22 ECU?

Can you find out the specs of those camshafts? BP06 and BP22

I am not fully understanding what that dyno graph is showing, it appears to be multiple runs, but which line are VICS open and which are VICS closed, and what is different to make that 1 peak at 162NM?

[l3mur91]

I have some questions:

What does this mean?

Specifically what is "Lambda sound"

Can you get an ECU pinout or wire schematic for the BP22 ECU?

Can you find out the specs of those camshafts? BP06 and BP22

I am not fully understanding what that dyno graph is showing, it appears to be multiple runs, but which line are VICS open and which are VICS closed, and what is different to make that 1 peak at 162NM?

You know... it's little difficult to translate names of car parts from one to other language.
Lambda sonde / Lambda probe - I don't know which is the correct version of it. Something like this: CLICK

I will try to get wire schematic or pinout for BP22 but I don't promise anything

I know that this dyno graph isn't enough clear and simply to understand, but I have only this one. I will check our polish thread and try to explain what is what.

[KAinjection]

We call that an oxygen sensor or Air Fuel sensor. I understand now thanks.

I have access to a BP22 ECU, and am curious if i can change it for my BP10. Mostly curious what the difference between the idle control valve is between the 2 ECU.

I wouldn't mind getting a set of those cams, but curious on the profile (specs) of them. Thanks for the help

[l3mur91]

Ok, I have something like this, but in Polish...
You can translate or wait when I will have some free time to translate.

[MD323]

All 3 engines have different wiring looms.
Between SOHC and DOHC (with ccs) is one little different. SOHC haven't signal for VICS. Near injection rail there is plug: in DOHC 8-pin's, SOHC 6-pin's.
These 2 pin's is exactly signal for VICS.

one of the wires is for VICS the other is for the fan switch which is moved to the injector harness on the DOHC. also the DOHC motor has a 2nd wheel in the distributor and an additional signal wire for it.

[KAinjection]

Ok, I have something like this, but in Polish...
You can translate or wait when I will have some free time to translate.

Thanks! I will try to use google to figure it out, but if I get stuck I will ask you, unless you happen to finish before I do.

[l3mur91]

If You will have some fast question You can ask by PM.
The most probably is that I can translate it in friday evening. Maybe wednesday evening.

[jackkpl]

I just found this thread (was looking for bp22 ecu pinout ) and was very surprised to see my dyno sheets and some "cam research" pictures

As for explanation for dyno:


131 hp is stock ecu, stock 1.6 oem exhaust (middle pipe and last muffler). Car was just after hand made head repair and mild porting.
134 hp was with open bonnet - cooler intake air yielded gains throught all the rev range
118 hp is with vics constantly closed, the rest is with vics open (had broken vics valve, so had to switch it manually)


My next mods were adjustable cam sprockets:


This run was done on LPG with BLOS - that is why numbers are a bit lower than previous 131/134
Retarding intake cam gives good top end, but takes away mid range
Advancing intake cam gives huge gains mid range, but looses a bit top end

THe last mod i did was Escort rs 4-2-1 exhaust manifold (had to get new head flange, and weld middle pipe flange to connect). The rest fits well under oil pan. It gave huge gains in mid range

This is a bit "paint" work as dyno guy exported dyno graph in some ****ty format.
Red graph is on PB95, blue and green is LPG.

With 4-2-1 headers and advancing intake cam 3-4 degrees the car became an LPG driven TDI. I could easily overtake most of the cars in the city in 2-5k rpm range. It was so much fun to drive.

After that i stopped playing with N/A and got Eaton M62 - the best decision ever in tuning 323F
Hope it clears things a bit, even though it is an old thread

[Krushh]

Silly Question:
Does the SOHC share the same GEARBOX (Not Tranny) as the DOHC?

[MD323]

picture of what your calling a gearbox would help

[l3mur91]

Not the same.
Differences are ratio of gearbox and clutch. But You can fit every gearbox to every engine of b-series after fit suitable clutch if I good remember.
Good idea is garbox from 1.3 16v to 1.8 DOHC. In Poland we often choose this road, to make faster our 323.

[Krushh]

Here is the situation. I have a 323 se (1800 cc 16v) 5spd gearbox. I want to know if its the same box as the 1800 dohc gearbox. I am wondering if it can handle ~250 hp!