Kjet performance mods - Page 2

PCH · 06-26-2012, 01:30 PM

NA B21F manifold was designed for low end torque and had some issues with flow on #1 and #4 cyl. Overall flow was better than 21FT but of all manifolds available to me for testing back then the LH1 was the winner, that's why i suggested it.

PCH · 06-26-2012, 02:01 PM

Quote:

Originally Posted by 245gti

Your biggest challenge will be getting enough fuel. K-jet isn't terribly flexible and has its limitations, prompting many to swap in an LH system or go aftermarket with something programmable.

K-jet can provide enough fuel to have fun and get into trouble though. Just watch your AFRs and listen for detonation as there are no knock sensor electronics to alter timing or fuel.

Check out how Porsche dealt with it on 924 GTS (factory racing model 55 built) They got something like 280HP out of 2.0L

K-Jet head out of 8cyl application:

Merged into 4 injector lines:

doucheNozzle · 06-26-2012, 02:07 PM

Quote:

Originally Posted by PCH

NA B21F manifold was designed for low end torque and had some issues with flow on #1 and #4 cyl. Overall flow was better than 21FT but of all manifolds available to me for testing back then the LH1 was the winner, that's why i suggested it.

Bigger plenum is not better for low end torque.

The B21F intake mani is much better than the B230 intake manifold.

PCH · 06-26-2012, 02:21 PM

That plenum volume had a lot to do with needing to keep the air meter plate steady. Especially since it was so close to the throttle. But yeah, some are better than others depending what you want from them. Any manifold and any cam works best at only one specific range- the rest is the trade off.

Volvo69 · 06-26-2012, 10:44 PM

I like the relocation of the kjet. Never thought of that.

PCH · 06-27-2012, 12:10 AM

The 21F manifold was killing the high RPM potential of the K-cam, so it had to be done to experiment with something different.

242 glt · 06-27-2012, 03:03 AM

Still have some q about your pics, umm the b20 injectors how are they held in? Also what is a l.h 1 intake? I do know there is a late and early style b23/ b230 intake. Also the tb in your pic is upside down? whats up with that?

242 glt · 06-27-2012, 03:08 AM

Also just for the recored im not talking about the b21ft intake im talking about b23/b230, someone mentioned the b21f intake as a upgrade and i think that would flow good, i have one, just not the correct linkage for it..

PCH · 06-27-2012, 12:05 PM

1981,1982 LH1.0 Intake had TB mounted like that from the factory, so it's not upside down. And the injectors are the usual kjet, just had to improvise the mounting.

swiggy · 06-27-2012, 12:22 PM

Quote:

Originally Posted by PCH

The 21F manifold was killing the high RPM potential of the K-cam, so it had to be done to experiment with something different.

Thats interesting you say that, since the K cam came stock in engines with the B21F manifold (B23E).

PCH · 06-27-2012, 01:19 PM

The B21F manifold did the best job of providing torque (long straight runners) and smoothing out the vacuum (large plenum). Running K cam with its overlap specs required that. But just from looking at the B21F manifold its obvious that its not high RPM friendly.

doucheNozzle · 06-27-2012, 01:27 PM

A large plenum is for high RPM.

PCH · 06-27-2012, 01:59 PM

Yes and no. It all works together and affects different things depending on RPM, load, boost, etc. B21F manifold is a good upgrade over the original Turbo one in part because of its large plenum. But it was not developed for turbo application originally. And what about ITB's? They are just awesome for high RPM, but there is no plenum volume to speak of. Large plenum can also create problems with laminar air flow on N/A but that may not be a big issue under boost. Lots of ins, lots of outs.

Captain Bondo · 06-27-2012, 02:05 PM

Quote:

Originally Posted by PCH

And what about ITB's? They are just awesome for high RPM, but there is no plenum volume to speak of.

Huh? The plenum is whatever you make it to be.

PCH · 06-27-2012, 02:12 PM

HansW · 06-27-2012, 04:36 PM

Hi
VV pete wrote:
>> The ONLY limitation of K-Jet as placed into Volvo's is the in-ability to adjust the control pressure to accomodate new fuel demands from performance mods. And we're talking about the Warm Up Regulator.<<
This is overcome by using a Porsche 924 turbo regulator (saab 900 turbo had the same). In principle it is the same like the VW regulator with the vacum driven fuel enrichment, only, that when there is pressure in the manifold, the regulator lowers the regulator pressure even more allowing for the extra fuel needed. Other than that the normal b230E K-jet is well oversized to deal with a turbo charged situation. the system pressure can be increased 10% as well giving it a bit of extra fuel.

dl242gt · 06-27-2012, 06:20 PM

The B21ET engine used control pressure regulator fuel enrichment and in stock non intercooler or intercooled form made more power than the US B21FT.

PCH · 06-27-2012, 06:46 PM

Quote:

Originally Posted by HansW

Hi
VV pete wrote:
>> The ONLY limitation of K-Jet as placed into Volvo's is the in-ability to adjust the control pressure to accomodate new fuel demands from performance mods. And we're talking about the Warm Up Regulator.<<
This is overcome by using a Porsche 924 turbo regulator (saab 900 turbo had the same). In principle it is the same like the VW regulator with the vacum driven fuel enrichment, only, that when there is pressure in the manifold, the regulator lowers the regulator pressure even more allowing for the extra fuel needed. Other than that the normal b230E K-jet is well oversized to deal with a turbo charged situation. the system pressure can be increased 10% as well giving it a bit of extra fuel.

Some CPRs can be tweaked by getting to the factory calibration screw to lower the control pressure:

vvpete · 06-28-2012, 02:16 PM

The simple fixes like positive pressure enrichement driving a WUR or adding the cold start valve driven by MAP sensor just give more fuel, which depending on several factors like rpm, engine load, and air flow can put the engine, although temporarilly, into a excessively rich A/F ratio. There is no optimum A/F curve like there is provided from an air flow plate and bowl designed to increase fuel proportionately in the K-Jet.
You really need to select the appropriate bowl and plate diameter to match your fuel curve after you determine the amount of enrichment you need.
Example: If you go with a P924 WUR and add to your stock B21F non-Lambda bowl you will get overenrichment nearly throughout the rpm range. This is also true if you adjust the WUR control presssure as seen below. The bowl and A/F plate can adjust out to a point. but if the enrichemnt is more than about -2 psi over stock then you need to look for a bowl with more air flow. Bowls to look for are:
B21FT/B28F
B23E
B21ET
B23ET
MB 6.5
Delorean B28F

Once you get into the 2-1 fuel lines per injector, the MB bowl is about the biggest there is availble, also the one chosen for the Volvo ETC car, had the MB bowl upside down, and a TT 16v.The B21FT /B28F/Delorean is a start, but the B23E bowl is bigger and has a steeper slope as the plate is lifted, so it is a better choice.

The WUR from a 260 or DeLorean is a good choice, too, but a variable valve that changes control pressure as manifold pressure changes is the way to go.

06-27-2012, 03:03 AM	#32
242 glt Board Member Join Date: Dec 2009 Location: Over where mopars and volvos are parked.	Still have some q about your pics, umm the b20 injectors how are they held in? Also what is a l.h 1 intake? I do know there is a late and early style b23/ b230 intake. Also the tb in your pic is upside down? whats up with that? __________________ No more turbo. 1985 volvo 244dl 1988 volvo dl 1967 Plymouth GTX HT, 4spd, 360, 391 posi, daily driver. 1964 Plymouth Valiant 2d post, Welded frame conn, torque boxes, super slant 6 project, now daily driver.

06-27-2012, 02:12 PM	#40
PCH Board Member Join Date: Oct 2008 Location: SoCal	OK.

06-27-2012, 04:36 PM	#41
HansW Board Member Join Date: Jul 2004 Location: Ireland	Hi VV pete wrote: >> The ONLY limitation of K-Jet as placed into Volvo's is the in-ability to adjust the control pressure to accomodate new fuel demands from performance mods. And we're talking about the Warm Up Regulator.<< This is overcome by using a Porsche 924 turbo regulator (saab 900 turbo had the same). In principle it is the same like the VW regulator with the vacum driven fuel enrichment, only, that when there is pressure in the manifold, the regulator lowers the regulator pressure even more allowing for the extra fuel needed. Other than that the normal b230E K-jet is well oversized to deal with a turbo charged situation. the system pressure can be increased 10% as well giving it a bit of extra fuel. __________________ 940 classic Cd 1997 B230FT / M90L 531 head planed, ported, v-cam Mls 0.35, 1041 axle 3.74, M90 15G at 0,65 bar 3" turbo back JT-superflow 3" Amm. + 42lbs injectors STONI chips in 984 ecu and 167 EZK Bosch WR5 DC+ (+15)

06-27-2012, 06:20 PM	#42
dl242gt Can play the blues Join Date: Jun 2002 Location: S NJ, a suburb of Phila.	The B21ET engine used control pressure regulator fuel enrichment and in stock non intercooler or intercooled form made more power than the US B21FT. __________________ Dave, 1982 242 turbo. MVP coilover front and rear suspension. Bilstein HD. IPD 25/25 bars. 3" MVP exhaust. Cosworth Sierra hot side T3 .48 with upgraded stock .42 compressor. Ported 90+.True Track diff. Flat hood 1979 front grill Ecode park/turn lights with H4 Hella. 321k miles. Had it since 1995. 1993 245 Classic, 340k miles, enem V15. Genuine Volvo stock over the axle exhaust.

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06-26-2012, 01:30 PM	#26
PCH Board Member Join Date: Oct 2008 Location: SoCal	NA B21F manifold was designed for low end torque and had some issues with flow on #1 and #4 cyl. Overall flow was better than 21FT but of all manifolds available to me for testing back then the LH1 was the winner, that's why i suggested it.

06-26-2012, 02:21 PM	#29
PCH Board Member Join Date: Oct 2008 Location: SoCal	That plenum volume had a lot to do with needing to keep the air meter plate steady. Especially since it was so close to the throttle. But yeah, some are better than others depending what you want from them. Any manifold and any cam works best at only one specific range- the rest is the trade off.

06-26-2012, 10:44 PM	#30
Volvo69 Board Member Join Date: Sep 2010 Location: Grass valley	I like the relocation of the kjet. Never thought of that.

06-27-2012, 12:10 AM	#31
PCH Board Member Join Date: Oct 2008 Location: SoCal	The 21F manifold was killing the high RPM potential of the K-cam, so it had to be done to experiment with something different.

06-27-2012, 03:08 AM	#33
242 glt Board Member Join Date: Dec 2009 Location: Over where mopars and volvos are parked.	Also just for the recored im not talking about the b21ft intake im talking about b23/b230, someone mentioned the b21f intake as a upgrade and i think that would flow good, i have one, just not the correct linkage for it..

06-27-2012, 12:05 PM	#34
PCH Board Member Join Date: Oct 2008 Location: SoCal	1981,1982 LH1.0 Intake had TB mounted like that from the factory, so it's not upside down. And the injectors are the usual kjet, just had to improvise the mounting.

06-27-2012, 01:19 PM	#36
PCH Board Member Join Date: Oct 2008 Location: SoCal	The B21F manifold did the best job of providing torque (long straight runners) and smoothing out the vacuum (large plenum). Running K cam with its overlap specs required that. But just from looking at the B21F manifold its obvious that its not high RPM friendly.

06-27-2012, 01:27 PM	#37
doucheNozzle Emerged as Ugly Butterfly Join Date: Feb 2009 Location: Cub Scout Camp, CA 93405	A large plenum is for high RPM.

06-27-2012, 01:59 PM	#38
PCH Board Member Join Date: Oct 2008 Location: SoCal	Yes and no. It all works together and affects different things depending on RPM, load, boost, etc. B21F manifold is a good upgrade over the original Turbo one in part because of its large plenum. But it was not developed for turbo application originally. And what about ITB's? They are just awesome for high RPM, but there is no plenum volume to speak of. Large plenum can also create problems with laminar air flow on N/A but that may not be a big issue under boost. Lots of ins, lots of outs.

06-28-2012, 02:16 PM	#44
vvpete Board Member Join Date: Feb 2005 Location: Somewhere In-Between	The simple fixes like positive pressure enrichement driving a WUR or adding the cold start valve driven by MAP sensor just give more fuel, which depending on several factors like rpm, engine load, and air flow can put the engine, although temporarilly, into a excessively rich A/F ratio. There is no optimum A/F curve like there is provided from an air flow plate and bowl designed to increase fuel proportionately in the K-Jet. You really need to select the appropriate bowl and plate diameter to match your fuel curve after you determine the amount of enrichment you need. Example: If you go with a P924 WUR and add to your stock B21F non-Lambda bowl you will get overenrichment nearly throughout the rpm range. This is also true if you adjust the WUR control presssure as seen below. The bowl and A/F plate can adjust out to a point. but if the enrichemnt is more than about -2 psi over stock then you need to look for a bowl with more air flow. Bowls to look for are: B21FT/B28F B23E B21ET B23ET MB 6.5 Delorean B28F Once you get into the 2-1 fuel lines per injector, the MB bowl is about the biggest there is availble, also the one chosen for the Volvo ETC car, had the MB bowl upside down, and a TT 16v.The B21FT /B28F/Delorean is a start, but the B23E bowl is bigger and has a steeper slope as the plate is lifted, so it is a better choice. The WUR from a 260 or DeLorean is a good choice, too, but a variable valve that changes control pressure as manifold pressure changes is the way to go.