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B230F LH3.1 budget na build

sloopy

2-digit whp
Joined
May 25, 2020
Location
Dallas, Texas
I have a 1992 240 wagon with an M47 and LH3.1

I am seeking advice on modifying and tuning a B230F

My goal is to shift the power band up and make the car more lively. I don't want to open up the engine except for maybe some head work if it's necessary. I want to do a 4-2-1 wrapped header into a sport exhaust system and put a cam in at a minimum.

I've read a lot about the H cam and it seems to be my ideal choice since I'm willing to sacrifice low end power. The RSI cam seems awesome, but I don't know how to get one. I'm also wondering if the LH3.1 system will be able to handle these cams.

I have found two headers on the market. The simons header collects into a 2.5" pipe, which I guess you would mate up to a 2.5" exhaust. The KG header collects into 60mm which I guess you would mate up to a 2.25" exhaust. At what point is the 2.25" system going to limit me? Are there going to be any negative effects of going with the 2.5" system?

At what point are injectors and head work necessary?

And at what point does a standalone ecu make sense? I'm fairly skilled in electronics, wiring, and circuit board work.
 
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If I turbocharge it, will I have to go standalone since I have lh3.1?

I really am trying to avoid the complexity of a turbocharger setup.
 
Cam (k cam or vx3 at a minimum) , shaved head and mild porting, premium gas if it pings on regular. That’s about a 20-30hp increase right there.
No need for an exhaust header at that level. They do sound better with a “race” header though.
 
Install an e-fan.

I have a LH 2.4 wiring harness for 240 and it is only 4-wires-to-make-it-run. Add turbo and turbo computers. You will have a FUN daily.
 
I was not really expecting more than a 20hp gain and I would be fine with that. But if it's seriously that easy to turbocharge it then I guess I'll bite...
 
Adding a turbo to the car is pretty easy, but a cam swap and getting the head decked is a whole lot easier. You can also +t the engine later, and then just open up the exhaust side of the chambers to get the compression ratio where you want it.

Point of reference: I'm doing a head right now for a 9:1 turbo build, and the head has been shaved almost .055in.
 
I was in your shoes at one time. I wanted to stay NA and I did for along time. But when I did mods I had turbo in the back of my mind. Finally after a cam, elect. fan, homemade intake, big ex., fuel system upgrade, custom chips. I still wanted more power, so I did +T and man did it wake it up. Your in a rock and hardplace with the 3.1. If you plan to keep it for good Id change it over to 2.4.
 
I was in your shoes at one time. I wanted to stay NA and I did for along time. But when I did mods I had turbo in the back of my mind. Finally after a cam, elect. fan, homemade intake, big ex., fuel system upgrade, custom chips. I still wanted more power, so I did +T and man did it wake it up. Your in a rock and hardplace with the 3.1. If you plan to keep it for good Id change it over to 2.4.

Thanks for the advice. A local guy actually has a turbo car with all the parts so I may end up actually turbocharging it. This is my dd though and reliability is important. I assume I'll need a different MAF. Will my throttle position sensor still work with lh2.4?
 
Mill head AT LEAST 0.040", add (any) cam aside from M, L, T, rip it. If you've got an extra $125 also add Cometic MLS head gasket. All in and not reusing stuff that you shouldn't reuse, you're at maybe $500.
 
Mill head AT LEAST 0.040", add (any) cam aside from M, L, T, rip it. If you've got an extra $125 also add Cometic MLS head gasket. All in and not reusing stuff that you shouldn't reuse, you're at maybe $500.

Thanks yeah this is way cheaper, easier, and mechanically simpler. I forgot to mention two additional motivating factors behind going n/a. One is the small weight savings. But the big thing is heat savings. I live in texas and it gets p dang hot. My plan was to wrap the headers all the way down and out of the engine bay to keep under-hood temps down and keep my rubber and plastics in shape for longer.
 
Shoestring, I saw you talking about headers in another thread. Which header did you end up running? I'm trying to decide between 2.25" exhaust and header or 2.5". I'm planning on doing a cam (K, H, or perhaps something more agressive) and some basic head work. I'm also interested in going standalone since I would like to learn more about tuning and have built some pretty good wire harnesses for three formula sae cars.
 
What year intake do you think...

is the best flowing stock intake for the b230. I am also building up my '92 740 and really don't have a budget; though I would like to stay stock and keep it simple.

Seems like I remember my '77 242 n/a would pull like a banshee in 3rd gear up to 70 mph without a problem.

Rick


The moment you decided to go the hard route and not turbo it.

You will also need an intake manifold if you want to see any gains.

Budget and n/a build are conflicting ideals.

Best bang for the buck is turbo.
 
Go with the K instead of the H because it's more readily available and has better "performance" at idle and off idle. Lower emissions, too.

As mentioned by some, a header is not needed at this point. We have a nearly stock exhaust manifold with a custom downpipe into a 2.5" exhaust making over 150whp in the General Leif. You can do some mild port clean-up of the factory exhaust manifold and then have it ceramic coated along with your downpipe, if you really want. It's not necessary, though.
Adding a turbo to the car is pretty easy, but a cam swap and getting the head decked is a whole lot easier. You can also +t the engine later, and then just open up the exhaust side of the chambers to get the compression ratio where you want it.

Point of reference: I'm doing a head right now for a 9:1 turbo build, and the head has been shaved almost .055in.
This. Just be prepared to spend more money than just a decking of the head done if you want a new valve job, new seals and if guides are needed.
This, for sure.
is the best flowing stock intake for the b230. I am also building up my '92 740 and really don't have a budget; though I would like to stay stock and keep it simple.

Seems like I remember my '77 242 n/a would pull like a banshee in 3rd gear up to 70 mph without a problem.
The b21F/k-jet intake manifold flows much better, but doesn't have provisions for injectors. The little B21 in your 242 also likely had shorter gears to go with its B cam that provided the better pull in 3rd gear than your 740's b230 with the M cam.

More later, maybe, but basically read my sticky. LH3.1 is fine and you can tune it yourself with TunerPro and an Ostrich 2.0 from Moates.
 
Thanks for the advice KLR. I know a header isn't needed, but I want one mainly for the sound and for the fact that it will be easier to wrap (I really want to keep heat under the hood down). You say you're running a 2.5" exhaust so I'm assuming that if I go with a 2.5" header and exhaust then I won't be crippling my performance from having pipes which are too big. Although perhaps the header lengths are tuned for a powerband which I won't be able to achieve. At what point is a 2.25" header and exhaust going to limit me? 120whp?

I had read your thread about LH3.1 before, but I have concerns about the lack of replacement MAF sensors for this car. Is there an alternative which can be used in case of failure?

I guess I should have titled the thread "B230F LH3.1 reasonable na build" as I'm not trying to make big power with small money. I just want to get a reasonable amount of power out of the thing without going overboard with modifications and complexity. I really want to keep this car simple and maintainable. It really doesn't bother me that the car is slow as it compensates plentifully in the turns. I really just want to liven the engine up, make it love the revs, and make a nice sound.

Speaking of loving the revs, I'm definitely looking info reducing the rotating mass of the engine. Nothing crazy, but I'm interested in going to electric fan and lightening the flywheel a bit. It does bother me how slow this thing is to rev when I'm downshifting.

And speaking of downshifting, how does everyone manage to heel-toe in this car? The gas pedal is absolutely buried into the firewall. I was thinking I could make a simple spacer which moves the gas pedal closer to me. I searched the forum and I can't find anyone talking about modifying the gas pedal. Has anyone heard of any clever solutions to this?
 
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A header may actually reduce your power and torque, unless it's small. I don't know about the Simons header, but I am a fan of their exhaust systems. A 2.5" exhaust will not hurt your power, but if the header's dimensions are too large, it will. I made over 130whp with a Type 1 header from KGTrimning which is 44.5mm primary and secondary pipe sizes going into a 2.5" exhaust. That header is considered too small for big power through, and I now have 51mm secondary pipes. I haven't been on the dyno in many years, though.

A lack of MAF sensors may be an issue one day, yes. There is no swap that I'm aware of at the moment, but LH3.1 is a better system than 2.4 so I would keep it if possible. I think you could still turbo it if you decided to go that route one day, you'll just need to swap in the turbo ignition computer and then change the mapping in the fuel computer for the larger injectors to match.

Shave the head and get a fresh valve grind(do a basic clean up of the ports if you'd like, open up the chamber a little in places - the more you shave, the more you can open the chamber for better combustion and reduced detonation), slap a K cam in it(maybe advance it 2-4? or to your liking with experimentation), route your warm-up/hot air intake to cold air and get rid of the flap assembly in the airbox and run it. Get an exhaust system from Simons to increase the sound level and rock it. Without doing any engine management tuning, you should still get at least 115whp or a little more if all else is happy. That's coming from the 85-95whp that you might currently have, and if you get an Ostrich and a wideband, you can fine tune some more for additional power and likely better efficiency at high rpm and WOT(wide open throttle). With the ability to tune, you can also get a higher rev limit. You will need to get a higher rev limit for your ignition computer, too, though.

Regarding revs, I hear you. That dog dish flywheel sucks! An e-fan taken from a 940 is a nice upgrade and easy to do, especially if you have a screw in sensor in the top of your radiator. You can get a sensor that has the right temperatures to automatically control it. I originally had a lightened dog dish flywheel, then I went to a 15lb lightened flat flywheel with the holes for the crank sensor added, then I went back to a stock flat flywheel with the holes for the crank sensor as the car because driving in traffic wasn't fun.

I heel-toe fine in my car as is? Try moving your feet a different way. I can't think of how I do it off the top of my head as it's second nature, but I think I just have the left side of my foot on the brake and the right side I pivot down to the gas pedal. Or more my big toe is on the brake and the rest of my foot pivots down to the gas pedal.
 
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Shoestring, I saw you talking about headers in another thread. Which header did you end up running? I'm trying to decide between 2.25" exhaust and header or 2.5". I'm planning on doing a cam (K, H, or perhaps something more agressive) and some basic head work. I'm also interested in going standalone since I would like to learn more about tuning and have built some pretty good wire harnesses for three formula sae cars.

Sorry for the late reply. I'm actually building one specific to my application following Larry Meaux's PipeMax and some David Vizard stuff. My feeling with regard to the off-the-shelf headers are that well, they're kinda big in the pipes, diameter wise.

My kid can probably sell you a tune for this 3.1 at this power level, find him here as redblockpowered. Unless you feel like you really have to do a stand alone.

I also have no problem heel-toeing either my street or race car, and the pedal positions are absolutely stock. How big is your foot? I've a 9.5-10 for reference. Are you applying enough brake? I should clarify that my heel does not come into play, I'm pigeon-toe rolling.
 
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Another comment again for keeping the stock exhaust manifold. Yes, it's hard to wrap, but it works reasonably well and if you're just trying to get a different sound, maybe just the rest of the exhaust system is going to be enough to satisfy you in that area? You can do a ceramic coating if you think underhood temps are getting too high, but they likely won't be because it's all stock and you don't have a turbo...

I don't know what the diameters are of the stock downpipe, but you should at least put a larger merge on the factory downpipe. You may still be able to get around 120whp without a larger downpipe, but I would do it regardless and the rest of the exhaust system in a minimum of 2.25". Or, you can get a complete Simons system without a cat(I like the environment, so you can add one back in) that includes a downpipe and everything back for a reasonable price such as what is linked below. You can get them elsewhere, too, I expect. On the General Leif with the 150whp+ dyno runs, we have a downpipe that is 45mm OD, just like this is.

https://martelius.com/en/products-by-car/volvo-240-non-cat-full-exhaust-system
 
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