Staying With LH2.4 In A +T Project

[SteveMD]

I'm going this route soon and want to document how to plug n' play LH2.4 turbo computers (hardly a new concept here) into the LH2.4 NA harness. Based on reading some +t sagas on TB, it seems there is/are one or more wiring differences. I am documenting that here and inviting TB members to chime in with anything I might have missed.

Wiring differences:
TPS: Pin 3 of the NA TPS (red/white wire?) is not used with the turbo ECU. Early LH2.4 turbo ECU's don't care/ignore input from that pin but later ECU's may be upset about input from the pin. Solution: disable contact between that pin and the harness? Use turbo TPS?

Injector Ish: Since we are going to need bigger injectors anyway, why not opt for modern high-rez injectors with better spray patterns and support for up to 300hp. No resistors needed and direct fit. http://www.racetronix.com/L107FM.html $55 each though, rather spendy. Boris uses them.
Reconditioned injectors of all types, good prices: http://www.injectors4u.com/injector_prices.htm

ECU Coolant Temp Sensor: If using a '92 or later ECU, you should use the '92 or later temp sensor as it is smarter/faster and the later ECU's are more dependent on intelligent and quick input from that temp sensor.
The '92+ sensor is now the standard replacement sensor for all LH2.4

EFan control: If going efan via turbo ECU, you should switch to the '92 or later temp sensor as it seems to cycle faster, managing engine temp better. http://forums.turbobricks.com/showthread.php?t=117616

That's all I am aware of so far. Sounds too easy? Let me know and I will update this post.

[Homer]

Uhh the TPS wiring is the same. Just leave it. The extra wire doesn't affect anything.
There isn't much to do besides plug the computers in and start the car.

[Lord Tentacle]

Originally Posted by MrSteve

I'm going this route soon and want to document how to plug n' play LH2.4 turbo computers (hardly a new concept here) into the LH2.4 NA harness. Based on reading some +t sagas on TB, it seems there is/are one or more wiring differences. I am documenting that here and inviting TB members to chime in with anything I might have missed.

its easier than u think

Originally Posted by MrSteve

Wiring differences:
TPS: Pin 3 of the TPS (red/white wire) is not used with the turbo ECU. I may be wrong but don't the 2 remaining wires (for closed throttle and WOT) have to be reversed in the plug on the harness?

Any other wiring differences we should know?

cut wire #3 comming out of the TPS connector, NO other changes need be made
though you dont have to do this if you dont want to

Originally Posted by MrSteve

Injector Ish: Since we are going to need bigger injectors anyway, why not opt for modern high-rez injectors with better spray patterns and support for up to 300hp. No resistors needed and direct fit. http://www.racetronix.com/L107FM.html $55 each though, rather spendy. Boris uses them.
Reconditioned injectors of all types, good prices: http://www.injectors4u.com/injector_prices.htm

with the stock AMM your limited to a 42lb injector with freds chips, things bigger than that give iffy results, with the 3" 012 AMM 55-75lb injectors seam to work just fine

Originally Posted by MrSteve

EFan control: If going efan via turbo ECU, you should switch to the '92 or later temp sensor as it seems to cycle faster, managing engine temp better. http://forums.turbobricks.com/showthread.php?t=117616

the 740/940 ecu set the fan to come on at crap temperatures...
the low comes on at 212F after the thermostat has been fully open for a while and the high speed comes on at 240F when the engine is ready to boil over....
stick a saab t housing in the lower radiator hose with a 160F switch controlling the low speed
it works great and has had no issues keeping the engine temp absolutly flat at the temp the thermostat wants it to be.

you can even get 3 way thermostatic switches that screw into the saab housing to give you the choice of off/180/210 so it controlls the fan at both low and high speed

the low/high speed should also be controlled with the AC sensors if your going to keep them

[500dollar744ti]

yeah LH2.4 is the easiest +T evar.

[Nick]

Originally Posted by Homer

Uhh the TPS wiring is the same. Just leave it. The extra wire doesn't affect anything.
There isn't much to do besides plug the computers in and start the car.

+1, especially if you use those injectors you're talking about. Might need to run a bigger AMM tho if you go too much bigger than stock.

[SteveMD]

Cool, especially the LH2.4 efan info. I have heard stories here that people are finding the late lh2.4 turbo bores rather worn from the high temps LH2.4 lets them get up to before triggering the efan.

[JW240]

I left the WOT signal in place, dunno if it really affects something. if i ever get past the stage of running turbo injection/ignition i'll remove the wire. maybe it will act up with other ecu's though (i have 962/967 LH and 219 EZK)

Originally Posted by MrSteve

Cool, especially the LH2.4 efan info. I have heard stories here that people are finding the late lh2.4 turbo bores rather worn from the high temps LH2.4 lets them get up to before triggering the efan.

my efan control works bad but thats with the 17 year old temp sensor that reacts a lot slower.

i would replace the sensor anyway since it can/should help milage if yo replace it for a new one that isnt worn out. then try if the efan works good for your setup.
even my 1995 B230FK (low pressure turbo) with mechanical fan showed wear in the bore, i blame it on bad oil etc.

Try to get the newer white label ecu's. the later the better.

[badvlvo]

WHat are the pros and cons to putting the AMM in the cold side pipe? I know of people who have done it but I have not.

[Hodginsa]

Boost kills AMMs. Im pretty sure that was the consensus awhile ago... And I also think, even though its called the "cold side" Im pretty sure the air is still a lot hotter than the air in the atmosphere, and AMMs don't take well to heat. I think I fried an AMM because I was stupid and had my cone filter too close(and behind sorta) to my rad. Then again some people have gotten it to work.
Those are cons.

A pro would be you could have a BOV(instead of the CBV) before the AMM and not have a crazy rich spike every time you lift off of the gas.

[740Weapon]

re the two above posts, boost might kill AMMs no matter what, however at the very least a good IC would be very required if your going to think about it.

ICs are VERY good filters for oil and crap (from personal observation, maybe not the board concensus on the subject). so its not like being downstream of the PCV and turbo should kill an AMM all that quick.

another hard fact: an AMM is like $25 at a junk yard. then again, the wire required to extend the harness to the other side of the car is less than $25.

[The Ironswede]

Originally Posted by crazy0000

A pro would be you could have a BOV(instead of the CBV) before the AMM and not have a crazy rich spike every time you lift off of the gas.

So you cant run a BOV on the cold side pipe in front of the throttle body? Isnt that where everyone puts one? I didn’t know it would make it spike rich.

[Hodginsa]

Well think of it like this. People put up with the rich spike(Or they run MS). You have to remember the every bit of air your turbo sucks up is read by the AMM because its before the turbo, if it reads that you sucked a certain amount of air it expects that air to reach the engine . When you "blow off" your air, the air your engine is expecting to get is not getting it anymore. Hence why there will be more fuel then there is supposed to be- Reads more air puts more fuel, reads more air but air doesnt get air then its just more fuel (E.g. rich spike). This is why volvos use CBVs because it returns the boosted air(or bypasses) to the system, not losing any.

[The Ironswede]

Originally Posted by crazy0000

Well think of it like this. People put up with the rich spike(Or they run MS). You have to remember the every bit of air your turbo sucks up is read by the AMM because its before the turbo, if it reads that you sucked a certain amount of air it expects that air to reach the engine . When you "blow off" your air, the air your engine is expecting to get is not getting it anymore. Hence why there will be more fuel then there is supposed to be- Reads more air puts more fuel, reads more air but air doesnt get air then its just more fuel (E.g. rich spike). This is why volvos use CBVs because it returns the boosted air(or bypasses) to the system, not losing any.

That is such a great explanation. Thank you! I don’t think my turbo has the CBV. Will I need one to at least get it running “ok”? It looks like the only thing that came with my turbo and piping is….the turbo and piping.

[HonestJhon]

i thought someone logged the air temps and how effective a good intercooler was at getting the boost air close to ambient air temps?

also, they DO make blow-through mass air flow sensors which are able to be run in boost tubes, reading the air that actually makes it to the engine (bov or not)... whether or not one will work for our cars STOCK? i doubt it. with MS, probably.

[Hodginsa]

Originally Posted by The Ironswede

That is such a great explanation. Thank you! I don’t think my turbo has the CBV. Will I need one to at least get it running “ok”? It looks like the only thing that came with my turbo and piping is….the turbo and piping.

What year of car did it come out of? The later models the CBV is built right into the turbo. So it will have nothing to do with the piping. Its only I think -90 when they had the CBV mounted to the engine with extra piping to reroute the air.

I wouldn't really suggest having not CBV, even a BOV would do better than not having anything. Because all of that pressure when you let off the gas gets pushed back into the turbo. I just don't think it would be good. But it might just increase your turbo lag between shifts.

I think there was a video on here, of a members 240? It didn't have a CBV or anything when he first got it running, made a really weird noise every time he shifted because of the turbo fighting the pressure of the boost. Anyway it was funny, can anyone post it on here?

Originally Posted by MrSteve

EFan control: If going efan via turbo ECU, you should switch to the '92 or later temp sensor as it seems to cycle faster, managing engine temp better. http://forums.turbobricks.com/showthread.php?t=117616

Originally Posted by JW240

my efan control works bad but thats with the 17 year old temp sensor that reacts a lot slower.

i would replace the sensor anyway since it can/should help milage if yo replace it for a new one that isnt worn out. then try if the efan works good for your setup.
even my 1995 B230FK (low pressure turbo) with mechanical fan showed wear in the bore, i blame it on bad oil etc.

Try to get the newer white label ecu's. the later the better.

If you are using an ECU that is newer than 1992 you will have to use the 92+ temp sensor od the car will not run good (in comparison) since the newer ECU's have a somewhat different fuel calculation that relies more on the engine temp.

Originally Posted by Homer

Uhh the TPS wiring is the same. Just leave it. The extra wire doesn't affect anything.
There isn't much to do besides plug the computers in and start the car.

Originally Posted by JW240

I left the WOT signal in place, dunno if it really affects something. if i ever get past the stage of running turbo injection/ignition i'll remove the wire. maybe it will act up with other ecu's though (i have 962/967 LH and 219 EZK)

Some ECU's will act up. I don't know which ones, but I guess that only the newest ECU's are affected.

[Lord Tentacle]

Originally Posted by frpe82

If you are using an ECU that is newer than 1992 you will have to use the 92+ temp sensor od the car will not run good (in comparison) since the newer ECU's have a somewhat different fuel calculation that relies more on the engine temp.

u know... that would have been nice to know... as i never did change mine from the origional 1991 sensor even when running the 984ecu.....

[Renny_D]

Originally Posted by 740Weapon

re the two above posts, boost might kill AMMs no matter what, however at the very least a good IC would be very required if your going to think about it.

ICs are VERY good filters for oil and crap (from personal observation, maybe not the board concensus on the subject). so its not like being downstream of the PCV and turbo should kill an AMM all that quick.

another hard fact: an AMM is like $25 at a junk yard. then again, the wire required to extend the harness to the other side of the car is less than $25.

Where does one find this mythical extension wire and on what cars? I've been wanting to do this forever - my biggest reason is there is a tip in lean, less with freds chips, but still there. I think getting the amm as close to the throttle plate as possible would be a big advantage where that is concerned. Also if a hose blows off the car still runs. I think it will just be doing the regular cleanings of the amm that will be more necessary.

Thanks

[740Weapon]

Originally Posted by Renny_D

Where does one find this mythical extension wire and on what cars? I've been wanting to do this forever - my biggest reason is there is a tip in lean, less with freds chips, but still there. I think getting the amm as close to the throttle plate as possible would be a big advantage where that is concerned. Also if a hose blows off the car still runs. I think it will just be doing the regular cleanings of the amm that will be more necessary.

Thanks

i think ur thinking about this tip in lean and AMM sesor lag issue with flawed reasoning.
its a programming issue and not a measurement issue.

air is conserved throughout the intake system right?

right.

so assuming the conserved air can lead and lag throughout the system (which i dont believe or atleast feel is completely negligable) what do you think got measured first:

1. the air that the turbo sucked in to compress the system?

or

2. that air once it made its way to the throttle plate?

IMO the sensor location cant possibly matter on that issue. and if it did its probably better to measure pre-turbo so the ECU gets the most warning time possible that the motor is about to get a very large dose of air.

air has to be sucked in and compressed and intercooled before it reaches the throttle plates right? so perhaps a measureable amount of time passes between sucking the mass of air and ingesting the mass of air.

[badvlvo]

Originally Posted by crazy0000

Boost kills AMMs. Im pretty sure that was the consensus awhile ago... And I also think, even though its called the "cold side" Im pretty sure the air is still a lot hotter than the air in the atmosphere, and AMMs don't take well to heat. I think I fried an AMM because I was stupid and had my cone filter too close(and behind sorta) to my rad. Then again some people have gotten it to work.
Those are cons.

A pro would be you could have a BOV(instead of the CBV) before the AMM and not have a crazy rich spike every time you lift off of the gas.

i just wanted to throw this around to see what kind of results people have experienced.

The air mass measurement is more accurate for what is going into the engine on the cold side but the fuel tables already compensate for that. I think it would cause it engine to run rich on boost but might help at higher boost levels than stock.

Either way, I won't be doing that to any of my cars as I am sure 15-20psi would hurt the AMM.

Originally Posted by Tiebird

u know... that would have been nice to know... as i never did change mine from the origional 1991 sensor even when running the 984ecu.....

Hmmm... I did not think of it at the time when you bought the chips/ECU.

And yeah, the 92+ sensor is much quicker and it will also fluctuate quickly with the temparature change and never bee semi-stable at a fixed value (well... fixed range) like the pre-92 sensor. The newer ECU's rely on the temp sensor more to make the fuel calcualtions more exact. Not like the earlier ECU's that only cares about whether the engine is cold, at operating temperature, or too hot.

[Homer]

Originally Posted by frpe82

Hmmm... I did not think of it at the time when you bought the chips/ECU.

And yeah, the 92+ sensor is much quicker and it will also fluctuate quickly with the temparature change and never bee semi-stable at a fixed value (well... fixed range) like the pre-92 sensor. The newer ECU's rely on the temp sensor more to make the fuel calcualtions more exact. Not like the earlier ECU's that only cares about whether the engine is cold, at operating temperature, or too hot.

Looking at part numbers for a 1995 940 Turbo and a 1990 240 NA. The sensor part number is the exact same. I'm switching to a 967 ecu from my 563 that died. (+T) I replaced my temp sensor last april. I assume that I will be ok?

[SteveMD]

Originally Posted by Homer

Looking at part numbers for a 1995 940 Turbo and a 1990 240 NA. The sensor part number is the exact same. I'm switching to a 967 ecu from my 563 that died. (+T) I replaced my temp sensor last april. I assume that I will be ok?

Are you looking at the actual sensor from your '90 or looking online/at VADIS? I wonder if Volvo made the '92 and later sensor the standard replacement for all LH2.4 so that's why the PN's are the same today. Back in '90 maybe the PN was different and the sensor the dumber/slower one.

[Homer]

Originally Posted by MrSteve

Are you looking at the actual sensor from your '90 or looking online/at VADIS? I wonder if Volvo made the '92 and later sensor the standard replacement for all LH2.4 so that's why the PN's are the same today. Back in '90 maybe the PN was different and the sensor the dumber/slower one.

Online.
Knowing Volvo it was probably superseded.
Edit: It was.
1346030 (Bosch 0280-130-032)
Both are listed as the replacement sensor for my car and 95 turbos.