recommendations for vems or something else

[GintsK]

Regarding 20VT and knock.
In my opinion there is very few non-knocking engines in this CR range. 20VT is one of these few. You can go close to MBT with no knock at 1.6...1.8bar boost levels. For many [other] engines with lower CR such boost levels mean very retarded, piggy rich, very hot EGTs etc. For those engines knock control can provide really notable difference. Then you can feel each half degree added advance even with no measuring.

[A80Avant]

Regarding 20VT and knock.
In my opinion there is very few non-knocking engines in this CR range. 20VT is one of these few. You can go close to MBT with no knock at 1.6...1.8bar boost levels. For many engines with lower CR such boost levels mean very retarded, piggy rich, very hot EGTs etc. For those engines knock control can provide really notable difference. Then you can feel each half degree added advance even with no measuring.

Sure, that is correct but we have to say that if you can produce more torque on a combination of lower timing and more boost rather than less boost and more timing then it is not a problem going far off the MBT.
Example: if you get more torque with 13deg and 2 bar boost while also keeping 0.80 lambda, then is rather have that than 1.6bar boost and 18deg timing.

Or the opposite if it proves to produce more torque. But so far I have seen that the combination of more boost and less timing esp. At lower revs seems to give better results.

How much boost you keep towards the red line is all up to the setup itself.

[dgacampbell]

Out of interest you say Tatech is the be all and end all, it is however £2500.

What does it do that the £1000 + vat Link Extreme doesn't as that seems like a LOT of ecu for the money.

Features can be seen here :

http://www.linkecu.com/products/engine-management-ecus/g4-xtreme

I know people that tune with that ecu and swear by it like Dimitri does for Moronic

NOT a dig at anyone btw, I don't map engines although I know many that do so I have seen cheap ecu's work perfectly to a Pectel that not even someone at Pectel had heard of

My understanding and usual advice to people looking to buy a ecu is only by what your TUNER feels comfortable with mapping, that doesn't make certain ecus inferior, its just personal taste.

People are drawn in by using super trick race bred ecus but in all honesty do you need a pit lane speed limiter on your track car, or road car? I doubt it. I find it hard to believe that a suitable ecu has to run to so much money.

If closed loop knock control is the answer to all our problems what is your opinion on the Link Prj ? don't baffle me with science, just a opinion.

Anyone any words of wisdom about this stuff yet, have been reading this thread, a bit of useful info between bitching lol
I am very interested in this, tho don't know much, was looking as for my own car a N/A 2.3 NG engine (yes for reasons best known to myself) actually so i may at some stage if i get round to it, convert to multipoint lpg system.

The above all looks good until it comes to knock control...... £700 odd for the ability on top of the price of the ecus?
I was looking at megasquirt 2, and am told it can use my cars own knock sensor and controller....... (by someone selling ms stuff)
I know in my car being non turbo it may not be important, but it's there standard, and i would like to keep the safety of it....

Dan.

[Jamo]

Regarding 20VT and knock.
In my opinion there is very few non-knocking engines in this CR range. 20VT is one of these few. You can go close to MBT with no knock at 1.6...1.8bar boost levels. For many engines with lower CR such boost levels mean very retarded, piggy rich, very hot EGTs etc. For those engines knock control can provide really notable difference. Then you can feel each half degree added advance even with no measuring.

Just trying to get my head around this one, lower CR engine would be retarded and hot egt? do you mean higer cr as surely the lower cr can run more timing and be closer to MBT without being knock retarded?

[Jonnybravo]

Anyone any words of wisdom about this stuff yet, have been reading this thread, a bit of useful info between bitching lol
I am very interested in this, tho don't know much, was looking as for my own car a N/A 2.3 NG engine (yes for reasons best known to myself) actually so i may at some stage if i get round to it, convert to multipoint lpg system.

The above all looks good until it comes to knock control...... £700 odd for the ability on top of the price of the ecus?
I was looking at megasquirt 2, and am told it can use my cars own knock sensor and controller....... (by someone selling ms stuff)
I know in my car being non turbo it may not be important, but it's there standard, and i would like to keep the safety of it....

Dan.

I've seen some very powerful NA engines, none that ever used knock control and mapped by some of the best in the business.

Although basic the MBE 967 seems to be a well used ecu on the normal throttle body conversions, Emerald is full of features but I'm told is a pain to map on the road as it was designed around being used on the rollers.

For what you want I would look at the M tech V4, its a pre built Megasquirt that I know a few people are speaking highly of, its probably cheaper than the MBE as well tbh.

[dgacampbell]

I've seen some very powerful NA engines, none that ever used knock control and mapped by some of the best in the business.

Although basic the MBE 967 seems to be a well used ecu on the normal throttle body conversions, Emerald is full of features but I'm told is a pain to map on the road as it was designed around being used on the rollers.

For what you want I would look at the M tech V4, its a pre built Megasquirt that I know a few people are speaking highly of, its probably cheaper than the MBE as well tbh.

Thanks for reply m8, can you point me in the direction where i can go look at the above? It's ok found the site! Looks very Promising!

TIA
Dan.

[Jonnybravo]

Matt @ Mtech is very helpful, they designed the ecu themselves but it uses the MS mapping software which I'm told is very easy to get on with.

I was going to use the V4 on my Honda S2000 engine so I'm sure its more than upto the job for what you want

[prj]

If closed loop knock control is the answer to all our problems what is your opinion on the Link Prj ? don't baffle me with science, just a opinion.

I just map the stock Motronic, which had cylinder-selective closed loop knock control in the 1980's

Use whatever you want.

[GintsK]

Just trying to get my head around this one, lower CR engine would be retarded and hot egt? do you mean higer cr as surely the lower cr can run more timing and be closer to MBT without being knock retarded?

For example Subarus, or Nissan stuff of same era. With CR around 1:8...8.5. And what - them knocks significant earlier [boost-wise] than 20VT. That is what I meant.
20VT has 1:9.3 and it can be boosted unbelievable heavily [for this CR] with no knock limitation.

[dgacampbell]

Thanks m8,
I will email them here for some more information, will be some time next year before i start, was hoping to be started by now, but money being the hold up as usual lol
Looks like only really the wideband lambda needed on top of that kit, unless i read wrong there is a built in controller? will find out in email for sure!
That and the custom fuel rail, as i'm told the NG injectors are positioned diferently in the manifold from the rest of the 5 pots!
Everything else like injectors, tps can be got from the scrapyard!

[prj]

For example Subarus, or Nissan stuff of same era. With CR around 1:8...8.5. And what - them knocks significant earlier [boost-wise] than 20VT. That is what I meant.
20VT has 1:9.3 and it can be boosted unbelievable heavily [for this CR] with no knock limitation.

This is mostly because aan does not flow compared to those engines and to reach comparable cylinder charge you have to run much more boost.

[GintsK]

Suabru? EJ20? Flows? Are you joking? Overall flow of this engine is comparable with 10VT overall flow. Nissan SSR20DET has comparable volumetric efficiency with 20VT (remeber 20VT has good valve area/displacement), but as soon you go over 1bar boost you have knock...
Same effect has many engines with restricted flow. Like G60 w/ turbo, 10VT, BMW M20 w/ turbo...
In my opinion it definitely somewhat in combustion chamber design what allows boost up 20VT with no knock.

Gints

[driftin jo]

The EJ 20 is very over square and this makes it more prone to knock than the 20vt

[GintsK]

Yes, it is closer.
But I want to put 20VT more like exception here.

[driftin jo]

Yes, it is closer.
But I want to put 20VT more like exception here.

I don't understand, what do you mean by 'it is closer' ?

What I meant was the EJ20 is very over square as in 92mm bore 75mm stroke.

The Nissan SR20DET is dead square at 86mm bore and 86mm stroke.

The Audi 20vt is under square at 81mm bore and 86.4 stroke.