How Much Is Enough?

[davidjt]

Using Elanscan and some fancy hardware/software which is way over my head, we seem to have arrived at a point where we can program our own version of Alan's chip 'live' on a rolling road; my question is, how much boost can we safely run (only occasionally using the max, obviously)
without risking the engine?

Current guestimates are around 1.5 and 260bhp at the flywheel, but any thoughts/input would be much appreciated.

(Already have the brakes + quaife, so this is purely an engine issue.)

Thanks

[Monty]

This is very intersting topic as i would love to have a chip that goes to 1bar or just over. But i don`t think Alan can adjust the fuel cut any higher so it would have to be clipped. I know Alan says that the stock turbo can`t hold 1 bar for long but on Dico`s we`ve found out his has been running at 1.4bar for the last 3 years. IIRC the Impulse lads run alot higher boost than us on a stock system.

Have u gone back to the stock turbo?

[ESM]

The issues are:

1) turbo - it isn't designed to go that high/spin that fast. There will be a significant design margin but 1.5bar - more than twice the designed boost - doesn't seem sensible to me without a turbo revision.

2) map sensor - it only reads up to 1 bar of boost, go beyond that and you are into piggyback fuel controllers, replacement ECUs or a considerably modifed stock chip (big job, requiring considerably more understanding of the ECU code than I have now and the extention of all maps with MAP as a lookup beyond the 1 bar threshold)

3) injectors - they can't deliver enough fuel for much more than 1bar of boost. Mapping to control bigger injectors is another significant ECU modification.

Dico's car was ok at 1.4bar boost for 3 years? Well he will have had an A/F ratio of 13.6:1 at that level of boost thanks to the FCD. You can run that lean if you want - I wouldn't - I know from the tuning session I was involved in there will have been some knock at that level. Its a good thing the knock control works pretty well.

Isuzu guys do it: with stock turbo and injectors????
I agree the engine's engineering is very strong and its capable of handling high boost but the turbo, MAP sensor, injectors and ECU maps have a designed in 1bar ceiling. The best power modded cars (Lotus and Isuzu) address all these things. The rest might get away with it for a time but its Russian roulette. You might want to consider how much the Impulse RS is worth (particularly those modded to 1.4bar with stock gear) compared to the Elan and how much parts cost over in the US.

One of the concerns I have at the moment is that you can MBC/FCD an ESM chipped car and, while its a dumb thing to do, its no worse than a BBR with a stuck wategate. If I release the chip with the modified power enrichment table and someone fits one, unknowingly, to a car with an MBC & FCD then it would seriously stuff up the engine - the mixture could go to 17:1 at high boost. I understand now why Lotus made the mixture so rich - its so even if you jam the wastegate shut, disable the boost limit safety and send it a false intake pressure signal to the ECU the engine can survive. It is to protect it from shitty power mods! I'm really wondering if I should remove that safety by releasing the V5 chip. Especially since many people are fundamentally pretty clueless about what's happening under the bonnet.

[Nige]

I'm really wondering if I should remove that safety by releasing the V5 chip. Especially since many people are fundamentally pretty clueless about what's happening under the bonnet.

That seems a fair statement reading some of the posts here and I also am in full accord with all the other content of your post. I am still toying with the idea of a modified turbo at some stage in the future but recognise that I will need a new MAP sensor, new injectors and a completely remapped ECU (Haltech, piggyback or heavily reworked standard) to do that. It's not just the cost it's also the nagging question of whether anyone has yet done this wholly successfully (Costas seems to be the notable exception) as I have not yet seen a 100% positive report from anyone who has gone down this route.

I say yes please to a V5 because I know exactly what I have on the car at the moment and any optimising of the current power delivery would suit me very well, I'm not necessarily looking for more boost than the .9 bar the everest currently gives, although power is addictive. However, I share your concern about the potential consequences and comeback of someone not following your very clear instructions, an even more strongly phrased disclaimer would have to be in order.

[Dico]

Especially since many people are fundamentally pretty clueless about what's happening under the bonnet.

Me included.
I've only recently found out mines been running that high Its possible its been bodged like that for anything up to 5 years
Not only are you risking damaging your engine etc with high boosts but i've found it pointless anyhow as I just get wheelspin (even with the atb fitted).

[John_W]

I understand now why Lotus made the mixture so rich - its so even if you jam the wastegate shut, disable the boost limit safety and send it a false intake pressure signal to the ECU the engine can survive. It is to protect it from shitty power mods!

And this was in 1989, at the time the USA litigation junkies were just getting into their stride.

I'm really wondering if I should remove that safety by releasing the V5 chip. Especially since many people are fundamentally pretty clueless about what's happening under the bonnet.

And there is the dilemma. But could you live with knowing what might have been and you did not allow the possibilities?

:gray:

John

[Monty]

It's not just the cost it's also the nagging question of whether anyone has yet done this wholly successfully (Costas seems to be the notable exception) as I have not yet seen a 100% positive report from anyone who has gone down this route.

Even Costas will tell u not to go down that route

Must admit since i`ve had the exhaust done i`m alot happier with the performance and glad that the saftey features ares still in place. Look forward to the next chip

[Ashaman]

Just to chime in...and agree (of course) with what Alan said; this is also an area where with stock hardware, more does not equal better.

There are two reasons I say this:

#1, Details on these turbos are sketchy due to variations within the RHB5 family. However, even before I owned an Elan I was part of the TurboFord group, where it was commonly related that 20 PSI was pushing it for the RHB5 they used, and it is significantly larger than the stock Elan unit. Operating out of the efficiency range will heat up the intake charge - and at a point - negate any gains you hoped for with the extra boost. Even worse, this ties into:

#2, The detonation/knock issue (which increases with higher intake temps). If you are running the stock ECU, it will start retarding ignition once detonation occurs. Again, this negates the hoped for gains due to increased boost.

The points where these two occur aren't known precisely, but I feel pretty confident that this would be well within the range. You don't want to keep raising boost only to successfully increase your intake temperature and retard ignition timing. You will make less power and you will increase the risk of damage.

Oh yes, and Nige - I did this a couple years ago...drive the car all day with that setup. Dave M. did it before I did! He used a Apexi AFC & I used the Haltech.

Regarding the uncontrollable wheelspin, that is why you should invest in a quality boost controller. They can regulate the amount of boost delivered in each gear, so you could set say .85 bar for first gear, 1.0 for second, 1.5 for the rest. If you get uncontrollable wheelspin in 4th gear, I would be most impressed

[Nige]

Oh yes, and Nige - I did this a couple years ago...drive the car all day with that setup. Dave M. did it before I did! He used a Apexi AFC & I used the Haltech.

Thanks. It's good to know that it has been done successfully. I'm still unaware of it being done wholly succcesfully over here though, I think Sy still has some issues? I haven't seen an update from Philbo lately. The fully successful mapping of the replacement ECU seems to be the sticking point. I still think I want to go this route in the fullness of time, but only when I'm certain in every detail of exactly what I need to do.

[ESM]

A good bunch of posts.... I hope any ideas of welding up the wastegate, defeating the safeties and hoping for the best have been binned. One bar IS the sensible maximum for essentially stock cars.

I'm going to have to think about how to release the V5. I'm inclined not to make it a full public release. Its imperfect anyway, the dyno we cooked it on was somewhat less than a precision instrument. I believe there is a lot still to be gained from tuning even at the 0.9bar level.

[Sy V]

...well if it's guinea pigs your after Alan, it could replace the prototype chip that I'm still running.

[davidjt]

Er.....thanks!

Hardly expected so much (quality) response so quickly.


Softly, softly it is then. With a frozen shoulder and exhaust issues causing complete soh failure, I'm in no rush anyway; just p'd off I can't make the 'ring trip.

It was never my intention to simply defeat all the safety arrangements and crank up the boost: I may be technically challenged, but I do know its not like turning on a tap. (A friend had a turbo'd clubmans car years ago and his trophy cabinet held seven burned pistons: no silverware. I keep this in mind.)

My turbo has been modified to the same spec as Sy's; I'm inclined to fit the charge cooler first, optimise everything at 1 bar and then think about injectors maybe. (If anyone wants to play with Dave's old hybrid, send me a p.m.)

I wouldn't even think about doing this on my own, but the guys doing the work have a lot of turbo & software expertise, and incidentally were VERY complementary about Elanscan.

Thanks for all the input; I'll post progress reports, as there seems to be so much interest.

[Dico]

Regarding the uncontrollable wheelspin, that is why you should invest in a quality boost controller. They can regulate the amount of boost delivered in each gear, so you could set say .85 bar for first gear, 1.0 for second, 1.5 for the rest. If you get uncontrollable wheelspin in 4th gear, I would be most impressed

Interesting, but i'm hoping that by joining in with the many test pilots that the V5 may solve my problems

BTW David, I think Stef has room for a co pilot. Have you the staying power though? I believe she can handle plenty more than 1 bar!