How safe is it to modify an unopened engine?

[peadya100]

Im asking this question a little too late as ive already modded a little and had a tune. But im about to have the VF52 installed and another tune.

A friend of mine has an evo and has now blown his engine (broad term i know) for the second time. Most recently after spending 20k and having the engine built with the best of everything.

This has now got me extremely worried about the things i have done, and will soon do to my car.

Does anyone with more engine knowledge than me (not hard to have more than me) have any thoughts or tips?

[Remnofski]

What are you planning on doing? Modding an unopened engine is fine as long as the mods and the tune are correct and the time is taken to ensure safety over power. My previous WRX had 250 hp at the wheels with an unopened engine and could make this day in and day out, but the time was taken to ensure this.

[Robbks]

250hp ATW is only about 185KW ATW, any unopenend 2.0 will make that with a decent exhaust, good intercooler, decent size turbo (VF34, TD05-18G) and about 18psi with a nice tune

185ATW is a piece of cake with a 2.5 and they'll happily make 200ATW all day long with similar mods to above
add a slightly bigger turbo to make sure the car can breathe nicely and make the power delivery smoother.

[peadya100]

Well its currently got 180wkw and with the VF52 should get around 200wkw. But to get to that point its a fair jump in boost pressure. I would have thought that would increase risk.

[peadya100]

What are you planning on doing? Modding an unopened engine is fine as long as the mods and the tune are correct and the time is taken to ensure safety over power. My previous WRX had 250 hp at the wheels with an unopened engine and could make this day in and day out, but the time was taken to ensure this.

What sort of things ensure safety?

[Robbks]

Use a bigger turbo and better intercooler
Less boost, more ignition timing.

How much boost are you running now?

A VF52 is similar in size to a stock TD05-16G that's been around for ever. Great turbo on a 2.0 but the front half just isn;t big enough for a 2.5.

I forget what the size differences are in the new VF turbo's
But for a 2.5 you want something bigger, similar to a a TD05-20G.

The good ting about the TD05 is it has a generous sized exhaust housing, less back pressure, less heat built up, means you get better flow and can run more ignition timing for more power
which is also better for economy and engine safety

have a read of the comparisons here
http://www.iwsti.com/forums/2-5-liter-l ... -dom3.html

[bigBADbenny]

How about monitoring your engine, modded or not, with an afr gauge and a G4 knocklink.

My afr gauge is a AEM 30-4900 failsafe: cuts boost if afr out of range or on overboost condition

Get a tune with a good safety margin as regards afr on boost eg 10.5:1 to 11.0:1, so you're not knocking the moment something goes wrong.

The next thing I'm planning is a (very) functional waterspray to keep things cooler in summer /less heat soak.

And continuing my education on more strategies for keeping my lib running safely.

[Robbks]

BBB, take a look at the Jaycar Smart waterspray controller.
had one on my GT fozz.. great bit of kit and frugal on water use

[bigBADbenny]

Indeed I have its predecessor; the Autospeed version, and now choice of 4L , 5L and 12L tanks.

As soon as I find a reasonably priced G4 Knockink its going in too.

I hope to end up with a lowish powered car that can be driven relatively hard.

So I can use more of the available power more of the time

[jaydece]

All I will say is this:

any mechanical mods (including tunes) will always increase the likely hood of degrading the engines life....we keep pushing it for that little much more power....some engines can naturally handle more? some less....no matter how much logging, gauges, services, fuel, oil, etc etc you do?

driving like miss daisy? yeah that would work.....but then whats the point....

if the engine wants to go bang....it will....we can only mitigate the chances to our favor to a certain extent....but no way promise/guarantee whether built engine or not....but esp on unopened....

I can tell you from experience and knowledge gained.....our oil pickup is one of the 1st mods I would do.....lack of oil in the crank and engine is what kills our engines....especially taking corners, sweeping bends....no tune, gauge, logging is going to help you when the engine starves of oil....

we are all too familiar with the "popped my engine.....end bearing went"....

by factory it is weak and brittle....designed poorly...just look at the killer b website to see what fatal death awaits ...
http://www.killerbmotorsport.com/index_files/OilPickupStory.htm

we mod our cars and gamble away.....some gamble more ....some less...

[bass_straitener]

Good thread Adam..

The answer isn't an easy one however..

Agree with Robb, on don't run too much boost, use more ignition timing. You'll get good gains on an off boost that way.

I only run 18.5 psi max via the tune. Therefore should there be any issues there's a little headroom.

When tuning you're infact reducing the safety margins, so the best off thing to do is install some tools to better manage the risks. In my case a good boost gauge with an alarm which alerts when it's over boosted.

Also an AFR gauge to glance at once in a while or have the info available when going hard to ensure there are no lean spots. Particularly true for OL loop where ECU correction is not available.

A good tuner that adjusts the IAT temp corrections etc to ensure when it's stinking hot your still not running the same timing or boost.

A good tuner will get the temp compensations right and the boost management set properly.

Finally the owner needs to be aware that he's now driving a car with is less risk averse and therefore should warm down the car prior to switching it off etc. I drive the last 3-5kms home in a relaxed manner to allow everything to cool down prior to arriving at home.

It's lots of little things you can do to keep your car safe whilst still enjoying it.

With regards the waterspray, it's a good idea and every little bit helps.

[peadya100]

Sorry for the belated reply.

So basically its in the tuners hands... even if I monitor it, I cant do anything but report it back to the tuner to fix. I do want to be able to monitor things too, but dont want guages everywhere. Would you recommend the vent guage benny?

[dr20t]

If you have access to e85 or eflex then this is one of the best preventative measures for premature death you can do whilst retaining moderate power levels

This does not mean you should push the shit out of the engine just cos you're running ethanol fuel, although you can of course.

But if you only wanted to run say 200 atw, eflex will provide a cooler charge mixture and higher knock threshold

However other prevantative measures need to be taken with ethanol fuel (spark plugs, more regular oil changes) to ensure longevity

I also respectfully disagree with boost vs timing. Boost is better (to a limit) than timing, so long as your cylinder pressures are not rising beyond a dangerous point of lifting heads or inducing pre-ignition

The evidence for this is timing being limited by the fuel type used. Increasing boost increased dynamic compression ratio, which increases volumetric efficiency, whereas increasing timing increases cylinder pressure and charge efficiency to a degree.

Assuming a knock free environment, there comes a point of diminishing return with timing. Not so with boost as boost increases charge density and thus dynamic compression and thus volumetric efficiency

I would much rather more boost than more timing. For multiple reasons in addition to the ones above

To answer the question, 200atw is relatively safe with a good tune. Anything more is pushing it. 250kw atw is doable and has been proven to last 70,000-100,000kms but its definitely the upper limit and running the gauntlet at this level

I'd be happy with 50,000kms on my current setup before having to pull down and rebuild. But that's me others may expect 100,000 or 200,000 but less power

Mick

[peadya100]

Im definitely not against ethanol, its just a 25 min drive from home to get it. I dont want/need more than 200wkw, and from the sounds of it the bigger turbo will be a safer way to achieve that but from what ive seen in other cars with similar mods that takes around 19-20psi. If that boost pressure isnt too high provided MSR maintains safe timing and AFR, then I guess I dont have too much to worry about. I dont thrash my car, but it sounds like I need to pay more attention to letting the car cool down..... and either get some guages or learn how to log.

[bigBADbenny]

Sorry for the belated reply.

So basically its in the tuners hands... even if I monitor it, I cant do anything but report it back to the tuner to fix. I do want to be able to monitor things too, but dont want guages everywhere. Would you recommend the vent guage benny?

Yes the vbg1 GTBoost gauge does it all, inc plots, peak recall, alarm, voltage and afr display & afr plot with compatible uego eg AEM or LC-1.

The idea is that if you're out of range, switch to low boost to protect the engine.
The Aem failsafe can do that automatically.

It's not that versatile as a gauge (no peak hold or recall) so monitor it on the vbg1.