Maximum boost pressure and boostvalve?

brew1 · **Posted:** Sun Sep 30, 2007 10:42 am

I am considering having my CRD ECU upgraded with a performance tune (not InMotion) and was wondering if anyone knew what the maximum operating boost pressure is for the stock turbo? Anyone?

InMotion tuning informed me their level 2 tune maxes out at 25 psi, just wondering how much room we have to play with before overboost becomes a concern.

Second question. Has anyone here had a boostvalve installed on their CRD? Is so, whereabouts did you install it?

I didn't find anything using the search function, thus the posting.

Thanks!!! - Mark

gmctd · **Posted:** Sun Sep 30, 2007 11:11 am

Diesel engines in stock form do not require a blow-off valve because there is no throttle-plate to suddenly restrict the Boosted intake path - the ECM handles Boost-control very well, and much safer - at 12mhz, response is much faster than a simple spring-loaded pop-off valve

In any engine, Boost pressure is limited by cylinder-head clamping configuration - with this engine, in particular, pressure is limited by the pressure hoses, plastic charge-air cooler, and cylinder-head clamping configuration, which also serves as an attention-getting 'boost valve'

The turbo is Garret VVT\VNT - they will have the maps

brew1 · **Posted:** Sun Sep 30, 2007 10:54 pm

gmctd wrote:

Diesel engines in stock form.

Hit the nail on the head there. This CRD engine will cease to be in stock form shortly.

As previously stated, I am planning to have the ECU programmed with a performance tune that will alter among other things, increase maximum turbo boost pressure.

Its a relatively cheap insurance policy, in case the other things you mention, don't work out exactly as designed.

gmctd · **Posted:** Sun Sep 30, 2007 11:15 pm

Meaning was engine in stock form - which it will be no matter what chip you put in it - you're just hopping up the ECM, with no attention to the engine - studs, copper o-rings, balance, etc - will pay to go cautiously, as noone on this continent has been into one for damage control - at least, none willing to talk about it - post your results along the way

Sir Sam · **Posted:** Mon Oct 01, 2007 12:53 am

in MAF based engine management there is some concern about venting boost pressure because the ECU cannot take into account the lost volumn of air, however I suspect that that is less of the case in this engine because of the MAP based engine management.

DarbyWalters · **Posted:** Mon Oct 01, 2007 1:05 am

With our VNT we don't have a wastegate...the variable vanes basically take care of boost pressures with angles. MrMopr64 mentioned that we would be "good" up to about 340-350 foot pounds with this engine as it sits...after that the head will have problems...Aluminum head with cast iron block...different rates of expansion...ect, ect. Just be careful and upgrade the tranny first...

Sir Sam · **Posted:** Mon Oct 01, 2007 1:09 am

DarbyWalters wrote:

With our VNT we don't have a wastegate...the variable vanes basically take care of boost pressures with angles. MrMopr64 mentioned that we would be "good" up to about 340-350 foot pounds with this engine as it sits...after that the head will have problems...Aluminum head with cast iron block...different rates of expansion...ect, ect. Just be careful and upgrade the tranny first...

I dont buy the differing rates of expansion, there are lots of vehicles with different head materials running like that without issue, I scratch my head to figure whats different about this one.

But like you said, the transmission I think would be the weak link here way before we ran into other restrictions.

But, its a jeep, not a sportscar, and I dont need to tow alot, I dont desire or need massive amount of power and torque, as it is I would rather tune for economy than power.

onthehunt · **Posted:** Mon Oct 01, 2007 2:51 am

Think head gasket and bolts. Aluminum will not take abuse like iron.

Sir Sam · **Posted:** Mon Oct 01, 2007 3:31 am

onthehunt wrote:

Think head gasket and bolts. Aluminum will not take abuse like iron.

Not saying I know what Im talking about with this engine, but in my nissan world of aluminum heads and cast iron blocks 400RW torque doesn't pose a danger to those components in that sense.

gmctd · **Posted:** Mon Oct 01, 2007 4:51 am

I think there will be no problem with the aluminum head if the clamping configuration consists of at least 5 bolts per cylinder - if it's only four, yer screwed - DMax is aluminum 16v head, and they run hi Boost up to 1200hp, properly prepped.

MrMopar is merely indicating stress damage in stock oem form - studs and copper o-rings will seal high cylinder pressure if clamped full circle

Guess what? We got 6-bolts per cylinder, 2 shared, which is standard full-circle pattern for hi output Diesel engines - stud it, o-ring it, and the sky's the limit if the lower-end can keep up - sky will be full of stuff if it can't...............

brew1 · **Posted:** Mon Oct 01, 2007 10:16 am

Great discussion, thanks.

BTW, quite a few of us with modified VW TDI ECU's that run higher boost are using boostvalves. VNT turbos are used on the VW TDI's. Some folks that decided not to run a boostvalve, later wish they did. Turbos are not cheap to replace.

I haven't upgraded my TC or pump yet, haven't had any problems yet. The tuner I'm planning to use has free upgrades, so I will probably start with a tune similar to the InMotion performance tune and upgrade to something a little more aggressive when I can afford the Suncoast TC, Pump, Transgo Shift Kit, Tranny cooler and larger tranny pan.

Larry R. · **Joined:** Sun Jan 21, 2007 1:35 am **Posts:** 92

Hey brew1, who are you having tune your ecm?

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

If you really want to go all out, why not talk to VM Motori? They make stouter heads and other internals for this engine block for marine/industrial purpsoses. If something ever happens to my engine and I had to rebuild, this would be the route I would take.

brew1 · **Posted:** Mon Oct 01, 2007 10:26 pm

Pablo wrote:

If you really want to go all out, why not talk to VM Motori? They make stouter heads and other internals for this engine block for marine/industrial purpsoses. If something ever happens to my engine and I had to rebuild, this would be the route I would take.

Thats a thought, if I had bottomless pockets and an engine that was in need of rebuilding. I don't in either case.

I think the engine has plenty of potential with the existing internals and you would probably need to upgrade the injectors and or turbo to take maximum advantage of this engine. Would be interesting to find out if the existing injectors are up to the task of the added fueling and increased boostpressures. Would almost certainly need that lift pump mod, V6 airbox, free flowing exhaust and possibly an FMIC, just don't know where you would mount one.

I have to remember baby steps, plus its my wifes daily driver.

Tuners name is Jeff Roberts, business name is Rocket Chip. He's pretty well known for tuning VW turbo-diesels, which makes him hard to get a hold of since people are usually lined up for tunes. He did a great job on my Jetta TDI at a GTG here this past April. He tuned at least a dozen TDI's that day, a lot of grinning faces on the drive home.

We have another TDI GTG here later this month. May look a little odd, parking lot full of VW TDI's and one Liberty CRD. I'll let you know if he and I can reach an agreement on tuning the CRD with something slightly more aggressive than the InMotion tune along with deleting the EGR/CEL. I wouldn't consider doing it if he couldn't completely shut down the EGR and delete the associated CEL. He does it all the time on TDI's, so it shouldn't be a problem on the CRD.

If he does the tune, I believe I will be the first Liberty CRD ECU he has tuned. I'll let you know how it turns out.

Mark

onthehunt · **Posted:** Tue Oct 02, 2007 12:07 am

Egr delete would be nice. Isn't Richfield where they built the new Cabela's?

brew1 · **Posted:** Tue Oct 02, 2007 12:36 am

onthehunt wrote:

Egr delete would be nice. Isn't Richfield where they built the new Cabela's?

Yes, great store. Awesome display of North American taxidermy, especially trophy whitetails. I'm just 2 miles down the road from them.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

Sir Sam wrote:

onthehunt wrote:

Think head gasket and bolts. Aluminum will not take abuse like iron.

Not saying I know what Im talking about with this engine, but in my nissan world of aluminum heads and cast iron blocks 400RW torque doesn't pose a danger to those components in that sense.

I wonder how much of a difference in compression exists between the top end of the gasser motors versus the diesels? I have seen videos from the tractor pulls where they weld the head gaskets on the diesel motors and then literally weld a bulkhead around that-- so they can boost 100's of psi through the motor without the head exploding. I don't think the gassers have as much compression or force going on in there as the turbo diesels, but I don't know that much about it either.

curtis · **Posted:** Tue Oct 02, 2007 6:12 am

Pablo wrote:

Sir Sam wrote:

onthehunt wrote:

Think head gasket and bolts. Aluminum will not take abuse like iron.

Not saying I know what Im talking about with this engine, but in my nissan world of aluminum heads and cast iron blocks 400RW torque doesn't pose a danger to those components in that sense.

I wonder how much of a difference in compression exists between the top end of the gasser motors versus the diesels? I have seen videos from the tractor pulls where they weld the head gaskets on the diesel motors and then literally weld a bulkhead around that-- so they can boost 100's of psi through the motor without the head exploding. I don't think the gassers have as much compression or force going on in there as the turbo diesels, but I don't know that much about it either.

Diesel's have well over double the compression of Gas engines.

gmctd · **Posted:** Tue Oct 02, 2007 5:01 pm

More specifically, gassers (patooie!) typically run between 8:1 and 10:1 normally aspirated - turbocharged versions at the lower end of the range - n\a racing engines typically max out at 13:1 with 11:1 and 12:1 being more common - supercharged Top Fuelers down around 6:1

Diesels run 16:1, 17:1 up to 21.1 - the lower range is usually found in Direct Injected natural and turbocharged systems, the higher ranges in the Indirect Injected systems, in both 'charged and naturally aspirated versions.

Diesel components are designed with more mass to endure the additional stresses and harmonics associated with high compression, as well as the additional power available in Diesel fuel - a gallon of Diesel fuel has ~20 greater btu content than a gallon of gasoline.

In the spark-ignited systems, the fuel is trucked in with the intake charge, and must be at a 14:1 ratio mixture for the engine to develop power - rpm and power is controlled by a throttle plate to reduce or increase air flow necessary to create the stoichiometric 14:1 ratio - at low rpm there is little air flow past the closed throttle plate, so only small quantity of fuel can be injected - more fuel causes flooding and no power - little power can be made at low rpm - a gasser (patooie!) is therefore an rpm\horsepower engine, developing it's power via inertia

In the heat-ignition system, fuel is injected into a cylinder that was just filled with it's full displacement volume of air - no throttle plate - rpm is controlled by adding more or less fuel to each cylinder-full of air - little fuel+lots of air = idle - lots of fuel+lots of air = high rpm - we don' need no steenkin stoichiometric ratios! - the Diesel engine can make big power at low rpm because of the great amount of air in the cylinder at low rpm + the increased BTU content of the fuel - a Diesel engine is therefore a torque engine, developing it's power via thrust on the crank lever as it approaches maximum length at 90deg from the vertical

Because of that ability to make big power below 2000rpm, the stresses in the crank, piston, block and head are much greater than those in the hi-rpm engine, so all the components must be made larger and thicker and stronger than a similar-displacement gasoline engine

Other than that, I dunno.....................

brew1 · **Posted:** Sun Oct 28, 2007 12:50 pm

Had my CRD ECU tuned yesterday with a Rocket Chip Level 1 tune (RC1) at the local VW TDI GTG in Fondulac WI. Only CRD in a parking lot and garage full of TDI's. The RC1 tune among other things, raises the maximum boost pressure to 22 psi. It does not alter the EGR function or delete a CEL associated with EGR disablement through either MAF disconnection or EGR block-off plate.

I stated in my earlier post that Jeff could/would do this(remove foot from my mouth), which he can, however he has not performed the necessary R&D with the CRD ECU program needed to confidently delete the EGR function and the associated CEL and know what other parameters within the ECU program may be adversely affected by this modification. He is also acutely aware of the transmission problems associated with the CRD and would not consider programming a higher level of tune unless those transmission issues have been addressed(upgraded pump & Suncoast TC). I am still under warranty and have not had any issues with the EGR or tranny since we purchased the vehicle this past July with 24,000 miles on it, 29,000 now.

Jeff removed the ECU and reprogrammed the unit on his bench. Interesting to watch. He could have programmed it through the OBD port but explained it would take much longer since the data transfer rate is much slower than doing it on the bench. Interesting to watch him pop the ECU cover, those suckers on on there pretty good. Also interesting to watch the actual programming process and file transfer. He was able to tell that the ECU had been reflashed once since it left the factory. Jeff also showed me where I could splice in a boostvalve, and advised me on a recommended setting. His daily driver is a Jetta TDI sedan, however he commented that he had considered a CRD but was turned off by the poor MPG (compared to the VW TDI) and he puts on plenty of mileage traveling to VW TDI GTG's. Also probably wouldn't look too good pulling up at a VW TDI GTG in a Liberty CRD when your going to be programming their TDI ECU's.

Initial driving impression with the MAF reconnected and the new tune:
CEL reset itself after the engine was turned on/off about 4 times and an hour of driving (MAF reconnected).
Power increase and throttle responsiveness was quickly evident, more so when accelerating onto the freeway from 20 mph to 80 mph, quick & smooth transition. Accelerating from a highway cruising speed of 65 up to 85 was fast & smooth. Very responsive throughout the power band. This is much more noticable than when I run with the MAF unplugged (ORM). I didn't really notice any power gain when doing the ORM, just made the vehicle sound a little louder.

I'll need to see how this affects mileage, overall driving and transmission over the next few weeks and do a new thread with my thoughts on this tune. I really need to run my VIN # through the Chrysler site and find out if my tranny ECU was reflashed(neutered). I have a SEGR unit being shipped to UFO for assembly and installation in this vehicle, hopefully next month. Still need to install the new CAT fuel filter, automatic bleed valve mod, clean MAP, boostvalve, Facet lift pump, fuel cooler, V6 airbox, Transgo shift kit, B&M trans cooler and open up the exhaust. Lot of projects this winter and I really appreciate this site and all the helpful information provided.

BTW, pricing for the ECU programming at the GTG was $295 for the RC1. I believe Jeff said the RC2 would be $365 and he would upgrade to RC2 for the price difference and he would also return the ECU to stock if necessary (for free). RC3 was $400+. I'm not sure how willing he would be to do more Liberty CRD's but you can certainly ask. I was the 3rd CRD he has tuned in the last couple years so he is not really pursuing this market. He is based in Red Lion PA but travels frequently to VW TDI GTG's and also does ECU programming for some competitive VW vehicles. Email info@rocketchip.com cell 717-676-8755. A word of advice, be patient when trying to contact him. He gets a ton of email every day and you may be better calling him on his cell. No, I am not pimping for Jeff, nor do I receive any type of compensation for forwarding business to him. I just wanted to make fellow members aware of another ECU tuning option in lieu of the magical fueling boxes.

I would be interested (after completing a few of my planned mods) to do some dyno testing and see how this programming compares to the InMotion tune on the same dyno. If anyone in the Wisconsin/Illinois area with the InMotion tune is interested, let me know and we can set something up this winter.

Mark

Maximum boost pressure and boostvalve?

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