Boost levels?

[appletonn]

For those of us struggling along in the vastly inferior (Hi Oli! ) turbocharged variants of the 944 breed, I was wondering what boost levels we are all running. Curious as I was advised by Lindsey Racing (I know, I know [8|]) that 16psi should be the figure to run with with the mods on my car, but I know that some are much higher.

I'll start:

16psi with a K26/8 turbo, 3 bar Bosch Fuel regulator, standard injectors, LR chipsets, MBC and DPW - separate VDO boost gauge used to indicate peak boost.

Edited to add - forgot the Bailey DV30 Recirc valve

 

[rcsalmons]

Nick

I have exactly the same set up as you with either MAXHP or JM chipset and I run 18psi. Changed the head gasket last year - preventative.

With that set up it made 294 or 274hp on different DD dyno's.

Rich

 

[homesea]

0.75 Bar (so just under 11psi) with K26/6 turbo, 3 bar Bosch fuel reg, standard injectors, MBC, Tial DPW, Baily by-pass valve.

Got some MAX thingy chips not fitted yet, need a air/fuel gauge so I can set it up.

Anyone know what kind of boost I should be aiming for?

 

[MarkK]

1.5 bar on my 89...,1 bar and a bit on my 90.Both tuned by Promax.[]

 

[TTM]

ORIGINAL: appletonn
16psi with a K26/8 turbo, 3 bar Bosch Fuel regulator, standard injectors, LR chipsets, MBC and DPW - separate VDO boost gauge used to indicate peak boost.

I had the same set up on my 2.5 except I was using MAXhp chips (which now should be the ones sold by LR anyway) with the SciVision MAF.
There was no sign of knock when running 16 psi but once running 18 psi knock would appear periodically, mostly depending on where I filled the tank. While I drove the car last winter in sub zero temperatures it showed no knock running 19 psi, but I did not feel like pushing my luck any further and did not raise the boost higher.
All other things considered equal, I'm pretty sure a more efficient intercooler would allow running more boost without risking knocking down the engine (pun intended).

ORIGINAL: MarkK
1.5 bar on my 89

I take it you do not have the stock intercooler anymore?
My mate Sly with a LR75 on his Silver Rose found out that this turbo works best in this pressure range, but the engine was knocking like mad [&:]

 

[rcsalmons]

ORIGINAL: TTM

ORIGINAL: appletonn
16psi with a K26/8 turbo, 3 bar Bosch Fuel regulator, standard injectors, LR chipsets, MBC and DPW - separate VDO boost gauge used to indicate peak boost.

I had the same set up on my 2.5 except I was using MAXhp chips (which now should be the ones sold by LR anyway) with the SciVision MAF.
There was no sign of knock when running 16 psi but once running 18 psi knock would appear periodically, mostly depending on where I filled the tank. While I drove the car last winter in sub zero temperatures it showed no knock running 19 psi, but I did not feel like pushing my luck any further and did not raise the boost higher.
All other things considered equal, I'm pretty sure a more efficient intercooler would allow running more boost without risking knocking down the engine (pun intended).

This might be a stupid question but knock..... do you feel it, hear it or what other symptons??

Rich

 

[TTM]

I use a little box with a bulb that connects to the KLR and reads the input from the knock sensor. Though at these relatively "low" pressures it's not audible knock, it can still be destructive.

 

[sawood12]

I'm running the Promax L2 kit (3 bar FPR, MBC, DPW) with 1 bar boost chipset running at 15psi max on a K26/6 on stock injectors. Running AFR's and Scivision it is important to set your boost level to match your chipset.

 

[barks944]

ORIGINAL: TTM

ORIGINAL: appletonn
16psi with a K26/8 turbo, 3 bar Bosch Fuel regulator, standard injectors, LR chipsets, MBC and DPW - separate VDO boost gauge used to indicate peak boost.

I had the same set up on my 2.5 except I was using MAXhp chips (which now should be the ones sold by LR anyway) with the SciVision MAF.
There was no sign of knock when running 16 psi but once running 18 psi knock would appear periodically, mostly depending on where I filled the tank. While I drove the car last winter in sub zero temperatures it showed no knock running 19 psi, but I did not feel like pushing my luck any further and did not raise the boost higher.
All other things considered equal, I'm pretty sure a more efficient intercooler would allow running more boost without risking knocking down the engine (pun intended).

ORIGINAL: MarkK
1.5 bar on my 89

I take it you do not have the stock intercooler anymore?
My mate Sly with a LR75 on his Silver Rose found out that it works best in those pressure range, but the engine was knocking like mad [&:]

Lowering the charge air temp will reduce the chances of pre-ignition, so I think you should be able to increase the boost. I'm not sure how much boost you would gain for any given drop in air temp though. Maybe you could hook the boost controller up to the knock sensing system?

 

[Suffolk944]

Am running 1.2 bar (no idea what that is in Psi) along with the Promax chips DP wastegate and electronic boost controller.

 

[sawood12]

Jon, how do you find your Apexi? some people say their EBC's (not just Apexi's) struggle to hold consistent boost and can have occasional spikes. I've got one boxed up but am a bit apprehensive about fitting as my MBC is just so reliable.

 

[944 man]

Id be extremely interested to see at what engine speeds people were developing full boost; and with which turbochargers.

 

[sawood12]

On a K26/6 mines hitting max boost of 15psi at 3krpm, but that boost level is not held for any length of time and bleeds down linearly to about 10psi at 6500 rpm.

 

[DavidL]

ORIGINAL: rcsalmons

Nick

I have exactly the same set up as you with either MAXHP or JM chipset and I run 18psi. Changed the head gasket last year - preventative.

With that set up it made 294 or 274hp on different DD dyno's.

Rich

My first impression is that this doesn't seem all that much for that sort of spec?
That's where I'm going with perhaps an EBC and maybe different injectors but I would expect more - or am I being too optimistic?

 

[Suffolk944]

Scott, have had my EBC for a year now and have been very pleased with it not had a single glitch. Certainly feel it holds boost better further up the rev range than the MBC I had fitted to my previous car (though that was good too as you say).

 

[Diver944]

ORIGINAL: appletonn

16psi should be the figure to run with with the mods on my car, but I know that some are much higher.

I'm set to 18psi (1.2bar) with Garret ballbearing turbo, 3 bar FPR, 72lb injectors, Bosh 044 fuel pump, Vitesse MAF and Piggyback, Greddy EBC and Tial 46mm wastegate

I imagine Lindsey recommended you stay at 16psi because you still have standard injectors and run the risk of going lean at high revs if you go any higher

I hit 15psi (1bar) at 2900rpm and 18psi at 3100rpm

 

[Frenchy]

I think i may need to turn mine down until i source some bigger injectors [:-] modified re sprung wastgate,promax chips, 3bar fpr,cometic headgasket,bailey DV,adjustable boost (bleed valve) standard injectors boosts to 18 psi on a vdo gauge and tails off sharpish at higher RPM.
What is the best place to get bigger injectors and how to i get the beasty to hold onto boost longer []
Tip for the day !
Did you know by compressing the original fpr between to suitable sockets compresses the internal spring and up's it's pressure rating, i saw Wayne Schofield of Chip Wizards carry out this trick a few years ago.

 

[sawood12]

There are plenty of people running upto 1.2 bar Promax kits on stock injectors ad 3 bar FPR's. It probably isn't advisable but I guess our saving grace is that our stock turbo's can't hold flow enough air to hold boost pressure to the red line anyway so as the RPM rises the boost pressure is dropping therefore less fuel needed. Though it is always better to be safe than sorry and upgrade injectors. THe good thing about the Promax chips is that if you get Delphi 68 lb (or 55 lb I think) they are mapped for those injectors as well and the maps can be selected via the FQS, so no need to change chips. I'm sure Promax could sort you out with some injectors.

I wouldn't simply turn the boost down though or you'll be running rich as the chips are mapped to assume you are running a certain boost pressure and fuel accordingly.

 

[Frenchy]

Cheers Scott, i presume you mean the chip settings on the dip switches will need changed for 55lb injectors ? i will speak to promax about injectors.
I may see myself chucking some money at the car next year for some Big HP []

 

[MarkK]

Thom-The intercooler is a Lindsey item[]