43 replies to this topic

[speedster]

I think you are missing one key element, you have to do with the M62 efficiency curve

If you want to hit 300+ BHP with low compression (let's say 9:1), you will have to get more boost as you said, so a smaller pulley and you will certainly land in an efficiency zone of the M62 were it is so unefficient you'll never be able to cool the intake air enough.

I am currently spec'ing my next engine after the NA one (autumn 2009 release), it will be a supercharged LE5/LSJ hybrid with a 380BHP target.
CR will be 10.5:1 but not Wiseco
(or specially made ones for boost)


EDIT : oh and another thing specially for you Steve.
Having 8.9 pistons does not mean at all you effectively have 8.9 CR, especially in an hybrid.
LSJ/Saab cylinder head gasket are thinner than 2.2 ones. I am not sure the valves have the same big dish on the 2.0 head too

Hi alanoo,

I agree. Heat saturation is the BIG problem. The 2 pass end-plate helped some but the TVS should now remedy this. I still haven't figure what gasket configuration I'm going to finally run with. The smaller valve areas used in the SAAB turbo head are OK for the SC configuration, a narrower stem on the valve is an option that can be considered though....

Have you figured what piston ring configuration you going to use on a 10:5:1 CR? I've heard of ring failure and oil seepage been an issue on FI running those higher CR's.

Steve

Edited by speedster, 31 March 2008 - 10:49 PM.

[Winstar]

I think you are missing one key element, you have to do with the M62 efficiency curve

If you want to hit 300+ BHP with low compression (let's say 9:1), you will have to get more boost as you said, so a smaller pulley and you will certainly land in an efficiency zone of the M62 were it is so unefficient you'll never be able to cool the intake air enough.

I am currently spec'ing my next engine after the NA one (autumn 2009 release), it will be a supercharged LE5/LSJ hybrid with a 380BHP target.
CR will be 10.5:1 but not Wiseco
(or specially made ones for boost)

That's the nail on the head... The M62 can flow you lots of air IF you keep it in it's efficiency range.. (max 10-12psi) And that is the pressure at the blower outlet!! The LSJ intake manifold is quite restrictive and this will give efficiency problems with higher flows (= HEAT!)
The US guys are at the moment working on a complete new manifold design, but they also ported the standard manifold which significantly improved flow. (Wider laminova slots) Will post a link soon.

(I have a complete LSJ engine waiting, but I'm still figuring out what will be the best solution for my speedster. Personally I think it first should flow (headwork / intake/ exhaust) and rev (valvesprings / balance shaft delete / cams) properly with ~10:1 compression. And then use the M62 to around 10 psi boost and max 15-17000rpm. (The blower that is.)

With well cooled charge temps and some proper tuning... Should be fun enough :-) )

The manifold is quite restricteve due to the Laminova cores, however In the package space available in the vx you will be pushed to fit much else.

Due to the angle that the flow exits a roots super charger, 30 degrees from the horizontal the best solution would be to loop the flow down to the front of the engine into a plenum then come back up through a large plate heat exchanger and into runners, problem is it would end up covering up the oil filter housing.

[slindborg]

I think you are missing one key element, you have to do with the M62 efficiency curve

If you want to hit 300+ BHP with low compression (let's say 9:1), you will have to get more boost as you said, so a smaller pulley and you will certainly land in an efficiency zone of the M62 were it is so unefficient you'll never be able to cool the intake air enough.

I am currently spec'ing my next engine after the NA one (autumn 2009 release), it will be a supercharged LE5/LSJ hybrid with a 380BHP target.
CR will be 10.5:1 but not Wiseco
(or specially made ones for boost)


EDIT : oh and another thing specially for you Steve.
Having 8.9 pistons does not mean at all you effectively have 8.9 CR, especially in an hybrid.
LSJ/Saab cylinder head gasket are thinner than 2.2 ones. I am not sure the valves have the same big dish on the 2.0 head too

Hi alanoo,

I agree. Heat saturation is the BIG problem. The 2 pass end-plate helped some but the TVS should now remedy this. I still haven't figure what gasket configuration I'm going to finally run with. The smaller valve areas used in the SAAB turbo head are OK for the SC configuration, a narrower stem on the valve is an option that can be considered though....

Have you figured what piston ring configuration you going to use on a 10:5:1 CR? I've heard of ring failure and oil seepage been an issue on FI running those higher CR's.

Steve

so youre saying the saab head valves are smaller than std 2.2 N/A valves?

[alanoo]

Hi alanoo,

I agree. Heat saturation is the BIG problem. The 2 pass end-plate helped some but the TVS should now remedy this. I still haven't figure what gasket configuration I'm going to finally run with. The smaller valve areas used in the SAAB turbo head are OK for the SC configuration, a narrower stem on the valve is an option that can be considered though....

Have you figured what piston ring configuration you going to use on a 10:5:1 CR? I've heard of ring failure and oil seepage been an issue on FI running those higher CR's.

Steve

I don't think it will be an issue with forged pistons made for boost.
Maybe some had issues with 10:1 Wiseco's, but as I said, they are not made for boost at all
(and the OE piston has very weak ringlands too)

If you go TVS + 2-pass, heat should not be a problem at all

Edited by alanoo, 01 April 2008 - 08:38 AM.

[Exmantaa]

Some info about the LSJ supercharger manifold:
http://www.cobaltss....ad.php?t=104168

According Eaton specs the M62 blower can be mounted in any position. And when looking to the Exige 240R M62 blower set-up, there is room for ideas. Only then with a proper water/air chargecooler, like the GT3 version has. And with a different air routing, as the flow exits the SC in an angle towards the pulley...

Edited by Exmantaa, 01 April 2008 - 11:42 AM.

[slindborg]

ohhh now that would work well with an RS200 styleeee roof mount IC (well its an aftercooler but we wont get into that lol)

[Winstar]

Some info about the LSJ supercharger manifold:
http://www.cobaltss....ad.php?t=104168

According Eaton specs the M62 blower can be mounted in any position. And when looking to the Exige 240R M62 blower set-up, there is room for ideas. Only then with a proper water/air chargecooler, like the GT3 version has. And with a different air routing, as the flow exits the SC in an angle towards the pulley...

Interesting do you know if it'll fit between the engine and bulkhead in a VX>

would be good if it did, and if it could be combined with the Proalloy Exige S CC system even better

[Exmantaa]

Well, it fits in an exige with the windscoop....

But take a look here: http://www.advancedv...o.uk/avtpwr.htm
Very nice chargecooler design. And in their gallery you can see it mounted on a proper specced Exige.. (among others..;-) )

[Winstar]

Well, it fits in an exige with the windscoop....

But take a look here: http://www.advancedv...o.uk/avtpwr.htm
Very nice chargecooler design. And in their gallery you can see it mounted on a proper specced Exige.. (among others..;-) )

The ProAlloy one's are a much better design, I've looked at that site before and to be honest it makes alot of vague claims with no real data to back it up.

The cylindrical design is good for even diffusion into the cooling channels if you get stright flow entering it, however I have a couple of real issues with their design,

1. looking at this veiw

you can see the most direct flow path through the middle is not open channels, this will cause recirulation and extra pressure loss, there also seems to be high ratio of coolant to air
2. they sayYou will also notice the core is 'segmented'. This is too allow the coolant to flow around the outside circumference of the core, down the middle of the fins and across the fins, so basically coolant can flow in all directions.
Now if you look there inlet and outlet are on the same side if the flows free to go any where, unless it's jetted in a high velcity, it's going to go the shotest path out along one side.

The ProAlloy one, ProAlloy, has 5 pass cores and is designed specifically for use with the vxt/exige layout.

[speedster]

so youre saying the saab head valves are smaller than std 2.2 N/A valves?

Hi slindborg,

I don't have the exact measures to hand but a cylinder head configured specifically for a turbo or supercharger will typically have a valve area ratio giving smaller intakes to larger exhausts. This among other things provides headroom for camming. The Normally Aspirated heads don't have this type of valve ratio and that is probably one of the reasons why the NA heads don't cam well when a SC is bolted on.
If your going to use a turbo head on for a NA application you will need to improve the intake valve performance, plus match the intake ports and the exhuast valve performance with your modifications..... then look for cams that will work best in your custom head!

Steve

Edited by speedster, 02 April 2008 - 12:56 PM.

[slindborg]

so youre saying the saab head valves are smaller than std 2.2 N/A valves?

Hi slindborg,

I don't have the exact measures to hand but a cylinder head configured specifically for a turbo or supercharger will typically have a valve area ratio giving smaller intakes to larger exhausts. This among other things provides headroom for camming. The Normally Aspirated heads don't have this type of valve ratio and that is probably one of the reasons why the NA heads don't cam well when a SC is bolted on.
If your going to use a turbo head on for a NA application you will need to improve the intake valve performance, plus match the intake ports and the exhuast valve performance with your modifications..... then look for cams that will work best in your custom head!

Steve

Good job I got the SAAB head cheap then lol. I'm hoping the modified N/A head I'm going to measure on Friday has stock valves so that I can get a good comparrison to the SAAB one.
Or I could skip making it work for N/A use and save it for some FI later on next year lol

lots of fun

cheers
Stuart

[Exmantaa]

In the Ecotec build books I can't find any mentioning of different valve diameters.

Ecotec 16 valve head:
35,1mm intake & 28mm exhaust diameter
For the LSJ (=Saab head) they mention Sodium filled exhaust valves.


@ Winstar:

I'll not debate if these coolers are the best you can get, but I do like some features which I did not see on other chargecoolers. Among others the reversed flow cooling path, which is a must for an efficient heat exchanger design. (And they say there are internal coolant flow guides to prevent the shortcut route.)
But I have to take a deeper look into the pro-alloy design...

(And sadly I do not have an Exige 240R (or VXT), so will have to design my own system around the LSJ engine. )

[vocky]

I thought the valve sizes were the same for the lsj + z22se

[speedster]

so youre saying the saab head valves are smaller than std 2.2 N/A valves?

Hi slindborg,

I don't have the exact measures to hand but a cylinder head configured specifically for a turbo or supercharger will typically have a valve area ratio giving smaller intakes to larger exhausts. This among other things provides headroom for camming. The Normally Aspirated heads don't have this type of valve ratio and that is probably one of the reasons why the NA heads don't cam well when a SC is bolted on.
If your going to use a turbo head on for a NA application you will need to improve the intake valve performance, plus match the intake ports and the exhuast valve performance with your modifications..... then look for cams that will work best in your custom head!

Steve

Opp! My head is on backways!
That should read..... a cylinder head configured specifically for a turbo or supercharger will typically have a valve area ratio giving smaller intakes and larger exhausts when compared to an NA configuration.

Meaning, exhaust valve area on a NA configuration is typically between 65% to 75% of the area covered by a intake valve.
On a FI engine the exhaust valve area can go up to 90% of the intake area.....

Exmantaa, those sizes are the same as the L61 head ok....

[slindborg]

so the valves will be common sized across the heads, but the FI exhaust valves will be sodium filled.

[speedster]

so the valves will be common sized across the heads, but the FI exhaust valves will be sodium filled.

on the LSJ head intakes are undercut slightly so there's a little more intake breathing space.

[slindborg]

so the valves will be common sized across the heads, but the FI exhaust valves will be sodium filled.

on the LSJ head intakes are undercut slightly so there's a little more intake breathing space.

I'll have to get this SAAB head in bits to see what the score is with that then

[Exmantaa]

I used to have a working link where an L61 head was cut to pieces, so you could see the different wall thicknesses.

This one is also good: http://www.ecotecfor...read.php?t=5344
Differences & possibilities LSJ (Saab) vs. L61 (2,2 eco) head!

[RobNA]

I wish I knew more about engines

[alanoo]

I thought the valve sizes were the same for the lsj + z22se

They are


slindborg, sell me this head