83 replies to this topic

[mandarinvx]

How would the boost and torque graphs differ between an M62/Harrop and a Rotrex? I was led to believe the power delivery/driveablity characteristics were not as good on a Rotrex charger.

Ok, so you can't really compare, but here is a graph for an S2000 (with charge cooling) - still seems nice and linear

[Retset]

The Rotrex graphs I have seen are linear. An intercooler is sufficient I think - all it would mean is that you could not get your 250bhp in a traffic jam There were postings on here once from an Italian gentleman with a Rotrex'd Speedster. None in the UK though I think.

[Muncher]

The torque doesn't come in until right at the top of the rev range then?



So at about 2,200 rpm the Rotrex produces less than 50% of it's available torque.

Yet the M62 will be producing nigh on maximum torque at that point, the area under the torque curve varies massively. Surely given those characteristics the M62/Harrop powered car would be long gone.

Also with the z22se which is less inclined to rev very highly that makes the it all the more worse as you won't be able to easily exploit that torque with it right at the top end of the rev range?

[mandarinvx]

I'm not sure - it may just be that the charger replicates the characteristics of the engine (and the graph above is a Honda )

[Muncher]

I'm not sure - it may just be that the charger replicates the characteristics of the engine (and the graph above is a Honda )

I don't think so as the standard torque curve is relatively flat.

[Winstar]

However they would only mak sense if you where either going make a cheap sc conversion that made 250 - 260 bhp without charge cooling or make a 400bhp monster using a C30-94 which has one of the best compressor designs available.

Can I ask why you would say that?

250-260 bhp would be more than enough for me, but I would think that with no chargecooler/intercooler you would only have that bhp for a short while, so no good for track driving, especially with high temperatures... Am I wrong?

you only loose power with an IC or CC when it get heat soaked and the ecu backs off. with the ecu mapped with no cooling then there will always be the same amount of power available.

CF chargers power delivery is dependent on how fast you can spin them up but they do tend to only get up to boost in the upper part of the rev range as you can't spin them up fast enough at low revs.

[siztenboots]

pah, come to the track when you ave 400+ ft/lbs and then you are talking, I will be waiting

[slindborg]

pah, come to the track when you ave 400+ ft/lbs and then you are talking, I will be waiting

with an overheated clutch and no gears

[NickB787]

Be interesting to see how much heat the Rotax does generate as any compression will generate heat, the centrifugal compressor isn't very effective what we need is a light weight axial flow one. cost a bit though


latham axial flow



"One unusual design is Latham's "Axial Flow" supercharger that resembles a fan compressor from a jet engine. A cylindrical rotor with dozens of little blades spins inside a bladed housing to compress the incoming air in stages. Like a centrifugal supercharger, it runs at high speed (470 percent overdrive) and is not a positive displacement pump but more of a high volume fan with an operating speed around 20,000 rpm! One of it's claimed advantages was a much lower outlet air temperature than a Roots type blower. The Latham supercharger was produced briefly from about 1955 to 1965, but never gained widespread acceptance."

Edited by NickB777, 08 June 2009 - 08:39 AM.

[siztenboots]

pah, come to the track when you ave 400+ ft/lbs and then you are talking, I will be waiting

with an overheated clutch and no gears

thats no fault of the car , just a stupid driver

[Winstar]

Be interesting to see how much heat the Rotax does generate as any compression will generate heat, the centrifugal compressor isn't very effective what we need is a light weight axial flow one. cost a bit though

A cetrifugal compressor generated alot less heat as it gerates pressure by recovering static presure from dynamic pressure ie speed the gas up to squash the molecules together then slow it down again so there are lot of molecules trapped in the space. Rather than physicaly compressing a specific volume of gas like a roots SC or a piston (a screw or TVS rotor is a combination of both effect).

Axial compressors are good for high flow low presure increase which is why they arn't used for turbos but are for jet engines.

It's quite easy to calculate the given outlet temp for an inlet temp from a map.

[fiveoclock]

it really depends what you want

if you like na power then I would advise the following parts;

eagle steel rods
z22yh 11:1 cr pistons
balancer delete
lightened flywheel
under drive crank pulley
CompCams stage 3 na cams
ported head
webcon throttle bodies - remapped by northampton motorsport
piper 4-1 exhaust manifold
piper 2.5" system inc sports cat

if you want sc power then I would advise these parts;

GM sc and inlet manifold
Courtenay DIY sc kit
pro-alloy chargecooler
Courtenay remap
piper 4-1 exhaust manifold
piper 2.5" system inc sports cat

To make my decision even harder I have, today, been offered by TMS an engine that was built for the Britcar 24 hour race. Webcon throttle bodies, schrick cams, double springs, re-worked head, lightened flywheel, race clutch, balancer delete. Now I really dont know what to do.

[vocky]

To make my decision even harder I have, today, been offered by TMS an engine that was built for the Britcar 24 hour race. Webcon throttle bodies, schrick cams, double springs, re-worked head, lightened flywheel, race clutch, balancer delete. Now I really dont know what to do.

depends on the price, but I think that engine was 220 bhp

don't forget your old engine is worth between £500 and £850 depending on mileage

[Scotsdave]

it really depends what you want

if you like na power then I would advise the following parts;

eagle steel rods
z22yh 11:1 cr pistons
balancer delete
lightened flywheel
under drive crank pulley
CompCams stage 3 na cams
ported head
webcon throttle bodies - remapped by northampton motorsport
piper 4-1 exhaust manifold
piper 2.5" system inc sports cat

if you want sc power then I would advise these parts;

GM sc and inlet manifold
Courtenay DIY sc kit
pro-alloy chargecooler
Courtenay remap
piper 4-1 exhaust manifold
piper 2.5" system inc sports cat

To make my decision even harder I have, today, been offered by TMS an engine that was built for the Britcar 24 hour race. Webcon throttle bodies, schrick cams, double springs, re-worked head, lightened flywheel, race clutch, balancer delete. Now I really dont know what to do.

Having had a throttle bodied car before (not in a vx220 but still a vauxhall) I would wait on the supercharger.

Nothing has been done to the bottom end in that spec and I would be wanting a strong bottom end as you'll be revving the car alot with throttle bodies and the 2.2 doesn't really like to rev in standard trim (standard 6200 rpm limit) long stroke

I reckon you'll be happy for a couple of months with the tb's then you would be looking for more which isn't going to be cheap and will mean a bottom end rebuilt i.e new high comp pistons etc. With the super charger your 100bhp better off right away and shed load more torque.

250bhp in a vx220 is more than enough to keep anyone happy you'll get used to it eventually but I doubt it would be boring.

With the tb's it's not a case of fitting them, you'll have the additional cost of mapping. Sure the ecu you get will have a base map for the engine spec but it will be a safe map with conservative ignition timing and a rich mixture to make it work with engines in different conditions of health.

Be patient and wait on courtenay as has been said before In the 10 yrs i've been around vauxhall forums I have never read a bad word said about them. You can't say that about the other vauxhall tuners out there

[fiveoclock]

To make my decision even harder I have, today, been offered by TMS an engine that was built for the Britcar 24 hour race. Webcon throttle bodies, schrick cams, double springs, re-worked head, lightened flywheel, race clutch, balancer delete. Now I really dont know what to do.

depends on the price, but I think that engine was 220 bhp

don't forget your old engine is worth between £500 and £850 depending on mileage

Its about the same price as a stage 2 sc install, my engine has only done 15000 miles and I have considered this.

Edited by fiveoclockhero, 08 June 2009 - 12:00 PM.

[fiveoclock]

it really depends what you want

if you like na power then I would advise the following parts;

eagle steel rods
z22yh 11:1 cr pistons
balancer delete
lightened flywheel
under drive crank pulley
CompCams stage 3 na cams
ported head
webcon throttle bodies - remapped by northampton motorsport
piper 4-1 exhaust manifold
piper 2.5" system inc sports cat

if you want sc power then I would advise these parts;

GM sc and inlet manifold
Courtenay DIY sc kit
pro-alloy chargecooler
Courtenay remap
piper 4-1 exhaust manifold
piper 2.5" system inc sports cat

To make my decision even harder I have, today, been offered by TMS an engine that was built for the Britcar 24 hour race. Webcon throttle bodies, schrick cams, double springs, re-worked head, lightened flywheel, race clutch, balancer delete. Now I really dont know what to do.

Having had a throttle bodied car before (not in a vx220 but still a vauxhall) I would wait on the supercharger.

Nothing has been done to the bottom end in that spec and I would be wanting a strong bottom end as you'll be revving the car alot with throttle bodies and the 2.2 doesn't really like to rev in standard trim (standard 6200 rpm limit) long stroke

I reckon you'll be happy for a couple of months with the tb's then you would be looking for more which isn't going to be cheap and will mean a bottom end rebuilt i.e new high comp pistons etc. With the super charger your 100bhp better off right away and shed load more torque.

250bhp in a vx220 is more than enough to keep anyone happy you'll get used to it eventually but I doubt it would be boring.

With the tb's it's not a case of fitting them, you'll have the additional cost of mapping. Sure the ecu you get will have a base map for the engine spec but it will be a safe map with conservative ignition timing and a rich mixture to make it work with engines in different conditions of health.

Be patient and wait on courtenay as has been said before In the 10 yrs i've been around vauxhall forums I have never read a bad word said about them. You can't say that about the other vauxhall tuners out there

Thanks for the advice, you are right, I just have to convince myself to hang on.

[Muncher]

Thanks for the advice, you are right, I just have to convince myself to hang on.

Also bear in mind the torque difference of a throttlebodied car, only produces ~150 lb/ft



Stage 2 supercharger conversion on the other hand produces over 225lb/ft




That's a considerable difference. The idea that a standard TB converted car is 2 seconds a lap quicker than a Stage 2 SC car is just laughable.

[NickB787]

Or just do this

[The Batman]

[Sticky]

That's a considerable difference. The idea that a standard TB converted car is 2 seconds a lap quicker than a Stage 2 SC car is just laughable.

But you're not taking into account brakes, tyres and most importantly the driver. All those things can easily add up timewise.