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Supercharger FAQ - MAF vs. MAFless discussion


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Bill Schimmel does 4" MAF housings, and indeed I have a spare one. I'll give it to Vince to experiment with on some customers cars. It's OBD2 only though. OBD1 MAFs need custom housings made up and

vince works for stealth I have never met or spoke to him but the guy knows his stuff.

Give him a call on 01926 812259 is very helpful

OK chaps.

Went with a MAF setup on my OBD2.

Few hiccups, like my MAF extension loom being suspect causing a MAF fault code error to ground.

And found out that the pulley on the charger is 6psi :@ . Brought it s/hand and got a 2nd spare pulley in a box. Was told at the time of purchase that the pulley already on the charger was an 8psi, and the one in the box was 6psi. :@ :@ . Hopefully the one in the box is the 8psi. Does anyone know the diameter of the 8psi pulley?

Vince mapped it anyway with the redtops, 6psi puley, MAF, and water injection and acheived 270bhp, which at this time i'm more than happy with, seeing as the advertised power on a stage 1 (6psi) is 250 and on stage 2 (8psi) it's 280 ( i know most of you reading this already know the published figures :$ )

To be honest i might stay with this setup for a while, because the cost of remapping for an extra 10 horses is just not worth it at this time.

Anywho..., lets see how she runs at thr ring this weekend :-p

On another note, does anyone with a charger setup with recirc valve experience a surge while driving just after lifting off the accelerator? Vince assured me it's a common symptom

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Guest jayvr6

ive just got my self a lovely vr6, and i really really want to treat it with a supercharger, dose any one know where i could buy one and get it fitted?? please help!!

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after a very accurate measurement down at the phirm i can confirm that i'm running an 8psi pulley after all. So my lost boost is down to something else, maybe a boost leak at high revs or maybe pitted fins in my 3rd hand charger. The investigation continues. But yeah not bad figures from 6psi boost.

but back on topic, vince's MAF map seems to work a treat so far. it's just done a trip to the ring and i'm very happy with it for now. I've experienced no cold starting issues at all, and after just shy of 1600 miles in a week it's behaving very well indeed.

And for reference:

3.25" Pulley

Boost up to 6-7 psi

3.12" Pulley

Boost up to 8-9 psi

2.87" Pulley

Boost up to 10-11 psi

2.75" Pulley

Boost up to 12 psi

2.62" Pulley

Boost up to 13 psi

2.5" Pulley

Boost up to 15 psi

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nice guide mate boost gauges are pretty cheap and will tell you if its losing boost anywhere as itl stop climbing

how is your car when goin from higher throttle to lower throttle mines been getting gradually more jerky over the last month or so is urs stock smoot?

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Interesting on the pully dimms! When I first started on my map - boost was low at about 7psi. that could also explain my overall lower than expected power. I will have to buy a piece of string and measure it ! Mmmmmmm.

I have had a great MAF map also and works a treat - equal to OEM standard! Got about 600 miles on since and not experiencing any of those jerky isssues some mention at all. I was given a warning from Vince; that with the MAF you need to ensure you keep the MAF clean as it will get a build up of oil on it every so often and that will/can cause it to run like a bag of spanners as it gradually gets worse. (Comes from the breather pipes).

May be worth a quick clean before you go any further!

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after a very accurate measurement down at the phirm i can confirm that i'm running an 8psi pulley after all. So my lost boost is down to something else' date=' maybe a boost leak at high revs or maybe pitted fins in my 3rd hand charger. The investigation continues. But yeah not bad figures from 6psi boost.

but back on topic, vince's MAF map seems to work a treat so far. it's just done a trip to the ring and i'm very happy with it for now. I've experienced no cold starting issues at all, and after just shy of 1600 miles in a week it's behaving very well indeed.

And for reference:

3.25" Pulley

Boost up to 6-7 psi

3.12" Pulley

Boost up to 8-9 psi

2.87" Pulley

Boost up to 10-11 psi

2.75" Pulley

Boost up to 12 psi

2.62" Pulley

Boost up to 13 psi

2.5" Pulley

Boost up to 15 psi

[/quote']

Those figures are for the larger v1/v2 chargers. The v9 won't make those levels of boost with the same size pullies.

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To be honest i might stay with this setup for a while' date=' because the cost of remapping for an extra 10 horses is just not worth it at this time.[/quote']

Standalone ;-) LOL, only kidding mate. 270hp from 6psi is top dollar my man, you should be chuffed with that. My personal favourite of my 3 S/C setups was the 2.9 OBD2 8psi Vince MAF map and that made the numbers on the nail, 290hp with 260 torque....so with the same pulley, you'll hit that no worries, maybe a pinch more.

10 psi upwards gets awkward with the stock management and the MAF will definitely need to go IMO. I ran 12psi and it was barely any quicker than 8psi because the stock management just couldn't cope with it, and the heatsoak (no intercooling at the time) didn't help matters.....which is where the whole 4" MAF (or standalone) business comes in + inter or charge cooling. 8psi is the industry standard limit without cooling.....there after you need it. The temperature of the charger air will be about 70 degrees with a 12psi pulley and that really does need cooling down.

On another note' date=' does anyone with a charger setup with recirc valve experience a surge while driving just after lifting off the accelerator? Vince assured me it's a common symptom

[/quote']

Yes chap, been there, got the T shirt. You need to play around with the spring rates in the valve. Get yourself a spring tuning kit from Forgemotorsport. I recommend the blue spring.

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To be honest i might stay with this setup for a while' date=' because the cost of remapping for an extra 10 horses is just not worth it at this time.[/quote']

Standalone ;-) LOL, only kidding mate. 270hp from 6psi is top dollar my man, you should be chuffed with that. My personal favourite of my 3 S/C setups was the 2.9 OBD2 8psi Vince MAF map and that made the numbers on the nail, 290hp with 260 torque....so with the same pulley, you'll hit that no worries, maybe a pinch more.

10 psi upwards gets awkward with the stock management and the MAF will definitely need to go IMO. I ran 12psi and it was barely any quicker than 8psi because the stock management just couldn't cope with it, and the heatsoak (no intercooling at the time) didn't help matters.....which is where the whole 4" MAF (or standalone) business comes in + inter or charge cooling. 8psi is the industry standard limit without cooling.....there after you need it. The temperature of the charger air will be about 70 degrees with a 12psi pulley and that really does need cooling down.

On another note' date=' does anyone with a charger setup with recirc valve experience a surge while driving just after lifting off the accelerator? Vince assured me it's a common symptom

[/quote']

Yes chap, been there, got the T shirt. You need to play around with the spring rates in the valve. Get yourself a spring tuning kit from Forgemotorsport. I recommend the blue spring.

u git u never told me that lol

iv got the lumpyness when comin off the throttle il play around with the springs tomorow just gotta remember where i put em hehe

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Yes chap' date=' been there, got the T shirt. You need to play around with the spring rates in the valve. Get yourself a spring tuning kit from Forgemotorsport. I recommend the blue spring.

[/quote']

I've got a forge valve with a blue spring, still get a weird surge when cruising at about 110 (on a private road ;) )

But apart fromt that it's running pretty good so far

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Guest simplyvr6

no i am not yet but i live in bracknell and was thinking about getting one i saw one fitted at spring festival the car was running 12.8 quarters on a standard engine - in comparison made the vortech seem a waste of time this unit looked neater - faster - no belt problems - does sound like a toy.

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Guest simplyvr6

I think it was done in the south sounded amazing tbh i think it is one of the fastest ever vr6's supercharged cars on a standard engine in 2wd - it sounded awesome - the fitting was excellent - the guys name is drew he is over the moon with it - super rapid vehicle terminal speed 120mph

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Cadguy, are you running a bored out throttle mate? That can also cause the surging you describe. Basically it's the map coming off open loop and going back to lambda. I take it the surging is OK at full throtte? It's just coming down again and part throttle?

Did I ever recommend a standalone to you? PMSL....you're going to hit me if I say that again :-)

Hmm, I wondered how long it would be before the Rotrex would be mentioned in comparison to the "noisy rattley toy" :-)

It's quick is because it boosts lower than the Vortech and has less parasitic load....and it's making like 10psi minimum for stage 1.

Stage 2 is about 15psi IIRC....

I reckon it's a StormDevelopments car in question.

They use a planetry gear system, which is more efficient and quieter than Vortech's method.

Good chargers.

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Cadguy' date=' are you running a bored out throttle mate? That can also cause the surging you describe. Basically it's the map coming off open loop and going back to lambda. I take it the surging is OK at full throtte? It's just coming down again and part throttle?

Did I ever recommend a standalone to you? PMSL....you're going to hit me if I say that again :-)

[/quote']

No i have a std OBD2 TB Kev.Yeah that's right, coming off throttle and part throttle, but part throttle is only bad when at say 110mph, don't seem noticable at lower speeds.

Can't afford standalone mate, so std management will have to do for now :-|

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Yeah I had that with OBD2 aswell mate, and with the standard throttle too come to think of it.

Vince said it was the ECU coming off open loop and into closed lopp whilst there still being a lot of air going in from the charger.

I suppose that's the advantage of a turbo, as you as you let off the gas, the boost goes into -Hg straight away, whereas as a charger is still boosting as the engine slows down which gives a bit of part throttle snatching.....

One thing we've learned during the supercharger journey is no two engines are the same!! Some exhibit these problems and others don't, which is why it's proving difficult to nail the little quirks once and for all.

Stick with it, you'll get there in the end.

Perhaps it needs a touch more fuel as you're coming down from high rpms to aid the transition into closed loop?

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