Author Topic: how does an LDA work if you have a supercharger? (Read 5529 times)

oldskool rich · « **on:** May 21, 2008, 06:12:59 pm »

if a supercharger is more or less the same boost all the way through the revs surly the LDA is useless cus there will be no extra boost to push the pin down

anyone?

smoken u · « **Reply #1 on:** May 21, 2008, 06:20:49 pm »

superchargers still have a pressure difference in the revs, as it revs higher, the CFM of air that it pushes increases.

oldskool rich · « **Reply #2 on:** May 22, 2008, 07:08:40 pm »

i hav a massive supercharger off a V8

should i run just the supercharger or a turbo too?

:?

RabbitJockey · « **Reply #3 on:** May 22, 2008, 07:12:08 pm »

id get the supercharger figured out first then add the turbo to help complicate what u already figured out haha. but yeah the lda will work the same since superchargers still have to wind up, they're not instant the way retards on myspace forums say. omgzor supercharger vs. turbo charger. turbos always win. turbo lag is a myth created by people that drive turbo chevy spirits

fastvicar · « **Reply #4 on:** May 23, 2008, 05:30:32 am »

Kinda depends on your supercharger. A centrifugal sc will have to "wind up" since they are essentially a turbo's compressor that is driven by a belt. They need higher rpm to build boost. However, a positive-displacement unit like what you'd find on a Mini S or a GT500 Mustang will give you instant-boost whenever you want it. Unfortunately, they also produce boost when you don't need it.

I agree that in an efficiency contest a turbo will win hands-down. However, turbo lag is a very real problem in older cars (IDIs included). Only in the last 10 years or so have turbos become nearly seamless in their power delivery.

KTZed · « **Reply #5 on:** May 23, 2008, 08:37:37 am »

Quote from: "Trev0rbr"

turbo lag is a myth created by people that drive turbo chevy spirits

And 1.6TD's with T3's :roll:

oldskool rich · « **Reply #6 on:** May 23, 2008, 07:40:37 pm »

i hav a positive-displacement supercharger eaton m112

about as big as you can get, my mate tells me that its not about psi and its all about air flow, aparentlty this will flow much better than my T3

so i think it will make the old truck alot faster, and loose all that annoying lag, anyone know what sort of power i might expect?

tbh im fed up of turbos, it seems that they only last me a few months with the boost cranked up :cry:

xud9te · « **Reply #7 on:** May 24, 2008, 05:03:31 am »

Its TOO BIG for a 1.6 td! Maybe look at the M45. Eaton SC numbers indicate the volume per rev in CI.

The 112 outputs 1.8 litres per rev. Even if you wanted 30 psi at 6000 it would still only be wanting to turn at 0.88 of the engine speed (5280rpm). This will drop the SC right out of its efficiency range. Rootes SC's only really starts to make boost at about 4500rpm; before that the air leaks back past the rotor gaps due to lack of inertia, so you may get hardly any boost at all until say 5100rpm on the tacho. To run this SC in the airflow range it was designed for you would have around 50psi on the 1.6.

An M45 would be spinning at 2.17 times (13,000 rpm) max which is about cock on, and would start to make good boost at idle almost with an efficiency peak right on your max torque at around 3250.

KTZed · « **Reply #8 on:** May 24, 2008, 09:41:30 am »

Quote

Its TOO BIG for a 1.6 td! Maybe look at the M45. Eaton SC numbers indicate the volume per rev in CI.

The 112 outputs 1.8 litres per rev. Even if you wanted 30 psi at 6000 it would still only be wanting to turn at 0.88 of the engine speed (5280rpm). This will drop the SC right out of its efficiency range. Rootes SC's only really starts to make boost at about 4500rpm; before that the air leaks back past the rotor gaps due to lack of inertia, so you may get hardly any boost at all until say 5100rpm on the tacho. To run this SC in the airflow range it was designed for you would have around 50psi on the 1.6.

An M45 would be spinning at 2.17 times (13,000 rpm) max which is about cock on, and would start to make good boost at idle almost with an efficiency peak right on your max torque at around 3250.

I agree...thats a huge blower. If you want something that will live at 30psi and be driveable get a new Garrett GT30 ball bearing turbo or something....or try running a super/turbo combination. Look at the HKS Twincharger kits they made for 1st gen MR2's.

oldskool rich · « **Reply #9 on:** May 24, 2008, 01:36:37 pm »

ok so to summerise it wouldnt make me go as fast as an m45 would?

a mate of mine wants to swap an m45 for the m112 should i do this?

is it gona be faster than a T3?

would it be better to run the m112 with my t3?

snakemaster · « **Reply #10 on:** May 24, 2008, 02:33:17 pm »

hey Rich vnt 20 turbo with a manual auc its worth dooing your homework
on to see if it would work for you ,and a lot less stress than fitting a SC

oldskool rich · « **Reply #11 on:** May 24, 2008, 05:12:10 pm »

i know vnt20s are amazing, but where the hell do i get one from?

i dont hav much cash :cry:

it would help to know what cars they are on as standard

snakemaster · « **Reply #12 on:** May 25, 2008, 02:02:31 am »

i won a split new one on ebay for £51 and the guy did not sent it , he said he droped it and smashed the inlet part , then 5 weeks later back on ebay as new :evil: but this one was of a lt 35 , and a few merks have vnt 20 or vnt 22 there are some times listed as GT 20 or GT 22 , 2.5 a6 some of them have a vnt 20 the newer ones i think , for more power lpg injection and a kit can be made up cheap could ad on about 30 to 40 foot pounds torque , 15 kg bottle of gas in the back of the pick up , and when parked up use for your camping stove ( hot knifes

)

carrizog60 · « **Reply #13 on:** May 25, 2008, 02:15:57 am »

would the vnt bolt on on the 1.6 manifold straight?
what is involved on doind thjis conversion?

xud9te · « **Reply #14 on:** May 25, 2008, 07:37:24 am »

I got my GT2052 on ebay.de for less than 100 quid. Was 135 when it arrived in UK after all taxes I think.

M45 would be faster than M112 on the engine at sensible boost. M112 will not really work that well. On the other hand, the M112 is worth a hell of a lot more than the 45. The 45's are taken off the MINI when upgrading to Cooper works spec and they turn up on ebay all the time for less than 80 quid.

adding the SC on a diesel has got to be just as easy as the VNT route, if you can get hold of an AC bottom pulley, belt and NA manifold.

The best option is a compound with the T3 and m45. Blow the turbo into the SC and then IC. Use an external wastegate on the inlet pipe after IC to control boost over a certain point (say 30psi) and also leave the standard actuator on the turbo. No lag and big boost. You lose some of the pressurized air to atmos, but if you gear the SC correctly it should not be alot. The maths is pretty simple to get a good ballpark figure, then you can modify the turbo boost like normal to fine tune.