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Engine Specific Info and Questions => IDI Engine => Topic started by: oldskool rich on May 21, 2008, 06:12:59 pm
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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?
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superchargers still have a pressure difference in the revs, as it revs higher, the CFM of air that it pushes increases.
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i hav a massive supercharger off a V8
should i run just the supercharger or a turbo too?????????? :?
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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
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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.
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turbo lag is a myth created by people that drive turbo chevy spirits
And 1.6TD's with T3's :roll:
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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:
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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.
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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.
(http://www.toycrazy.net/tech/pics/tcmod.gif)
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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?
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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
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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
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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 :D )
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would the vnt bolt on on the 1.6 manifold straight?
what is involved on doind thjis conversion?
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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.
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Juat a revision to the above: I dont think the AC pulley diferent on your engine is it? Just a longer belt. Use the ac mount holes in the block/bracket whatever to make a custom sc mount.
Also I would put the bypass valve before the IC to increase efficiency.
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thats the set up i was gona do although my T3 is scrap but ive just got my hands on a big ass turbo off a toyota supera, probly quite lagy will probly run that with the M45. do you think that set up would be better than vnt?
if so ill do it, if not ill be vnt hunting for a while :roll:
i just want a reliable daily that can kick ass on the quater mile :lol:
not asking much realy
probly not the right place to ask but wud the M112 be better suited for a petrol 5pot audi S1 engine?
gona start building one next year, not sure wheather to keep SC or flog it off
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If the 5 pot is the 2.2 and you want around 22 psi boost then it should be ok. You will need to use a big bypass valve on the petrol engine though, especially with such a large charger. Would make one hell of an engine if it was do-able though!!
If you look at the efficiency map of the turbo and find the start boost point on the 1.6, then drop it down by about 1/3 of max rpm you should get a rough idea of when it will start to boost in compound. If it is the standard supra turbo it should be ok, but be careful it is not a ceramic blade model as they cannot take more than 1 bar across them.
I reckon a properly sized compound system will be better then the VNT. You will have NO lag, and no surge to worry about on the little 1.6. Getting it working perfectly smooth for a daily would be more difficult than installing the VNT on its own though.
There are hundreds of VNT's!! Search on ebay.de for turbolader. The VNT garrett ones with the curved comp outlet are usually GT20xx. Just search the part number on the tag anyway. A GT17 may be better for the 1.6 though, like from the PD150/130 and newer 2.0 engines.
GT20
http://cgi.ebay.de/Audi-VW-2-5-TDI-Turbolader-059-145-701-F_W0QQitemZ320255480717QQihZ011QQcategoryZ61310QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.de/TURBOLADER-AUDI-A6-AUDI-A4-VW-PASSAT-2-5-TDI-155-180PS_W0QQitemZ270239461010QQihZ017QQcategoryZ61305QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.de/GARRETT-TURBOLADER-AUDI-VW-TDI-40-TKM_W0QQitemZ180246726254QQihZ008QQcategoryZ61310QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.de/Turbolader-Audi-A6-2-5-Tdi-von-Garrett_W0QQitemZ280228302479QQihZ018QQcategoryZ61305QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
GT17
http://cgi.ebay.de/NEU-Turbolader-VW-AUDI-1-9-2-0Liter-038145702G-J_W0QQitemZ150248799679QQihZ005QQcategoryZ61310QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.de/Turbolader-Audi-VW-130-PS-Passat-1-9-TDI-2-0-pumpe-Duese_W0QQitemZ350063117984QQihZ022QQcategoryZ61310QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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wow thanx very much, thats extreamly helpfull you realy know your stuff. i had already checked german ebay but didnt realy know what i was looking for. im doing a tdi project on the side and i need one of these big time.
i think im gona go for it with the super turbo plan, and then i can race the vnt tdi and see what is better.
btw its a 1.9 aaz but im guessing that wont make a differnce.
also why must i keep to around 22psi on the s1 engine?, yes its the 2.2. a reliable source tells me that these engines are factory built to withstand 1000bhp and the group B rally cars from back in the day didnt hav modified internals just tuned up to ***. any ideas on how much boost i could squeeze into one of these? also what do you meen by "bypass valve"?
sorry if i sound stupid, im still learning :oops:
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itchy trigger finger!!
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Its not a limit, the 22psi, just a guesstimate of a good number to run the SC at. It would support more boost if you needed it to! 8) With some seriously good intercooling, you might squeeze 30psi out of it on the 2.2 usefully.
Its pretty easy working out how to size an SC for an engine really. To get a ballpark figure just find how much air your engine is needing at a certain rpm:
(engine volume x rpm x volumetric effciency)/2
then the boost in psi you want is:
{[(SC displacement x drive ratio x rpm) / engine airflow] - 1 } x 14.7
Just change the drive ratio until you get the boost you want. If you needed say 1.5 drive ratio, your SC pulley should be 2/3rd size of the crank pulley.
The method above does not take into account SC efficiency (how much it heats the air) or heating due to compression of the air, but if you have a good intercooler (80% eff) you are still in the ballpark for sizing and drive ratio as long as you are running the SC in the right airflow range. You can check if you are by looking at the SC map like this one for the newer versions of the m112:
http://www.eaton.com/ecm/groups/public/@pub/@eaton/@per/documents/content/ct_128487.gif
One other way to check simply if you have the right SC is to see what it's max rpm is at the engine max rpm. Most wont withstand 14000 rpm (especially not the big ones), and if its not getting to 10000rpm its a bit oversized.
Most SC applications have an drive ratio of around 1.5, some have less but then don't have a great bottom end. Because the range of the usable boost on any SC engine needs to be the same as engine rpm range, they run right up to the inefficient high rpm's. This is when a turbo is ALOT better. Some engines like big V8's dont really need to much of a hand at the bottom end and can have low drive ratios nearer to 1, but its a waste of power driving the SC.
The bypass valve for the SC is so that the air is bypassed around the SC when you don't want it i.e. at low throttle openings. In a petrol car that is very important to avoid running lean. On a diesel you can worry less about it but you should really still have something in place. Alot dont though. It's because the SC is just a positive displacement pump and always puts out the same pressure ratio, not like a turbo which is load dependant (only spools up when you put your foot down). As diesels always run lean and dont have a throttle, you can just about get away with not having a valve for bypass if the boost controlling valve is set up correctly.
Anyway, a simple turbo into SC with big intercooler setup and external wastegate valve to control boost would make one quick 1.9 aaz!! It would be quick off the line and really torquey. It might be a bit *** to drive round town but good on the strip!!
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thanx, sum of that maths went over my head, but ill work it out.
gona give this a go, i aready had trouble not spinning in the first couple of gears just with my fuel mods and T3.
ive nearly got my mk5 6speed box running, this engine should be perfect.
cant wait 8)