Nissan also has a twin-turboed 300zx. Seen videos of them running with cobra with a simple aftermarket intake and exhaust.
By intake I mean like a K&N system.
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i think the idea with having a turbo and a roots supercharger is the the supercharger gives the power down low to make up for the lag until the turbo is spooled. this is just my theory not a fact.
thats exactly what its doing. vnt basically eliminates all turbo lag, but even with vnt improvements it still really isnt a longer term viable part.... although i think some diesels are now coming with them like the cummins, so who knows maybe there better and wont break as much.
i'd like to know the cost break down between vnt warranty repairs vs. increased manufacturing costs and complexity of the compound turbo/super charger setups.
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Nissan also has a twin-turboed 300zx. Seen videos of them running with cobra with a simple aftermarket intake and exhaust
This is not what we are talking about, its true the 300zx uses two turbos the they are not is series just parallel.
The 3rd gen RX-7 uses two turbos but they are diff sizes and the computer switches the smaller turbo off as the motor rises to a larger turbo to help prevent the torque of the rotary being so low.
All of our Titan crash fire trucks on post use the compound roots/turbo system and they are very reliable.
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i've seen pictures of a hyundai tiburon with a turbo, supercharger, and nitrous all at once. it was a show car though so i doubt it was for performance reasons haha.
unless the guy figured he needed the turbo's to make up for the parasitic power loss caused by the supercharger, and then decided he needed nitrous to help the turbos spool faster
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thats exactly what its doing. vnt basically eliminates all turbo lag, but even with vnt improvements it still really isnt a longer term viable part.... although i think some diesels are now coming with them like the cummins, so who knows maybe there better and wont break as much.
i'd like to know the cost break down between vnt warranty repairs vs. increased manufacturing costs and complexity of the compound turbo/super charger setups.
hmm eliminates turbo lag?? i dont think so... it reduces it, yes, but for example the new duramax has a VNT... and still is over 3 seconds of lag from a standing start.
Superchargers and turbochargers still are orders of magnitude different in response time, VNT or not...
VNT's are expensive and are much more prone to breaking.. The technology is great, but with complexity comes cost and with 'complexity and high temperatures' comes reliability issues... The technolgy is great but its definately not the "end all, be all" of boosting..
when looking at the diesels, also consider the amount of volume the "compressor" has pressurize, its going to take time to boost regardless of actual turbo lag time.
my experience with vnt was the shelby daytonas with vnt. and those thing came up on boost instantly, there wasnt any perceivable lag time.
but ya, they were prone to breaking ... alot ...
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Detroit diesel has been doing this for years. It is not a new thing the 6v92 and 8v92 have a blower on the intake being fed by a turbo.
I fished on a boat for awhile with a dual charged 1292, monster engine! with the lil 2cyl generator going we burnt 20-22gallons an hour. and between the valve train and the whine now I cant hear really high pitches to well..
That company is located here in Albuquerque NM! they basically wanted something cool differnt and letal ive seen the 1600hp set up and WOW! the use of the two types of FI is to basically mold the power curve turbos have a NA look but advanced in RPM SC have a sloping look think about it off idle monster torque and good solid mid and top end with turbos supplying the boost by force feeding the SC. They wanted something to perform well at this Altitude and higher ie denver well that was from the donkeys mouth so...
Detroit diesel has been doing this for years. It is not a new thing the 6v92 and 8v92 have a blower on the intake being fed by a turbo.
this guy's got it right.
Basically, a roots-style blower can only grab N/a air up to a certain rpm of efficiency. After that, it simply cannot pull more air because of its design. It is essentially a boost multiplier. (which is why an 03 cobra has so much torque, but a comparably weak high end, and why a centrifugal blower-style car will not have the guts in the low end, but will fly by in the high end-it takes time for the centrifugal to build boost, much like a turbo).
With a turbocharger and supercharger, the turbo is used to compress the air and force it into a roots-style blower so it can multiply the boost and achieve an incredibly high compression ratio. This is mainly used in diesel engines, like redta said, because they are compression-based engines.
sorry if the question was answered already, but I just read the first few posts
Could you use a centrifugal supercharger in front of a roots instead of a turbo? This wouldn't exactly multiply the boost but instead supply more top end, or am I wrong? Secondly, could one use a twin screw instead of a roots type supercharger?
Could you use a centrifugal supercharger in front of a roots instead of a turbo? This wouldn't exactly multiply the boost but instead supply more top end, or am I wrong? Secondly, could one use a twin screw instead of a roots type supercharger?
Yes a company in Oz rana GTO with a maggy and a vortec blower on there. they modded the vortec to allow some air to be pulled 'past' the Centri. they didn't run an intercooler before the Magy though....
Anyone else think this dyno could be duplicated with some nice twins?
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Couldn't you run a small turbo that would spool. Instantly. But feed it from a centi supercharger so at high rpms the small turbo would not be limited by flow cause it would be force feed by the supercharger. Making it act like a much bigger turbo ?
Anyone else think this dyno could be duplicated with some nice twins?
The Hellraiser kit if anything would be more for show or just for bragging rights. MM&FF tested it vs a twin kit and the twin kit (same psi) owned the hellraiser.
The Hellraiser kit if anything would be more for show or just for bragging rights. MM&FF tested it vs a twin kit and the twin kit (same psi) owned the hellraiser.
That is why "compound boost" is brought into the question. More boost virtually means more power.
Of course the twin kit made more power than the hellraiser at the same boost. The supercharger at this point would just act as a restriction. The power increases when the boost is compounded to high psi levels.
Yes that why im thinking. lets say engine is a 402 with with dual 60 turbos should spool pretty fast right ? but be little down on max power cause the small turbos can only flow so much air. but if a supercharger is pushing 15 psi of air to the turbos they should they now be rate for double the hp now. turbos could be use to now compress the air to 30 psi.
The Hellraiser kit if anything would be more for show or just for bragging rights. MM&FF tested it vs a twin kit and the twin kit (same psi) owned the hellraiser.
Not low down though! i head there was over 200bhp more lower down the RPM band than the twin turbo only kit......
Yes that why im thinking. lets say engine is a 402 with with dual 60 turbos should spool pretty fast right ? but be little down on max power cause the small turbos can only flow so much air. but if a supercharger is pushing 15 psi of air to the turbos they should they now be rate for double the hp now. turbos could be use to now compress the air to 30 psi.
Rish, hate to put a downer on yuor idea, cos it sounds good! but can your motor take 30.psi???
be nice for someone to try all these ideas though.
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