I've heard from turbo opponents and proponents that turbo lag does exist, granted this is with an improperly sized turbo.
Now onto my question, is it possible to find a turbo setup through experimentation that brings in boost instantly like a supercharger?
I understand that backpressure and the size of the turbo have their hand in determining lag on your setup but is there something else that I'm missing in this equation?
When I talk about bringing on boost instantly I mean around 1000 to 1200 rpms. So is it possible or would the size of the turbo produce very little extra horsepower for as much as it would cost to create the setup?
Last edited by Ryanscamry; 01-29-2004 at 11:53 PM.
i dont think technology that will ever get to the point of instant boost from a turbocharger. the whole concept of a turbo feeding off exhaust gases means you give it a little rpm lovin and it in return spools the turbo and forces air back in.
the smaller the turbo generally the quicker the spool. but also that smaller turbo may not be in its efficiency range. you could have a 2nd gen dsm with a tiny little noisy t25. yeah that spools decently quick but at 16psi its not really doin anything. you have to sacrifice a little time when going with a larger turbocharger but running more boost well in the efficiency range is much more rewarding. there are ball bearing turbochargers that spool much quicker but also tend to empty the wallet quicker.
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1985 Toyota MR2 (4A-GTE)
1.8L 16 valve DOHC
TEDcomponents stroker kit, 4a-gze rods, 14b TDO5H, 440cc injectors, walbro 255lph fuel pump, and much much more.
From what I heard that can keep the turbo spinning even when u ease off the throttle. But you have to run rich and it causes All kinds of dmg to your turbo and exhaust. But that is the answer to your question. If I remember correctly, if u watch Initial D; in the movie he faced this guy with a black Lancer. And That guy kept bitching about how his "Misfiring system was superior, blah blah." And he had flames coming from his exhaust.
...then he gets his ass handed to him......
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Yeah I read a post from the Wraith about that, something about when you shift, instead of running at a lower boost in the next gear it keeps the turbo spooled up to the amount of you boost you had in the previous gear. He also said that you'll destroy the turbo within a year of running it like that and that you will shoot flames out of your exhaust. Insane.
I guess then from what I understand of twin turbos, you have a smaller one for the lower rpm range, and then a second, larger one for higher rpms to eliminate lag.
I've just read alot about it, and the lowest numbers I've read were that you can get boost from as low as 1800-2000 rpm, but i was wondering if you could get boost starting a little bit above idle? I suppose not though since the nature of turbos is to take exhaust and you don't get a whole lot of exhaust pressure at idle.
I feel like i'm using the wrong terms here or that something about my understanding of all this is amiss, I'm just not sure what. Thanks for the info though!
Oh by the way, when you said TWINCHARGE, did you mean supercharge and turbocharge or twin turbos?
Last edited by Ryanscamry; 01-30-2004 at 01:05 AM.
The setup I posted awhile back was found or can be found on the Celica GT4 WRC model... The production model cars dont have it working properly thought because the exhaust manifold isnt tapped striaght thru.
-As a recap:
Everytime you let off the gas your bov would release dense pressurized air to atmosphere. Not on the WRC model ( the non-production model used in the World Rally Chapionship) has 2 bov. Toyota calls this air asst.. One that releases to atmosphere and one the releases into the the exhaust manifold. What happens when you have unburn, expanded, and very hot hydrocarbons in a enclosed atmosphere and you hit it with a sudden blast of cold pressured oxygen ??? You have an explosion or combustion in your exhauts manifold where the explosion is used as a sudden power surge to spin your turbo ... Which in tails the flames coming out of the your tail pipe.
-To add to that:
another misfiring system is by playing with ignition maps and making the car mis-fire everytime you let off the gas from WOT. Thats why you hear the pop pop form the exhaust. And theres also another way were people over here call it a 2 step rev limiter and in Japan they call it a mis-firing system. Which is widely used for Import drag racing. This systems basic use is to have you launch from a dead stop at boost. You can have up to 7 to 10psi of boost off the line...
I'll try to look for my friends MR2 video launching with the 2 step ....
If you have the money, you can get rid of lag, and have power at idle...But it ain't cheap. As someone mentioned, it is possible to have a supercharger and turbocharger in the same car...If set up correctly, the supercharger would be used for low-end power, while a larger turbo would be used for big top-end power.
Also, I've seen some talk about electrically assisted turbochargers. Basically, they have an electric motor to keep the turbo spinning and providing boost when there is no exhaust pressure. It sounds like a nice idea, but I've never heard of anyone who has installed one, so I don't know how well it actually works.
Since nobody seems to be doing these 2 options, your other options are to minimize lag by using a bi-turbo setup and/or ball-bearing turbos. Anything using 2 turbos is going to cost big dollars. Not only do you have to buy the hardware, getting it to work properly would be a huge pain...If it's a 2 stage setup, you have to do the plumbing and build controls to not overspool your small turbo, and then use your larger turbo at higher rpms. I think a twin turbo setup would be easier, and more likely to work, but still could be difficult to implement.
Personally, I don't think turbo lag is a huge deal. I'm running a car with a rather large turbo that has a lot of lag if not driven correctly...But when it's driven correctly, power is on tap very quickly. Just keep your RPMs up, and if you're lagging, downshift. Pretty simple stuff.
Oh by the way, when you said TWINCHARGE, did you mean supercharge and turbocharge or twin turbos?
twin charging is one supercharger and one turbocharger...
Now there is a true twin sequential turbo setup ... Which is a smaller turbo force feeding a BIG MASSIVE turbo ... This setup will give you boost pressures way pass any production motor can handle except maybe Big ASS Diesel trucks... The boost pressures alone you can achive with this setup would make any boost-a-holic overdose. A low boost setting on this type of system would be 45psi and a high boost setting would be in the upwards of 90psi... So figure those numbers out... The only motor that Toyota has made to handle such turbos is the non-production 503E ( which I had the chance to buy one for $4500 but just let this one slip my hands). The 503E normally saw 90psi of boost pressures when in time trials where it was making well over 1200 to 1600hp, out of a 2.1Liter 4Cylinder...
well, theres one thing you guys that talk about lag this and lag that ... Lets not forget we drive FWD cars. Lag is our friend... How would you like to drive a 400whp fwd that makes peak power at 2000rpm ... You wouldnt be going anywhere anytime soon. You would just spin your tires, all day long.
I'll take my nice big turbo and have it full boost at 4000 to 4500rpm when the car is moving already...
Wraith man, you're killing me!! 90psi?!?!? Ahh, and you let it go at $4500?!?!?!? And 2.1L to boot?!?! Ahhhhh!!!!
Enough of that. Wraith, you my good man, are a genius. You certainly know what you're talking about. I wasn't serious about boosting at 1200 rpm, I was just wondering if has been done or if its being done. From what it sounds like though, in FWD cars, it would cost way too much and would be impractical due to tire spin.
Anyhow some good info there. I really appreciate it. I guess twincharging is being done somewhere or else no one would have brought it up, but this doesn't sound practical at all.
I think this whole idea of a supercharger giving boost right off the line is over rated anyways. Look at the ripmods system. It IS a turbocharger for all intents and purposes, just rather then using exhaust gases, it uses a pully, look at the dyno on that thing, more revs = more power. if the car went to 9000 it would make more power then it does now... a roots type or a screw type are still a little laggy, nothing is instant, they all function on the basis of engine revolutions.
Anyways, look at diesel fords in europe, the TDI jetta here, and even the 1.8 liter... they all have full torque almost instantly, and the reason is simple, they have small inlets which creates a bit of a bottleneck but forces more velocity and therefore the spool is all but instant. A well tuned t3/t4 with say a smaller 50 trim stage 3 and a nice 63 on the back, good size for a 2 liter up to 400-500hp while staying within effient range, can be running upwards of 15-20psi by 3500 rpms. Thats nothing to sneeze at... Bull boost doesn't mean full power anyways. it still maintains the stock power curve to some extent. I.E even if you get full boost at idle, your peak power will still be around 5000 rpms. If you really want lower lag systems you do things like VERY short intercooler piping (see signal drift setups), bad for compressor surge (no BOV) but almost no piping at all, just in on one side out on the other. Propper sized piping, a well tuned wastegate with a minimum of hose routing for boost controllers or anything else that diverts the flow of air. Plus low backpressure exhaust... the better the flow the easier the thing will spool. ITs all relative... and I think turbo lag is overrated to a large extent..
Oh, turbos.... if you don't push the gas hard and stay out of boost... you don't suck gas down. Its a nice feature
^^that is the same specs on my t3/t4....i'm lucky to be making around 300rwhp at 15-16psi.....lag is minimal....streetable to live with....i make full boost at around 3500rpm...i've driven cars with much bigger turbos and have absolute no power below 4000rpm...but when it finally spools....hang on....
One question for you... are you using a stock manifold or not? and if so whats the difference between the ct26 flange and the t3 flange? Minimal like the dif between fc3s and t4 flange or you need drilling or refactoring of some kind?
And I run a 57/63 stage 3 on my nissan, and it needs work right now. once I get it tuned I should be at full boost around 3200... must get freind to redo ecu programming to allow for my new stuff. SAFC is garbage!
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