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What makes a dsm un-streetable? Cons of very large turbo's?

16K views 155 replies 59 participants last post by  Boostingsx  
#1 ·
What makes a car un-streetable? Describe it!

Jon Doe over here runs an FP RED or any other very large turbo on the street. He loves it. Gas hog that eats motorbikes on the highway. Jack Average over there says "Its no fun on the street if its bigger than a 16G."

Have you run a large turbo? What made you turn down a very large Turbo? Or, why do you keep it?

I once owned a dyno tested 400 whp Ford Fairmont with a high compression 351W, hot cam, and a five speed transmission. That thing took ten minutes to warm up in the morning. It was a ***** to keep the carb in tune. The growl at idle it was scary. At 6,000 rpms it could break windows. It drank gas like a black hole drinks light. But, I still LOVED driving it around town. I was embarrassed to take a date out in it, or go anywhere I wanted to make a good impression..but I loved driving it. Bad manners don't bother me.

How big is too big? Why is an FP Red too big for the street?

Research tells me this: The larger the turbo, the more power it takes to spool it. The bigger the turbo the later full boost comes on. There are turbo's that don't start making boost until 5,000 RPM's right? But from 5 thousand to 8500 they are unstoppable.
How much boost does a green make at 4,500 rpms. How much boost does a red make at 4500?

I'm rambling aren't I. What is my real question? What is the biggest turbo that can be run without rediculous side effects in this application: a car that does not run nitrous, is driven 3 to 4 days a week mainly on the highway, has a built motor, and a driver who lives for power not comfort. I would like to know WHY this one is and that one isn't.

I wish I could ride with several DSM owners who have various turbo's like 20G's, Green's, Red's, L2-3etc's The mid south has an extremely low population of DSM's
 
#4 ·
SleepR DSM said:
How much boost does a green make at 4,500 rpms?
I get full boost (22 psi) on my Green almost right at 4000. I can run it a bit leaner and get it to spool a bit earlier, but don't feel like prematurely wearing down the engine. I've had this turbo on my daily driven '90 GSX for seven months now and absolutely love it. If I stay out of boost I can actually get some decent gas mileage. Once I get into boost though I can kiss that nice little feature goodbye:D
 
#5 ·
Why not...

Yeah it's all personal preference. I know of a few people who said their Green didn't spool fast enough for their tastes on a street driven car, yet their are others who love it. Of course, some of it depends on how you have your car set-up. Full boost at around 4000k all the way to redline at 8500k (I have DSM Link and a built head) is just fine with me LOL. And it's no dog at 3k rpm either ... it's not full boost but a Green at 15psi is nothing to sneeze at. What are you going to do ... downgrade to a 16G and lose all that power? No way jose. If anything do what the 300ZX guys do ... use nitrous to help spool the turbo faster. When done properly it's 100% safe and not that expensive either ...
 
#7 ·
SleepR DSM said:
How much boost does a green make at 4,500 rpms. How much boost does a red make at 4500?
Most likely full boost in both situations.
 
#8 ·
i have a 20g and it is a streetable turbo but you have to get used to sometimes not getting a jump from rolling starts and having to blow by that other car the neck breaking factor is fun for unsuspecting passengers. in other words YOUR call

Gsx T-rex
 
#15 ·
I have an L2R and I get full boost by 3500-3600 rpm.

I would say that the BB center cartridges are making many big turbos a lot more streetable. Not only does it reach full boost by 3500-3600 or so, but it start building somewhere between 2000-2500, I don't remember the exact number.

I can check some of my DSMLink logs, but in my opinion, if you want a powerful, big turbo, that is as streetable as possible, go with the new Garrett dual BB turbos. You won't be sorry.

Eric
 
#16 ·
what makes a car unstreetable is a 3 foot wing, carbon fiber antennae, and decals over 97% of the car. If you have a huge turbo then its unstreetable if its a 4 foot wing, carbon fiber antenna and mirrors, and decals over 92% of the car.
 
#17 ·
Wreckleford said:


Man, what are you talking about? My daily driver has a 16g and there is nothing unstreetable about it. I have even driven cars with 20gs and they boost threshold and lag didn't really feel any different to the 16 g.
He was obviously just joking.
I could tell a difference in spool between the t25 and the fpbig28, but anyone who felt the difference in accell wouldnt give a damn.
 
#18 ·
99GSTRaptor said:
I have an L2R and I get full boost by 3500-3600 rpm.

I would say that the BB center cartridges are making many big turbos a lot more streetable. Not only does it reach full boost by 3500-3600 or so, but it start building somewhere between 2000-2500, I don't remember the exact number.

I can check some of my DSMLink logs, but in my opinion, if you want a powerful, big turbo, that is as streetable as possible, go with the new Garrett dual BB turbos. You won't be sorry.

Eric
correct me if im wrong, but didnt ken (from indycore) say that his 1g with a 20g spooled quick than his L2R, but the new turbo pulled harder.

raptor can you compare you spool to your previous turbo (if it was the t25 then nevermind).
 
#19 ·
SleepR DSM said:
If an FP red (or simililar large turbo) can hit full Spool by 4500, Why is it unstreetable?
Because some confused people and the rest of TF&TF crowd believe any turbo should hit as quick as nitrous, reach full boost at 1K RPM while generating 50psi all the way to the redline. Turbo lag is extremely overrated by lousy drivers who can't shift fast enough without huge boost drop-offs and lazy tools that want to race from 40mph roll in 5th gear without downshifting. ANY turbo that can hit 20psi at 4.5K is perfectly streetable.
What makes a car un-streetable is its unability to run on anything but race gas due to extremely high compression, idle for more than five minutes without overheating or negotiate a speed bump without shattering the front bumper to pieces. ;)
 
#21 ·
very well said, taboo...


there are also other factors that contribute to "Streetability"...


if you take the exact same turbo in 2 cars, but 1 has shorter IC piping, a cyclone intake manifold, and 9:1 compression... obviously the latter car will be more streetable due to the shorter lag and quicker spooling...
 
#22 ·
Red turbo??

Anyone on this board have a red turbo driven on the street daily? I am thinking about getting one since its only about 200$ more for it than the green. I was thinking about getting the 7cm housing red, how much of a difference would that effect on spool and hp,opposed to the 8cm housing?
 
#24 · (Edited)
Taboo pretty much covered it................ Especially about the comment on turbo lag being over-rated. Yes its great to have a quick spooling turbo, hit full boost low in the RPM range, etc. etc. But the whole turbo lag issue is just out of hand anymore. I'm gonna give you a damn good exaple. Read on if you care to follow the story. Every body constantly bitches,pisses, moans, and groans about the Hahn Racecraft Super Turbo lineup. If your not familiar with them heres a link. www.hahnracecraft.com But back to the story. The complaints about these turbos are that the 10cm turbine housing is too big, too much lag, blah blah blah Set at 20 psi. a 3rd gear pull would bring full boost on at 3800-3900 RPM and this was with a 3" high flow catalytic converter still on the car. Without the cat it spooled about 100 RPM quicker. I dont see a problem with this. :confused: Another aspect that is over-rated is transient boost response. Sure its nice to have full boost on the ball bearing tubos when you hit that next gear but some of these new highbrid turbos are getting up there in price when you add all the bells and whistles. My suggestion to folks that are concerned about these issues.......... Learn how to drive your vehicle and learn to shift quicker....... Ahhhh, that felt good........ I'm done ranting off now. ;)
 
#25 ·
Taboo said:

Because some confused people and the rest of TF&TF crowd believe any turbo should hit as quick as nitrous, reach full boost at 1K RPM while generating 50psi all the way to the redline. Turbo lag is extremely overrated by lousy drivers who can't shift fast enough without huge boost drop-offs and lazy tools that want to race from 40mph roll in 5th gear without downshifting. ANY turbo that can hit 20psi at 4.5K is perfectly streetable.
What makes a car un-streetable is its unability to run on anything but race gas due to extremely high compression, idle for more than five minutes without overheating or negotiate a speed bump without shattering the front bumper to pieces. ;)
Buwahahahahaha, very well said compadre!
I'd also like to second the downshift bit. People who won't/can't/don't downshift can make the car unstreetable. Try a third gear drop at 65-70 mph and watch the motherfucker next to you wet his pants as the back of his head creates a dent in the seat as you hit 25 psi almost instantly. Lag, wtf?! ;)

Btw - A large turbo like a "Red," will make more power at 15 psi than your 14b will up at 19 psi. Figure that into your lag stories. Your RPM won't drop below 4500 rpm at the track when shifting so as long as that biotch is there by 4500 all is grand. IMHO, the real trick is finding a girl who'll get the passenger seat all wet instead of holding on for dear life. :D