I agree. If people want big time twisting torque off the go, get a turbo diesel truck. Low end torque yeilds nothing for HP and HP is what accelerates a car (HP = tq X rpm).

For those who feel there is little to gain in this particular case, take another look at the wide area from stock to 20G - an average 25 hp from 5K on up, quite a substantial area. Definately will make car faster

 

There is no doubt that it will make the car faster as it is a bigger, better turbo than the stock and will hold boost stronger until redline..

The only question is, is it going to be enough?

 

Also wouldn't increasing the onset of boost make the already problematic compressor cavitation (surge) problem an issue?

 

second graph looks much better...nearly 50whp gains up top. WOW! Those are the sort of results I was expecting.

David Buschur...the hype and talk of the 20g being significantly better than the WR was authored by none other than Al at Dynoflash

 

Well, that's just plain false. Bigger midrange torque means bigger hp in the midrange. This translates into a larger, more usable power band and better street feel, without the constant downshifting (think short track and autocross). Not everyone is constantly launching at 5k+ rpm on the street, nor does everyone want a dyno queen with a narrow powerband that feels like a marshmallow until 5k+ rpm. Different people have different wants and different goals.


Very much looking forward to it.

 

I would like to know how the DynoJet graph of the 20G spiked to about 30-31PSI looks. That is all.
And for those that haven't felt the stock turbo to hit at that spike - it feels like a sledgehammer!
I will continue to run my car this way with the blessing fro mthe alcohol god.

 

I would love to see a car taken to buschur, given a stock 9.8 turbo, dynoed, then a 10.5, dynoed, then a TME, dynoed, then a wr, dyno, 20g dyno, gt35r dyno. post all graphs. One common tuner, post afr, timing, knock count, for all turbos. Until this is done, we have no basis for comparison. Would help to be done in climate controlled facility, but that may be asking too much.

 

bump...just seeing where this goes.

 

Hmmm, ya think? LOL

I don't feel it necessary to split hairs to that degree. There is a market for a turbo that improves high rpm potential somewhat without sacrificing the midrange punch and spool characteristics. Such a turbo should be a direct swap, and be capable of putting an EVO squarely into the mid 11s with adequate supporting hardware and competent tuning. For many persons (myself being one of them), this is a realistic goal that can be achieved at an acceptable cost and with good overall reliabilty.

I feel Dave is onto something good here, and with a little more refinement and testing, he's going to have something with very broad appeal.

 

Did Buschur ever address the surging issue with the 20g? Or is it still considered to be a non-road racing turbo?

l8r)

 

The test of the stock vs. 10.5 has been done. We did that last winter. I offered to test the WR when all the controversy was surrounding it and was attacked for the offer, I was accused of just wanting to see it fail, which wasn't true.

I have since put a WR on our dyno with our Stage 4 kit and alky and 28-29 psi if I remember correctly.

There is also a graph already up for the 20G against a GT35r. So we have just about all you asked for, just have to search to find it all.

The 20G in it's current form still surges. The largest cause of the surge from what I am seeing a BOV's that are too tight. In the case of my RS the Tial BOV has the heaviest spring available in it, it surges.

David Buschur
www.buschurracing.com

 

After reading various threads about the 20g(and wr) vs a GT30r/GT35R style turbo I have come to my personal conclusion(s):

(keep in mind, my views are biased to daily driven vehicles)

Even if the turbo's are all the same price, the 20g/wr is still the cheaper option. I don't care what people say, by time you add all the additional pieces to actually put it on your car, the modified stock turbos end up cheaper.

Turbo repair and replacement is much easier with stock parts. Especially when your in the middle of nowhere. This really only applies to us who use our vehicle as a daily driver, not a weekend track car only. Track/weekend cars aren't usually used for long distance trips and the daily grind.

Horsepower is meaningless!!!

Let me rephrase that:
PEAK HORSEPOWER is meaningless!!!
It's all about the powerband. Especially if your are doing more then going to the drag races.

As various people have said - what good is 500hp, if you only have it for less then 1000 RPM? Personally being that I drive my Evo daily, trying to merge on the LA freeway waiting for a gt35r to spool is deadly, since once it kicks in, i'm pretty much about to rear end somebody.

Also (unless I go 2.4L) taking Turnbull Canyon (a really cool winding mountain road.. but lots of blind corners though )with a laggy turboed car is no fun. Transient times between shifts, kills your conering ability. This is where the modified stock turbo's rule.

Looking at the graphs, the 20g is a killer road course turbo even compared to the stock one. Yes there is some lag, but to me that looks like a smoother delivery (less sledgehammer like then stock) and more power on top where I need it.. The power delivery to me looks more like a N/A car then a turbo car. (If Mr. Buschaur's fix for surge works, that would just be even better.)

Considering that I've seen alot of gt30r-gt35r cars running high octane making 11's (and some 10's) on the average and you have the stock turbo's making 11's as well.. with less Peak Horsepower, you have to give prop's where props are due. (keep in mind these are cars with similar mods to it)

I'm not saying that a gt35r is a bad performer, If i wanted a killer drag car, i would be looking at a high revving 2.0, gt35r, possibly nitros assisted. But all around performance, gt35r is hard sell, when you get some slightly slower 1/4 mile runs, but all around response, performance, and control with a stock turbo (modified or not). But for those who don't want a drag only car (or a highway racer for that matter), this is the best compromise.

You drag a Race car, but it's very difficult to race a drag car on a road course (or one that has been specifically setup for Drag Racing)

To those who say it's not "cost effective", what is your goal for your car, what are you trying to do. 1200+ for 20-40 extra horsepower, isn't worth it (800 if you use your own core)? Then explain Porting your cylinder head for 20-40 extra Horsepower for 1600? Now if your building a drag car or all around highway blaster, it's not cost effective to you. But to those who want the Swiss army Knife of the Evo world (in regards to turbos) the WR and 20g are worth it.


As always, your mileage and opinions will vary.

Ignore me if you want, what I said is probably all crap anyhow.

 

LHB.. I've said the exact same thing in several threads, it seems that something is always lost in translation when everyone wants high peak numbers.. There are cars that are very quick using small turbos and under 400whp.. Its all about the powerband as we've all said many times..

I've said this before, what good is a big ******* if its flaccid until your almost done?

 

how about a tme or a 06 jdm spec?

nice numbers up top though. very intriguing.

 

MalibuJack:
I used to be one of those guys.. ARRR ARRR MORE POWER, Peak HP is GOOOD.
Then I found these forums, started searching, reading, and paying attention not only to what they were saying, but the results. And after looking at the GT kit's 1/4 mile times, I was acutally less then impressed. They were usually around .1-.3 seconds faster. Unless they were running C16 and heavily modified, the GT30/35's were not that impressive. Seemed like very little for the effort involved. Then I started to look at the Dyno Graphs and noticed the power curve... and had flashbacks to my 2000 Celica I used to have.

My 2k celica GTS was a pretty quick car, only problem was the power wouldn't hit until ~6300 rpm and redline at 8000. When you shifted you were just out of the powerband. While it was a fun car, it was annoying to have to rev it soo high just to get decent power out of it.

In Comparison, I test drove an RSX Type-S at one point. Despite the lack of power for the price of the car, it was a pretty awsome engine. Only ~200hp, but one of the flattest touque curves in existance. It was a PLEASURE to drive, complete power in any gear, no neck snapping boost or cam change. (just needed more power ). Quicker then you realize, power transition between gears was instantanious. Throttle modulation was execellent. I know why these cars hold there own in a road course.

To me, I would like to get to that level of drivablilty on my Evo, I belive it's possible to get really close (without going all N/A).
Having to rev it to high-heaven every time gets old fast. Once you add more power, but in a short spike, it gets harder to control and modulate, therefore less fun on the street. (Drag course however is a different story).

Again, my 2c, but i probably owe $1.50 in change.