Why? It makes sense to compare them as Engine wise the DSM's and the EVO are pretty damn close .

If this is true, where are all the fast 50 trimm evo's. I haven't seen many myself .

 

untill other people start testing these new greddy 20gs i wouldnt start talking about how much better of a setup it is over a dual bb 50 trim. it s hard to come to any concrete conclusion with only one magazine article from turbo magazine.

 

Yes, I would know, Ive had 3 (90, 91, 97) in the family and many of my friends have them currently. I love them to death and I cant wait to get another to mess with.

However, I already said why its a bad idea to compare a DSM vs the EVO. Engine wise, yes they are SIMILAR but very different. Different CRs, heads, intake manifolds, TBs, yada. The gearing is different, too. With the lower compression and weaker supporting mods and the fact that most 1Gs guys buy the NON BB versions can result in track times being not very comparable to EVO guys. We cant forget about powerbands. A 1G DSM making 420whp with a nonBB turbo compared to a 420whp EVO with a BB turbo is a big big difference in track times given equal drivers.

Honestly, I dont think many guys with 50 trims have even gone to the track. Remember, until AMS and Turbotrix kits came out (which was recently) there were just about none around. It was all GT30, GT35 kits. Turbotrix kits are selling quite well now and AMS just had a group buy. More are popping up. Im sure we'll see some great times coming soon once they are all installed the ready to go.

 

According to "JUN EVO" a gentleman on this board.. it hit over 700whp... which is what i'm saying... the turbo doesnt normally even KISS this hp.. let allow 100 under it..... although i dont know how real JUN EVO's numbers are bc i dont recall even seening a Dynograph.. not saying it's not real either though.. i mean look at at the JUN cams compared to HKS .. kicked the **** out of the hks... just imagine a whole motor build by them....... ::shruggs:: i dont know ... but i do know JUN makes stupid cars.. and ur right... we need to wait for the new track times from the BB 50trim and from greddy's 20g to really see what's goin on...

also something to think about .. when u are compareing the turbos u have to look at what your comparing them for... wheather it's Highway or 1/4 or AutoX ... i think that's important as well

 

I've run both the (old) 20g and 50 trim on my 2g. While not an EVO, it's irrelevant for the sake of comparing the two turbos, and regardless of the differences between the DSM and the EVO the max power attainable will be the same with either car assuming they are turbo-limited (<operating phrase here ).

I honestly get a kick out of all the debate between the two turbos. There is 2 lbs/min difference between them! That's about 20 hp. The 20g consistently maxed out at 48 lbs/min for me, and the 50 trim maxed out at 50 lbs. It was impossible to tell the difference in my case. To make it even more of an apple to apple comparison, I ran them both with a TDO6H turbine wheel. The 50 trim did take slightly longer to reach full boost. IIRC, the 6H 20g reached 25 psi by ~3600 rpm, and the 50 trim was ~3700, in third gear. While both turbos performed similarly, I ran a little faster on the 20g.

I've also compared the 56 trim GT40 wheel (from the 35R) in both BB and conventional versions. Both reached 25 psi at 4400 rpm. No difference. I also couldn't tell much of a difference in transient response. Based on this I'm not a huge ******* swinger for BB turbos. The only real advantage in my opinion is the lack of a thrust bearing, which I tend to kill quickly because I run all my turbos completely maxed out (no signal line to WGA) at the track, and close to it on the street. Well, except for the T67, I never got closer than 10 lbs/min from its 75 lb rating

I also get a kick out of all the poeple that say they are considering a 50 trim OR a gt35r. They are completely different turbos! At max flow ratings of 50 lbs/min, and 65 lbs/min, the 35r is 30% larger than the 50 trim! We're talking about a 150 hp gap between the two. I don't get it. In my humble opinion, anyone making this comparison either doesn't know the limits of the two turbos, or doesn't know what it is they're looking for.

Another interesting tidbit I'd like to share, since I also see so many poeple upgrading turbos but not raising boost, is that if both turbos are within their limits, one is not going to make significantly more power than the other at the same boost. I know this shouldn't be news to anyone, but I've been seeing a lot of this type of thinking lately, especially on this forum. As an example, from my own experience with the stockpile of turbos I've run, take the 20G and the 35R wheel. I ran them both in the same turbo otherwise (6H). At 25 psi the 20g provided ~47 lb/min of air. Just about maxed out. Went to the 56 trim, and airflow remained exactly the same. ETs at the track however got significanly worse, since time to boost went up dramatically. 3600 rpm vs 4400. By utilizing no lift shifting the gap lessened, but the larger turbo was still slower. Trap speeds were almost identical. And as in interesting side note, the same 56 trim turbo on a 2.3 liter reached the same 25 psi by 3700 rpm (!), and airflow went up significantly, making the car much faster, naturally.

But enough of my rambling. The moral of the story is that you need to know what you are looking for when chosing a turbo. While the 20g and 50 trim are very similar in size and both do very well on 2 liters with proven track records, there are better options out there IMO. The 35R is a huge jump, but thankfully there are a couple GT30 options that bridge the gap. The smaller tends to run about 52 lbs/min, hardly an improvement but BB for those that get wood from it, and the 3076 is good for about 55 lbs/min. A healthy 50-70 hp more capacity than the 50 trim/20g. Unfortunately the only thing between this and the 35R is the 60 trim and 60-1, neither of which I find very desirable for a 2 liter, though the 60-1 in FP Red form has done very well in DSMs. I've never heard of one on an EVO however.

One more thing. The EVO 8 turbo maxes out at 43 lbs/min. Making a 20g about 50 hp bigger, and a 50 trim about 70 hp bigger. Again this is at max capacity, higher boost required. Not a huge improvement for the money, but for the many people stuck in the very low 12s or very high 11s on the stock turbo, this is enough to get you kicked out for lack of a roll cage And for this reason alone I have considered running my favorite pump gas/street turbo of all time, a full TDO6H 20g. I have run these from SBR in the past, and I especially like the one they made with the larger compressor cover. But, more likely, I'll go for the 3076 for a little more capacity, lack of a thrust bearing for me to ruin, and what I feel is a better match to a 2 liter and my current goals (2 literes at 100% VE, 30 psi, 8000 rpm, and some other assumed variables will move 55lbs/min). Anything over about 55 lbs/min really needs a stroker for the average guy to make the most of it.

 

Nice write up Kevin. That should help people understand.

 

I think a lot of people would beg to differ on that. If the BB turbos werent anything special, no one would be using it. My brother has a GT3076 BB and my best friend has a non-BB 50trim. Completely identical setups, both 1Gs, same CR, stock heads, intake manis, 2g manifolds, etc and the 3076 has very noticeable advantage in spool-up and transiest response. Not to mention the 3076 is even bigger.

GT35R non-BB and BB spooling the same? I find that extremely hard to believe. Id love for Buschur, AMS or someone to chime in on that.

I agree with just about everything else you said though

 

I would like to Disagree with this. 20PSI on the 16G Vs 20 PSI on a 50 Trim is a HUGE difference in power. People are maing 420++++WHP on the 50Trim on pump 93 and no alky. You cannot do that with the 16G or even the BR 20G. Same goes for the GT35R and the GT3076R


We have the 3065, seems to be a promsing Street turbo.

 

I don't see anything in your post that leads me to believe the difference is from the BB cartridge. They are different turbos entirely. Every single piece involved is different

I always welcome more input, it's very possible others have had different results than I have had. But I saw this with my own eyes, and with plenty of feedback to spot differences between the two.

Thanks

You missed one of my key disclaimers on this point The 16g in your example is maxed out at 20 psi (assuming cams), so it is no surprise that the 50 trim will make more power. Lower the boost a little (16Gs tend to max out at 19 psi for EVO varieties, and even less for the smaller ones, with cams and the usual mods) and they will be the same. I made this same comparison as well, with both turbos within thier limits. Airflow was the same. ETs were slower on the 50 trim. Of course once the boost went up the 50 trim started to earn its keep

Any gains specific to pump gas, and with the turbo not maxed out, can be credited to the difference in the hot sides of the turbos. The 50 trim is going to have a larger turbine side than the 16 or 20g in your example. A larger hot side will increase VE, lowering the amount of boost it takes to run a given airflow (power), or one could also say the opposite is true, more airflow (power) is possible at the same boost. This is ALWAYS a good thing on pump gas, since boost is heat, and heat is knock, and pump gas power is almost always knock limited. This is why mods like cams and SMIMs are so beneficial on pump gas, but won't raise your race gas power if you are maxing out the turbo. They will just lower the boost it takes to get there. For example, a 16g will max out around 19 psi on a 2 liter with cams. Without cams it will be more like 24 psi. And by max out I mean the compressor's flow has reached it's limit, and higher boost can not be sustained at redline/airflow per time peak.

On race gas with maximum boost these arguments become non-issues. The only substantial factor in power production from the turbos point of view is the compressor's flow capacity. So your example is not wrong, but it is a different point than what I was getting at in my previous post.

 

I did a back to back BB non-BB 57 trim turbo setup years ago. if you lay into it at 3000rpm, they both hit 25psi at 4100rpm. You couldn't tell which turbo was on the car. Transient response on the other hand was greatly improved. That is to say when you shift at 7000 and lift the throttle to do so, the next gear lands at 5000rpm. At that rpm there is plenty exhaust to be at full boost. The BB turbo gets back up to full boost much quicker.

In the first example the turbo is ramping too slowly to notice any gain from having a bb shaft. The friction from plain bearings and a thrust washer is negligable during spool in that instance.

 

I was just considering the transient response after reading your post. I bet the main reason I Didn't see a difference is that I no lift shift every gear with a 6k rpm stutter so it holds boost anyway.

 

wait so a 50 trim is only worth about 80ish hp over my stock turbo?

 

Yeah cams but certainly isn't maxxed out at 20PSI, I run more then that on my pump gas 9.8 Hotside and it holds it quite well. Hell evn run the 50Trim at 15PSI and the 16G at 15PSI and the 50 Trim would make more whp as more CFM's and better efficency.

 

A stock turbo MAY make close to 400WHP on race gas with MANY mods and even then just touch it for an instant and then fall off. The 50Trim is a 400WHP pump gas turbo easilly and will hit 500WHP maxed out, the 50 Trim is a 100WHP gain.

 

How was this statement validated? I'm interested in the numbers, wether it be dyno, track, or even just mass airflow.

I would stay far away from quoting anything to do with CFM, or any other volume measurement, and stick to mass flow measurements. And at 15 psi with those two turbos and a front mount intercooler, efficiency is irrelevant.