20g - Where's the fast ones

[pboglio]

Since when does 1 psi difference at 500cfm equal 5-7% difference in mass airflow a 500-600 cfm?

I've swapped from a 1G maf to a MAFT in blow through and saw no difference in boost by redline with my 60-1. How can your wastegate actuator not see that extra 3 psi?

Simple. If my intake restriction is 1 psi, then my compressor sees 13.7 psi not 14.7 psi. Your airflow will increase by 14.7/13.7 or 7%. Since my Garrett compressor was rated for 13.95 psi atmospheric, my compressor theoretical increase would only be 14.7/13.95 or 5%.

This is only going to work if your OUT of compressor, at the limit and your boost is dropping off. If you have a 600 h.p. compressor, and your only pulling 50 lb/min of course your not going to see gains. If your pulling 60 lb/min then you'll increase it at least by 7%, more like 10% since at that flow rate the 2g MAF won't be dropping 1 psi of restriction, but more like 1.5 psi.

My logs dated 12-1-07 and 12-23-07 can be compared, for instance the 2nd gear pulls which illustrates what I'm talking about pretty clearly. I'm almost out of compressor and pulling the 2g MAF completely opens up the top end above 6000 rpm on that particular log. In fact, I haven't reached the power potential yet because I'm still inching my boost levels up even higher to take advantage of the lack of restriction.

By my calculations, I should be able to reach 390 h.p. at the crank, which is only 16 h.p. away from my current 374 h.p. (DSMLink estimated). I've already picked up 20 h.p. due to the 2g MAF removal so far. Right now I'm venturing into the 25 psi range at 6000-6250 rpm which is what I calculate my engine needs to reach that h.p. level.

 

[dsm-onster]

Great explanation. How did you come to the '1 psi drop at 500cfm'?

I still wouldn't worry about a 2g maf when it comes to air flow. That loss means nothing if you've properly sized your turbo. You certainly show the real advantage of speed density. 7% better w/ maxed out turbo.

A 20g is not maxed out at 25 psi on stock shortblock, even cammed to hell, and stock rev limit. 0.31 m^3/sec (660cfm) at 20 psi and at only 130K rpm. 144K rpm is definately attainable with this compressor as it has the same major diameter as the evo3 16g. And clearly it can be seen that the map would draw out to .33 m^3/sec or 700cfm. This is 50-trim territory (47-49 lbs/min).

 

[pboglio]

Great explanation. How did you come to the '1 psi drop at 500cfm'?

I pulled the data from some "DSMtalk" thread. The guys that designed the MAFT posted fairly detailed pressure loss values for the 1g, 2g, and GM 3" MAFs and different flow rates etc. when they first came out with the MAFT. I used that data. I never bothered to measure it myself. I have done fairly extensive pressure drop testing of my STi intake system though and I can easily believe 1 psi thru the 2g MAF at those flow rates. Who knows

 

[FonZ454]

Yep, I'm knocking in that log. I'm also knocking in this log too, but I'm also running an aggressive timing curve which is giving me my power gains.

Wouldn't you think that your aggressive timing curve is giving you that knock?

 

[arash15]

Wouldn't you think that your aggressive timing curve is giving you that knock?

There is no aggressive timing curve because once the knock sensor sees knock, it begins to pull timing. His statement is contradictory. Not the smartest way to tune the engine. For example if he's running 19* of timing at 6500 rpms and the knock sensor is at 2.0 degrees, then hes actually running 17* of timing.

 

[arash15]

Yep, I'm knocking in that log. I'm also knocking in this log too, but I'm also running an aggressive timing curve which is giving me my power gains. This log is on the 2g MAF, which is dead stock in every way. I'm pulling 37 lb/min in 2nd gear, kind of hard to argue that fact. I'm not quite at the limit of the T28 though under these atmospheric conditions. At these temps a T28 would pull about 39 lb/min. Pull the MAF and run a VPC as in my other log and that limit would go to 41 lb/min.

I am definitely running more than my previous 37 lb/min since I'm pulling about 20-30 more peak h.p. on the VPC setup, but less than 41 lb/min, what exactly that value is I have no physical way to tell at this point due to the VPC's airflow cap value. The VPC makes airflow values impossible to decipher, at this point I fall back on in gear acceleration times and w.h.p. estimates for tuning purposes.

My props are correct, trust me. I'm running "massively" heavy 16" steel wheels on heavy 215/55 Blizzak snow tires on a full stock weight 2g AWD. I'd be pulling faster times on the stock 17" rims if I had them installed. The w.h.p. is what it is, just set the drivetrain value to 0%.

Yes, the HKS VPC needs calibration badly. I don't have DSMLINK V2 otherwise I would have tweeked the VE maps to compensate for the VPC.

Your coolant temps are VERY low. 135* is not normal, and hopefully its a bad sensor. Do you warm up the car before WOT pulls? Having a non calibrated VPC is going to reflect on false airflow values, just as a GM MAFT setup that isnt calibrated would. That is why so many people using the GM MAF setup claim to be running XX lbs/min and complain why thier cars are slow, and why thier 70-90 mph time is so high. In this log your aggessive timing settings arent helping anything. At 6k you increased the timing settings +7 over the stock timng curve. Thus you are running 21.4*, then you are knocking 1.8* so you are actually running 19.6*. Now if you readjust your timing settings according to knock. Set timing +5* @ 6k and do another log and youll probably notice no knock. Once the car begins to knock, its going to continue to knock through the entire pull.

 

[The_EE]

I am going out to the track with my 20g in January and can post some logs and numbers. Last time I went to the track I ran a 12.62 @ 113.23 and that was on a tired stock motor ( 132,000 miles, 130 compression at the very most taken a year prior ), blown turbo ( didnt know it was blown until I check for shaft play, the 5200 full spool was an indicator ), blown clutch and broke an axle in 2nd gear.

Now that I have the turbo rebuilt, new fully built engine, new clutch, new tires, new axles I am shooting for the low 11's and possibly high 10's. DSMLink has proven to be pretty damned accurate when it comes to horsepower numbers on the dyno and the last log on the old engine was showing 451/401 on 22* running 110. I am shooting for 25* or so on the new setup and hoping to pull near the 500hp mark on the turbo.

01-05-08 we will see what happens.

 

[CanadianTSi]

While a 20G may only flow 42-44lbs/min I bet you it will out ET a Bigger Turbo flowing a couple lbs more.

Quick Boost Recovery is nice on smaller Turbo's

 

[Black_Bullet]

While a 20G may only flow 42-44lbs/min I bet you it will out ET a Bigger Turbo flowing a couple lbs more.

Quick Boost Recovery is nice on smaller Turbo's

NLTS will take care of that.
And i thought the true 20gs flowed a little more than that. Ive heard of a few ppl getting 45-46lbs out of them? Maybe misinformation; idk.

 

[TurboAnything]

I think theres a lot of hype on the 20g. It is a amazing turbo but i don't see anyone making 500hp or even close. Properly tuned a street car can get maybe 430hp on a tdo5h and 450 on a tdo6. I look at it this way i built a 3065 car this year too and it was final tuned at AMS and at 28-29psi it only made 505hp and 420tq. Now that is a much larger turbo both cars were on 100 octane. But if the a 20g car was lite enough it could be a 10 second car.

 

[Black_Bullet]

If i upgrade from my evo3 i was thinking it be either out of a BB fp3052, a true tdo6 20g, or a gt3076R Ive never been looking for a specific horsepower number in my goals but more so a 1/4 time and speed. Which realistically all three of those will reach my goal which is only 125mph traps doing mid 11s. I can manage 115mph traps on race gas with the evo3 already due to my cars light weight ( and thats on stock engine without cams.). So thats how im sure i can reach my goals with either of those 3 turbos so i guess end question would be which had quickest spool for street purposes, and not only fast spool, but quick transient boost response and also good/ long reliability at boost levels between 20-25psi. Wonder which makes best/ easiest pump gas power despite I plan to run e85 once it comes local to me..Whenever that is?....

 

[dsm-onster]

I think theres a lot of hype on the 20g. It is a amazing turbo but i don't see anyone making 500hp or even close. Properly tuned a street car can get maybe 430hp on a tdo5h and 450 on a tdo6. I look at it this way i built a 3065 car this year too and it was final tuned at AMS and at 28-29psi it only made 505hp and 420tq. Now that is a much larger turbo both cars were on 100 octane. But if the a 20g car was lite enough it could be a 10 second car.

Pump gas and a td05h turbine do not mix at 400whp. I don't believe that anyone is 'hyping up' the 20g . 450whp on pumpgas is quite respectable for a bolt-on. Pumpgas and th td06h is definately doable up to 450whp.

NLTS will take care of that.
And i thought the true 20gs flowed a little more than that. Ive heard of a few ppl getting 45-46lbs out of them? Maybe misinformation; idk.

This is not misinformation. Even the MHI compressor map reveals 660cfm. And the map doesn't display the 144K rpm range. The 20g compressor is comparable to the 50-trim compressor.

 

[FonZ454]

There is no aggressive timing curve because once the knock sensor sees knock, it begins to pull timing. His statement is contradictory. Not the smartest way to tune the engine. For example if he's running 19* of timing at 6500 rpms and the knock sensor is at 2.0 degrees, then hes actually running 17* of timing.

I know.

What I am saying is that he says he is running an aggressive timing curve. But it's filled with knock. If he backed down the timing so it doesn't knock, he could potentially run the same timing he currently is (because it's knocking and pulling timing) and be better off. He should definately be caring about making the car knock-free and not knocking, but aggressive.

I think theres a lot of hype on the 20g. It is a amazing turbo but i don't see anyone making 500hp or even close. Properly tuned a street car can get maybe 430hp on a tdo5h and 450 on a tdo6. I look at it this way i built a 3065 car this year too and it was final tuned at AMS and at 28-29psi it only made 505hp and 420tq. Now that is a much larger turbo both cars were on 100 octane. But if the a 20g car was lite enough it could be a 10 second car.

I wouldn't call them hype. It's basically the most proven turbo out there. As of recent years people have been going with HUGE turbos and not always beating 20g times. Like said earlier, some of the 20g times are hard to beat, And it seems like some guys on gt35r's and bigger are having hard times hitting 10's. And like dsmonster said... 400+ whp out of a small td05 wheel will be hard to do. FP's bolt on turbine housing flows much better, making numbers easier to get.

 

[Black95TSIawd]

There is no aggressive timing curve because once the knock sensor sees knock, it begins to pull timing. His statement is contradictory. Not the smartest way to tune the engine. For example if he's running 19* of timing at 6500 rpms and the knock sensor is at 2.0 degrees, then hes actually running 17* of timing.

Thats exactly what he is asking.

I'd rather set it to 17 degrees and get no knock.

 

[pickens]

I don't think we need to even debate the -05h wheel (clipped or unclipped). The debate if any, should be around the -06h wheel. But the compressor is what will really determine airflow which is the same in both turbos.

I gotta admit, I always wanted a 20g and may just pick one up just to see what it can do in a full weight 2g.

 

[dsm-onster]

I don't think we need to even debate the -05h wheel (clipped or unclipped). The debate if any, should be around the -06h wheel. But the compressor is what will really determine airflow which is the same in both turbos.

I gotta admit, I always wanted a 20g and may just pick one up just to see what it can do in a full weight 2g.

Well, it's better to say that a turbocharger's flow potential is really determined by the lowest flowing element. . .

 

[Black_Bullet]

Well, it's better to say that a turbocharger's flow potential is really determined by the lowest flowing element. . .

An entire engines flow potential is determined by the lowest flowing element...

 

[pickens]

Yes, in this case the the compressor wheel is the limiting factor. A clipped 05h or -06H wheel can outflow a 20G compressor wheel all day long.

 

[pboglio]

Just wondering what your 70-90 mph times are, what kind of IDC do you see & do you have any 1/4 times (with 60ft & mph)? Those flow numbers seem to be on the high side with that kind of boost (this is running 20 psi?) for the T28, especially since it looks like your running a stock 2g head & intake mani with 264 cams.

Here's a 3rd gear pull I did Christmas Eve. I tightened a few hose clamps down and added 1* of timing from 5500-8000 rpm. That did the trick as I was able to hold a solid 23psi well past 6000 rpm, and 24 psi near 5500-5900 rpm. My fuel pump is slowing down from the high boost levels, so I actually picked up some power from the motor leaning out a bit.

The 70-90 mph time is 2.13 seconds or so. The power leveled out at 403 h.p. crank/351 w.h.p., not too shabby for a tiny little T28 Take the DSMLink estimate for what its worth. This is on a ported T28, essentially a Big T28 with a slightly more restrictive turbine wheel. Big T28s usually pull another 10-15 h.p. or so from what I've researched. I got a little knock near redline, but I think it might have been a mechanical noise that set off the knock sensor. I pulled 80-120 mph with ease on the expressway. I would have buried it to 155 mph but my Blizzak snow tires would have disintigrated on me

Talking about turbine wheels, I thought my small T28 turbine wheel might have been limiting my top end. But apparantly that wasn't the case, I ran out of compressor first from the looks of it. I'm gonna skip the 20g entirely and go with I think a GT3071 ball bearing turbo.

I included a log of a very quick 20g running 11.83 @ 121.5 mph. for the sake of comparison, as well as that same 20g running 20 psi pump gas. From those logs, I'm faster than the 20g when its running pump gas, and only .19 second behind it for all of 3rd gear when its running 25 psi on racing fuel. Sorry for straying off the 20g subject. Cheers.

Gene Boglio
97 GSX

 

[JOEY A]

Stock 2g intake manifold, Stock 2g cylinder head, Stock 7-bolt block, Stock 2g pistons, ARP 2g head studs (11mm), HKS 264/264 cams

Cold/ram air 4" i.d. duct, K&N fipk, Stock 2g maf, RRE 2.25" maf/turbo intake pipe, Cut cbv return pipe, ADFX fmic (23"x10"x3") extruded core, ADFX 2.5" aluminum upper/lower i.c. pipes, ADFX 2" s.s. t28 j-pipe, MHI pre-95 cbv, Dejontool cbv stop leak pilot valve, MHI 60mm t-body, HKS/custom 2.5" t-body elbow, Denso 150 lph fuel pump, Denso 660 cc fuel injectors, Fuel pump rewire #10 awg, Ported 2g exaust manifold (7cm collector and knife edged divider), FPT28/28 turbo (62trim compressor/79 trim turbine), 7cm ported turbine inlet & bell ported turbine outlet, Ported/radiused compressor inlet, Ported 2g O2 housing, HRC 17psi wastegate actuator, Alamo 2.5" mandrel bent s.s. downpipe, Buschur 2.5" testpipe, Thermal R&D s.s. 3" catback w/Borla 3" mid muffler.


Sounds like a very very well matched setup you have there

 

[Black_Bullet]

pboglio; what do you run at the track? I didnt think the t28 flowed what your saying so easy,
and what were the 20g cars mods ? For only 121 mph traps he still had a lot left to go in that turbo unless he was extremely heavy.

 

[dsm-onster]

An entire engines flow potential is determined by the lowest flowing element...

Exactly. The turbine almost ALWAYS is. If it's not, then the individual components weren't chosen wisely.

Yes, in this case the the compressor wheel is the limiting factor. A clipped 05h or -06H wheel can outflow a 20G compressor wheel all day long.

One can clip the he!! out of an 05h turbine, but the exducer is still the same diameter. An 06h turbine is wider. A 20g can flow 47-49 lbs/min. I've never heard of any clipped 05h turbine coming close on a conventional setup. Anything short of making an 05h unusable will not yield more flow than the 06h wheel. In the case of a td06h turbine, yes, the 20g compressor is the limiter.

 

[pboglio]

pboglio; what do you run at the track? I didnt think the t28 flowed what your saying so easy,
and what were the 20g cars mods ? For only 121 mph traps he still had a lot left to go in that turbo unless he was extremely heavy.

I never ran my car at the track, would like to though. Yep, T28 flows pretty good considering what it is, been telling people that for years but nobody ever listened

Yeah, that 20g probably did have a lot left in it. I think that car had a Buschur 20g, HKS 264/264 cams, 25 psi on C16, and a 1g head. They are old logs I picked up from the DSMLINK forums. They looked interesting cause the 20g owner had both pump & race gas logs for direct comparison.

 

[FonZ454]

I don't think we need to even debate the -05h wheel (clipped or unclipped). The debate if any, should be around the -06h wheel. But the compressor is what will really determine airflow which is the same in both turbos.

I gotta admit, I always wanted a 20g and may just pick one up just to see what it can do in a full weight 2g.

Isn't a Buschur 20g a clipped td05h wheel? I think all the fast cars were running BR 20g's.

 

[pickens]

Lets not get off track. We are talking about the flow capacity of the 20g (which is limited by the compressor wheel).