inh

Based on a 2.0 motor.. at about 17psi.
I have this feeling i should go with a bigger turbo, but the math plotted on the chart seems like a good choice..


the more i search, the more it looks like something like a gt3267r turbo is the way to go for about 20psi boost..


Modified by inh at 9:14 AM 9/28/2007

onefstek

get a gt30r you won't be dissapointed.

inh

Here is two differnt boost levels..

Grey is 25 psi, black is 20 psi.

On a well designed setup, this could make 500-600 whp, right?

thomas@LPS

the gt3071r will not make 500-600 whp. depending on the exhaust housing its limited to about 450whp. the other turbo you listed is going to support less than the gt3071r. probably only support 375whp.. i would suggest. either a gt30r like posted above or the gt35r. we have a fully built 2.0l gsr gt35r with a stock ported head and itr cams making 505whp (dyno dynamics) at 28lbs of boost. hope this helps you out...

inh

What trim is that gt35r you guys are using? can you post a dyno chart please?

Im finding that at about 30psi the pressure ratio is 3.. Most turbos dont run that through the sweet spot efficiency wise.. That, and to get any effeicincey out of it at all I have to move too much air, like >40 lbs/min.. a b20 needs to rev to like 9000 rpm to do that, and I dont think i can reliably rev that high.. but then again, maybe i can.. I dunno. I dont feel safe reving past that though..

at 29.4 psi, and a pressure ratio of 3, at 9k rpm, the lbs of air point on the map is 51. At 6500, which is about where the boost should start to build up and get towards that pressure ratio, im moving 37 lbs of air.. This is past the surge limit on the left on any of garretts gt35r turbos..

the gt30r below looks like it could work though. It gets kinda close to the surge line but not too close..





Modified by inh at 10:49 AM 9/28/2007

omiehomie

up for some info because i just got a hold of a 35r too and i would like to know the power levels of this turbo with a .63 a/r

inh

Found my turbo. Plotted below are three horepower levels, 400 (green), 500 (blue) , and 600 (red). THis is assuming the motor is a 2.0L, redlines at 9000, and peak boost pressure is hit at 7500 rpm.




Also, after taking a second look at gt35r compressor maps, it looks like i could run one of those too, but for higher boost pressures im closer to the surge limit.. It really all depends on how fast the boost pressure rises.. If its slower than I'd like, then i could get away with the 35, but if i want it to hit max pressure as fast as possible, then the 40 is the way to go, even if it spools slower..

0morgan@synapse motorsport

IMO those charts pretty much mean jack squat. there are too many variables that are unknown, pressure drop, IC efficiency, VE of your exact motor which changes through rpm's. not to mention i would think the exhaust housing would have a large effect on power production. why not actually look at setups running these turbos and see how much power they are making. 500whp is a cookie cutter setup no need to jump through hoops to figure out your turbo.

i listen to people a lot saying "im trying to size up a turbo for my specific motor, so im doing the calculations" after all the calcs it usually tells them to get a turbo thats like 3x too big for their setup.

inh

Well, I want as much power on pump gas as possible, which means i want to keep intake temps down.. which means i wanna jump through hoops to see which turbo operates the most efficiently..

Besides, its common knowledge that its better to make more power on a bigger turbo than a smaller one because of heat. A bigger turbo will produce less

mighty137

most BB turbos are pretty efficient!!! A nice ex manifold will also help too!

onefstek

I can tell you that from my own experience I would go with the 30r.

I had the 30r, 40r and now the 35r. And the 30r was the best for my set up and allowed me to run a 10.7 @ 134.7 in my full interior daily driver ek topping the scale at 2600 lbs.

I messed arrownd with the 40r and try to make good power and it did, it made 630whp and over 400 wtq, but it took too long to spool and I had to mid power, comparing with the 30r.

35r is the best for what I do now, but if your goal is only 500 whp then the 30r will be much better.

maxheat

Can you fit the GT30r on a b18c without shaving the block webbing? with a inlinepro log

inh

A very nice post! Thank you!

Originally, 500 whp was my goal, and i think now i want 500 with the option to go to 600.

Whats the specs on your 35r? Do you have a dyno chart?

onefstek

I made 575 whp with a well wornout 30r, im sure you can make 600 with a new one. Ill check to see if I can find my old dyno plots.

onefstek

Dyno charts

under_boost

500hp can be had with a 3076, or a 3082. if you want 500hp with an extra 100hp to grow, a 3082 would be your turbo.

nowtype

If the turbo won't flow 50lb/min, then you shouldn't look at it. Redneck math is 10lb/min = 100hp.

Compressor maps are valid. It just happens most people on this forum drag race and compressor efficiency isn't that important under said circumstances. mike@synapse motorsport opinion is simply invalid.

0morgan@synapse motorsport

my opinion is that they mean jack squat because you dont have the variable to put into the equations. how is that invalid? you honestly think that people are measuring the pressure drop across the intercooler or temp drops for efficiency. and they know the VE of their motor at that exact rpm?

nowtype

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike@synapse motorsport &raquo;</TD></TR><TR><TD CLASS="quote">my opinion is that they mean jack squat because you dont have the variable to put into the equations. how is that invalid? you honestly think that people are measuring the pressure drop across the intercooler or temp drops for efficiency. and they know the VE of their motor at that exact rpm?</TD></TR></TABLE>

You realize how little all of that plays into the equation? Also anyone with half a brain can assess those variables and come up with valid conclusions. If you want 500hp, you want a turbo that flows 50lb/min. You know this by looking at the compressor map. Also if you map out a compressor map well, you can figure out spool times and all sorts of other great things. I've done it. It can be done. It's not hard, as I'm not that smart and I've done it. Just takes a couple of active brain cells.

Hell, link me to any dyno sheet and a list of the setup and I can easily explain why the torque curve looks as it does.

inh

Wow.. lots of discussion here....

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by onefstek &raquo;</TD></TR><TR><TD CLASS="quote">Dyno charts </TD></TR></TABLE>

onefstek, i saw those charts before, and forgot to bookmark em.. Thanks for the link! It re-affirms that the GT40R makes power right where I thought it would. I do like the spool characteristics of the 30 better though.. I just wonder what intake temps are like? I see that the 30 was tuned on a mix of gas whereas the 40 was just pump.. I think i may use the 40R, and enjoy that extra cushion in case i ever end up with some bad gas.. That extra 50 hp just from 3 psi is a pretty good indicator of efficiency.. Looks to me like the 30R is getting stretched towards its limits up past 500HP..

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike@synapse motorsport &raquo;</TD></TR><TR><TD CLASS="quote">my opinion is that they mean jack squat because you dont have the variable to put into the equations. how is that invalid? you honestly think that people are measuring the pressure drop across the intercooler or temp drops for efficiency. and they know the VE of their motor at that exact rpm?</TD></TR></TABLE>

Volumetric efficiency is WELL documented, its not some black art... Everything else can be calculated, but will change daily (like intake temps and barometric pressure, etc) so while they do play a part in the calculations, its not a very big one. Turbo math isnt as complicated as it seems once you get to know it. If it was, and the charts are useless and theres no reason to go through the hassle, then why do turbo manufacturers make sure to have them available for all thier turbos?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nowtype &raquo;</TD></TR><TR><TD CLASS="quote">If the turbo won't flow 50lb/min, then you shouldn't look at it. Redneck math is 10lb/min = 100hp.

Compressor maps are valid. It just happens most people on this forum drag race and compressor efficiency isn't that important under said circumstances. mike@synapse motorsport opinion is simply invalid.</TD></TR></TABLE>

Very nice! 10lb/min isnt quite right, but its a good approximation =] I definitly agree with your statement about efficiency though. Yea, I COULD make 650 or 700 HP on a GT30R, but the intake temps would be insanely high, which is why cars that do this need water/methanol injection and/or high octane fuel. Im looking for big power on pump gas

to you guys for all the input

maxheat

sry.. i dont mean to jack but can you fit a gt30r on a inlinepro mani ac/ps without shaving the block webbing?

inh

to the top for more discussion

Schister66

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mike@Synapse Motorsports &raquo;</TD></TR><TR><TD CLASS="quote">my opinion is that they mean jack squat because you dont have the variable to put into the equations. how is that invalid? you honestly think that people are measuring the pressure drop across the intercooler or temp drops for efficiency. and they know the VE of their motor at that exact rpm?</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by inh &raquo;</TD></TR><TR><TD CLASS="quote">Volumetric efficiency is WELL documented, its not some black art... Everything else can be calculated, but will change daily (like intake temps and barometric pressure, etc) so while they do play a part in the calculations, its not a very big one. Turbo math isnt as complicated as it seems once you get to know it. If it was, and the charts are useless and theres no reason to go through the hassle, then why do turbo manufacturers make sure to have them available for all thier turbos?</TD></TR></TABLE>

my thoughts exactly....if compressor maps were useless, why would they be available?? People dont pick turbos completely at random. After working with turbo Hondas for a while, you may be able to say what would work for his setup, but if someone is looking for something completely tailored to his/her setup, reading a compressor map and matching it to his engine's needs is a GREAT first step

TheShodan

iTrader: (14)

Right, a good FIRST step.

Boner_Ben

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by maxheat &raquo;</TD></TR><TR><TD CLASS="quote">Can you fit the GT30r on a b18c without shaving the block webbing? with a inlinepro log</TD></TR></TABLE>
Yes, I have a 42r hanging off my inlinepro manifold with no cutting.