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Discussion Starter #1
May have been asked before,but is it likely that my GT3040 could be swapped with a GT35 easily?are the oil/water feeds the same and would it hook up to my existing old version or the Extreme Boost kit (i.e. downpipe etc etc?)
Thanks in advance guys!
Owen
 

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The Garrett site shows the GT35R to have a T3 inlet flanged turbine with a 4 bolt turbine outlet flange but no details for the GT3082R (GT3040). The HKS site shows the GT3040 to be have the smaller T25 turbine inlet flange but no outlet info. With few other details listed, I'm assuming it may be basically the same compressor housing because they both share the same 82mm compressor wheel, that's mated to the smaller turbine housing. I think ATS has used both in the past and might be able to add more. I believe Extreme sells both T25 and T3 adapters separately.

Why are you thinking of swapping turbos?

Bruce
 

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Depends on what turbine housing you are using.

The Garrett GT35R comes with a speciically designed turbine housing that features a 3" outlet with a 3.5" diameter 4-bolt pattern. It is considerably different then the standard Garrett 'GT 4 bolt' turbine housing.

However, most compaies have been using the standard GT 4 bolt housing on the GT35R because it allows a wider range of interchangeability between it and other turbochargers.

Most likey, if you are running a normal 'GT 4-bolt' turbine housing and can clear a T04S compressor cover, you'll be able to get a GT35R that will fit.
 

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Discussion Starter #5
Hey anthony,
the oil feed and block fitting turned up yesterday for the turbo so its back in the workshop in around a week i guess.I'll post more pics up as i get them.
The engine is back in and IC piping being made as we speak,going out to 3" instead of 2-2.5.
Bruce,
I was thinking of swapping turbo's as theres a lot of competition here in the UK now since i designed my build (almost 2years ago now!) so i feel i have to play 'catch up'.
Ideally i want a competetive 10sec car,i have the supporting mods (large TMIC,C02 Spray,272/264's,RMR center feed,720cc squirters etc) but i'm not sure the GT3040 will do it,what do you suppose?
 

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Our GT30 and 35 appear identical from the outside until you take a closer look @ the exhaust wheels. But our 3082 will not work with the EB kits I have seen. They would need a new DP. The flange diameter is bigger AND it is located farther away from the turbine wheel.
 

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elmo owen said:
Bruce,
I was thinking of swapping turbo's as theres a lot of competition here in the UK now since i designed my build (almost 2years ago now!) so i feel i have to play 'catch up'.
Ideally i want a competetive 10sec car,i have the supporting mods (large TMIC,C02 Spray,272/264's,RMR center feed,720cc squirters etc) but i'm not sure the GT3040 will do it,what do you suppose?
Owen, I look at the compressor and turbine maps to predict flow and power from spool to redline. While there are no maps for the GT3040, there are for the GT35R...and they look ideal to me for monster power. You and a few others have inspired me to post a related thread, hopefully tonight, that discusses this kind of stuff.

Bruce
 

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Thats a good goal (mine too, heh). Kindof off topic, but what bottom end are you using?
Also, you will need at least 850s to make the power required for a 10.99 (about 450 is what is required with perfect driving I believe. 850s are limited to about 500RWHP).
 

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Discussion Starter #9
hmm,so it'll be expensive to swap over.its all my own ?? though,i'm not even sponsored!I'm using 720's as they were easy to access at the time,i think i'll be going to 950's in the next few months.
I'm using a 2.0 bottom end with:
1 stock crank (althou knife edged and balanced)
2 Stock rods (shot peened,lightened and balanced)
3 Ross Forged pistons
4 spec stage x clutch (cant remember off hand,but easily power capable)
5 Toga HV pump
Does anyone think it will be possible to go to 10's with that turbo?(i'm hoping not to have to strip the interior)
I reckon the swap from a 3040 to a 35 will have a distinct detrimental effect on lag,although i wont be using it on the road too much,it'll be nice to have a bit of spool,hell i'm not gonna start like one of those "i want 600rwhp and stock spool time,what set up do i need" types though LOL)
or should i just have a 70-100 shot of D.P. ready? :0/
 

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Discussion Starter #10
Also,thank you so much Bruce for looking into this with me mate,i really appreciate it.
Man,i love this Forum :angel: :notworthy :notworthy :notworthy
 

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elmo owen said:
Also,thank you so much Bruce for looking into this with me mate,
Owen,

How much whp do you estimate will be required to reach your goals of 10's in the quarter? Have you seen engine's built to your specs and goals in the Racing Records section? I see engines with both turbos with pretty similar power results. It's hard to even tell which one spools quickest!

What we're going to need is an estimate of your airflow requirements because we not only need to see if they will plot on the GT35R compressor map, but to also use them in conjunction with the turbine's map. You could very well make less power by trying to use too high a flowing turbo for what your engine is capable of ingesting. The stock 2L 3S-GTE can only gulp so much air, which means it can only produce so much power no matter how big a turbo you strap onto it. After that you have to get really aggressive with the ignition tuning to give you the power. Now we have to figure out your airflow and from there there may be those who can better predict your peak power from that airflow.

Your engine with modified VE and redline will flow more but I have no idea how much. If you can give me an estimate as to how much it can flow at 4, 5, 6, 7, 8k, 9(k) rpm at your desired boost level, then I can tell you at what rpm it should be able to hit that boost level. Also, over what rpm range will you require the insane power...6-9000? 6500-8500?

Bruce

Edit: I see Po's estimate of 450 whp...is that about right?
 

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Discussion Starter #12
Cheers Bruce.
Right i'm guessing with research i'll need around 500rwhp to even mildly entertain a late 10.
keeping in mind its just a goal,i'd like to obtain it.I have noticed MR2Liter has built a much wilder set-up (and a fantastic looking one i might add!) he still notes in his recent post about it not being a sole track car,but used to have fun on the street mainly.. this in mind i gather that i should be able to run this size turbo on the street with no probs.
I'll doo a search for the GT3040 compressor maps,i dont know if there are many around.
The engine will tolerate a high redline due to the weight of the internals and HV pump being in place i would have thought.My VE has been altered using cams only (i think) no porting or polishing has been carried out,it still uses stock valves too,but engle springs.
How do i work out how much air the engine can flow at determined increments of 1krpm?
to run the 10sec i'm aiming to run approx 30 PSI but only for the run,i'd like to use pump gas,but over here that 99ron Oct. so i dont know how that equates to the U.S. equivelant.On the street i only plan to use maybe 20-24psi Max to try and retain some reliability and longevity of the engine (using a 60-70% capability) although i'm guessing a turbo of this size will only work better and better the higher up the rev range it goes.
I also know the (well,i say "know" i asked J from E.B. the spec on the turbo and i was told so..) turbo has a .6 A/R and a 56trim on it (from what i understand,this was standard for the early EB kits)
Maybe it will,maybe not but if i can squeeze that E.T. out of it at a push,the daily driving shouldn't be all too bad.
P.S. sorry for the novel.. :0)
 

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Discussion Starter #13
Also Just noticed,ATS made 554hp from the very same kit and a similar spec to mine at 27PSI.......
 

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Check out the calculations at hhttp://www.lovehorsepower.com/MR2_Docs/compressor_flow_maps.htm. Then go to the the table of calculations at the bottom of that page to see what airflow is achieved at different rpm...use the table for lbs/min that you'll see on Garretts compressor maps. Note that they used a volumetic efficiency of 90%, but you may be closer to the competition engine 105% that he mentions because of your cams, etc. If so then you need to get out the calculator for yourself and figure out the flows to see what hp is available from the airflow alone. If you aren't going to run high octane race fuel than you may not be able to get extra power from advanced ignition timing. Check that out as a start to see the factors involved.

There's a general rule of thumb that I've seen used that says you get approx. 10 hp per lb/min of airflow, and more is possible if you're running race gas, then deduct 20% for driveline losses. That tells me that you'll need to flow over 60 lbs/min to net 500 whp on pump...and I just don't see that being possible. You will be airflow limited and need to make the extra power with race gas and a brilliant tune. You'll notice the guys on the dyno registry in the racing records section have used varying amounts of boost, plus race gas, plus every conceivable VE mod in the book.

If I'm wrong I hope someone will correct me. My experience is on stock set-ups but the basic rules of more air (and appropriate amounts of fuel) for more power don't change. Time to crunch some numbers and then see if they can be plotted on a compressor map! I'd use the GT3582R map on the Garrett site if you can't find one for the Gt3040R since they both share the 82mm compressor. Let us know if you need anything to do that.

Bruce
 

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The GT30 turbine is better matched to the 76mm GT30R compressor wheel. It is too small in diameter for the 82mm compressor wheel. It also can not keep up with the flow potential of the 82mm compressor wheel.

At any given boost level, the GT3582R makes more power and almost identical boost response to the GT3082 in the few comparisions I have seen.

With the Garrett GT35R (3" outlet), there are a couple Hondas making over 630 WHP. I think one even topping 670 WHP. The GT3582R is one bad ass turbo.
 

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99_GS-T said:
At any given boost level, the GT3582R makes more power and almost identical boost response to the GT3082 in the few comparisions I have seen.
The GT3582R should actually boost sooner because I can't see how the GT3082R could possibly have as high a turbine efficiency rating with the widely spaced 82 and 60 mm wheel mating. When I check dynos of each they seem about the same however. This is the problem when you can't see compressor and turbine maps...you end up guessing at stuff you should know for certain, and the nature of the cars being dyno'd makes it difficult to tell what the turbo is doing.

Bruce
 

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Bruce, from what I have seen, the GT35R comes in about 100-200 RPM later then the GT3040. To me, that's not even going to be noticable on the street.

The GT30 is a lighter turbine and will get to a higher pressure ratio (energy level) quicker then the GT35R. I would assume this would help get it up to boost quicker.
 

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99_GS-T said:
Bruce, from what I have seen, the GT35R comes in about 100-200 RPM later then the GT3040. To me, that's not even going to be noticable on the street.

The GT30 is a lighter turbine and will get to a higher pressure ratio (energy level) quicker then the GT35R. I would assume this would help get it up to boost quicker.
You know what they say about "assume" :)

I analyzed graphs for an hour one day. Couldn't find two set-ups close enough for a decent comparison...but I thought it looked like the GT35R spooled a bit earlier. To protect privacy, e-mail me what you were looking at and we can thrash it out in private.

Now where did this theory about higher pressure ratio and quicker spool from a lighter turbine come from? If you're thinking it's lighter because it's smaller, and the reduced inertia would help it spool quicker, then I'd suggest that it's poor wheel ratio would decrease it's turbine efficiency more than the improved inertia would help it...and the net result would be slower spool, and a top end that would eventually become restricted.

Bruce
 

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99_GS-T said:
Bruce, from what I have seen, the GT35R comes in about 100-200 RPM later then the GT3040. To me, that's not even going to be noticable on the street.

The GT30 is a lighter turbine and will get to a higher pressure ratio (energy level) quicker then the GT35R. I would assume this would help get it up to boost quicker.
Double posted...my bad
 
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