danp1uk

Is this too big on b18c? i have a pfab top mount mani with 3 1/2" downpipe, ive already brought the turbo so i really hope its not... i completely undrstand that it is going to be very lagy but is it going to be too lagy to drive?
Im also running a victor x inlet, full brian crower valve train with custom made to my engine builders spec cams.
Can anybody have a rough guess at what RPM im likely to hit boost? also being a 1.06 housing will it make more power than say a .82?

Schister66

Can you give us more details about the setup? Its hard to judge spool and 'whether it will be too laggy to drive' when we have very minimal info to work with.

-Engine specs
-Power goal
-Use for the car

Those would be a good place to start

danp1uk

35R 1.06
spfab top mount mani with 38mm tial W/G
3 1/2" DP
darton steel liners
81mm cp 8:5:1 pistons
eagle rods
full crower valvetrain with custom cams
s300
victor x
1000cc ID's
S9B box with lsd
intank walbro with bosch 044 inline

Im aiming for around 500bhp

minimal street use, maybe once a week, will be visiting the 1/4 mile often and will probably do about 4 track days a year.

TheShodan

iTrader: (14)

that's quite a large housing to use for that purpose. If "lag" is a concern, you would be going the wrong direction with this turbocharger

iamthefollower

I would see some boost lag with the compression that low and the exhaust housing that size, I had a 1.00 a/r exhaust housing on my LS/Vtec but my compression is about 9.8:1 and it was seeing full boost at 3/4 throttle around 3800rpms but yours is going to be a little more most likely with your set up.

turbohatch96y7

iTrader: (15)

i have a 1,15 ar and my turbo starts spooling around 5300rpm so yeah it will take a while but mine is a stock gsr with gsr cams its not too bad

sjp00422

iTrader: (2)

Ooh! Very interesting..wonder how this would do on a built gsr with 9.8:1...Shodan?

LS AzZkIkr

If your going to mostly drag the car then lag is NO issue unless you cannot even spool the turbo. You will never be lower than 6k rpm if your trans/tire setup is correct. I thought I had a big turbo for a street car and now I want a bigger one mostly because I will be driving mine about the same as you described. I say go for it and show us the results.

TheShodan

iTrader: (14)

There is still no benefit running that large of a volute for a mid-framed turbo such as a GT35R on a Sub-3 litre car. Even a Honda. Look at the purpose again. I feel that even with 9.8:1 compression, you will not be satisfied. Ball-bearing or not.

I disagree, too big for the purpose.

sjp00422

iTrader: (2)

I see I see..dude i cannot WAIT til I can finally start piecing my turbo together

92TypeR

Are you talking about the ATP 1.06 divided T3 (or T4) or the garrett open 1.06??

If the 1.06 is divided, and you have a proper divided manifold and WG setup, you will decrease spool, increase response, and increase peak HP when compared to the standard open 0.82 T3.

30psi_gst

Its said that higher compression doesnt spool a turbo up any different then a lower compression motor. Its the tq that makes it feel like its moving faster. If there is a difference there, its not noticeable. I dont have any proof of this so i cant really give any examples. All i know is that my DSM is 7.8:1 stock and now it is 8.5:1 and theres no difference in spool at all, and it was logged thru a map sensor.

The OPs post. If you can stand the lag, go for it. Hell, should make a lot of power on pretty much no boost. Id try to find another housing tho.

TheShodan

iTrader: (14)

A divided 1.06 will not decease "spool" as much as you would think on a sub 3 litre engine. this is not a "twin scroll".. see sig

92TypeR

2.0L B, 3076R, Garrett T3 .82 divided (twin tial mvs, divided merge collector) - peak torque @ 4700rpm.

Same engine setup, switched to ATP 1.06 T4 divided with new T4 divided merge collector - peak torque @ 4100rpm, peak HP increased by 35.

These results mirror what Geoff has been seeing for a few years now.

PS - I never mentioned twin scroll.

I don't think the OP is looking specifically at the ATP 1.06 divided housings, but he would have good reason to.

TheShodan

iTrader: (14)

that's fine. Peak torque was at 4100rpms for the one gear. You gotta remember what the DYNO represents; one gear, optimal conditions, as a snap shot. I'm not saying it doesn't happen, what I'm referring to is the recovery reaction of the exhaust energy in between gears as those exhaust gases take a bit longer (from more volume, not velocity) to exit the volute of the larger turbine housing. That could easily affect his acceleration rate. The increase in horsepower is to be expected because of the larger volume, so there's no surprise there. Hopefully, that increase is in the right part of the powerband so that a person can make up for the acceleration loss in the lower rpm band.

Now if the purpose is drag racing, there are other ways to counter act the effects of that more-than-likely loss of acceleration. But for most time attack circuit and street cars, that smaller housing (given that the turbine wheel is the same) is going to help with the individual in their recovery response IN BETWEEN shifts more than just the change in one gear. You must look beyond that dyno snap shot when it comes to picking out any of that equipment, ultimately.

spectacle

More people should listen to you Shodan. For real

Only took 6 yrs but 1k post! lol

riceball777

i beg to differ. I have real expearence with my evo. I now have a t4 divided 1.06ar gt3582r on my evo with the full race twinscroll manifold on my evo and i hit 20psi by 4k rpm in 3rd gear with the stock 2.0 motor. This set up spools faster than my old single scroll gt3076r did with the .63ar hot side and it makes way more power up top. Twin scroll will make way more mid range and way more usable power and will spool way way faster. After running a proper divided manifold and turbo i do not ever recomend to run a single scroll/ open scroll setups unless you want to keep cost down.

1.06ar open scroll will be laggy like **** on a b series.


pics of my twin scroll t4 1.06ar gt35r set up

ahobbs

^^^^good stuff. I have been debating this in my head now for quite sometime. Thanks for the info.

LS AzZkIkr

Would switching from a divided t3 84a/r to a divided t4 1.00 a/r increase lag without having a divided manifold? I thought that it may move up where a motor makes its power?

danp1uk

I understand what you are saying, i think im going to just go for it and hope for the best, if it is far too lagy for my liking then i will change to the .82 housing, on my last setup i was hitting full boost at 6k on a cheap and nasty ebay t3/t4, shodan do you think i will be hitting full boost at 6k? The car will be rev'd to about 9500k so there should be a decent powerband between the 2.

danp1uk

couple of pics of the manifold and turbo. Manifold is 1.06 open scroll

TheShodan

iTrader: (14)

That's fine. Differing opinions are good... I have "real" experience as well with both platforms. You do realize that having an ACTUAL twin scroll (vs. divided) on an EVO 9 is completely different with regard to exhaust pulses than a Divided housing on Honda, correct? What is the purpose of the car?

It just seems over the years I've raced both cars i've been able to gather that for every twin scroll larger turbocharger that an Evolution 9 uses with its larger housings, a Honda B-series can catch and respond just as fast if not faster in recovery from 4300rpms to 8300rpms on most circuits going from 3-5th gear, and surprisingly do it with less boost pressure in a smaller housing overall. From Willow run to Mid Ohio, it just seems that Evolutions 7-9 [god bless them ;-) ] just seem to have to use more boost pressure and try and dissipate more heat than the similar investment in the honda turbocharger systems. And I'm far from being the best driver around, trust me.

I love them both. But this is seriously apples to oranges comparison from the 2 engine platforms and usability. From cylinder head design, to engine demand flow characteristics, they are just too different. Where the 4G63 and 4B11 can handle more backpressure from the increased heat, the honda B-series, (and especially the K-series) engines have been able to do more, with less. They are just more sensitive to backpressure than the Mitsubishi, Mazda, and Subaru.

Hell, I had more fun and was able to make more midrange in Pete's old Evolution 6 with an HKS GT3037S Pro and his T04Z in the open .82A/Rs than with the divided housing stuff. In the end, its all in what you use the car for from my experience.

danp1uk

shodan?

TheShodan

iTrader: (14)

with a top mount manifold, with that low of a compression, I could see 6K as maximum pressure under 20 psi. It will come on like a light switch, but it really depends upon what your trying to use the car for. This is definitely a drag-race based setup. Like you said, try it and find out. Only you can be the one to determine if it's too "laggy" or not in the end.

danp1uk

cheers shodan, thats what i wanted to here. i will just have to try it and hope for the best. Is my compression too low then? I was under the impression that the lower the C/R the safer it is for boosting?