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Hey guys, could use some advice.
Im running a 6port with 9.4 compression rotors.
I was getting 180rwhp out of it NA, looking to try something different.
Im not looking for max power, Im looking for transient throttle response you would want in an autox car. Im ok with power falling off a little on the top end. Im aiming to make at least 225rwhp, I dont imagine I need a crazy high amount of boost, Im thinking 10-14psi
gtx3076r with 1.01/ar or gtx3575r .83ar should get me what Im looking for but I dont have enough experience for the finer details to know which would be the better choice.
Ill be fabbing up my own manifolds and stuff so t3 vs t4 flange doesn't matter much to me.
Im hoping to go with an internal wastegate, I dont think that low boost level merits an external one.
No need to get too over the top with those modest goals, for the sake of being different. I mean, if you want to fab a manifold that's fine and dandy, but just know that there is no need to 'reinvent the wheel'
:3
K.I.S.S (keep it simple! lol) https://www.rx7club.com/time-slips-d...-turbo-701849/
There are LOTS of ways to get to your goal without spending that kind of $$ on a turbo which you will want to upgrade eventually AGAIN, heh...
Not to rain on your parade or anything, or to be a dick. Just tryna help you see the whole picture and how much easier it can be The 'standard' covers virtually all of your bases for the most part as well, so, yeh.
Besides, just going from N/A to turbo is a task in its self, there are and is LOTS of writeups/info I'm sure you're aware, and of the documentation this 'swap' has gotten over the years. I agree it's nice to be different, but a 6 port is still different hell you could still do your own manifold and everything if you wanted (well, you intake will need modification anyways so there's that, or start from scratch).
Its doubtful the stock manifold/turbo combo will fit or give me the response Im looking for.
Ive had an s5 turbo many many years ago with an upgraded compressor. It was fine for drag racing and street fun when taking off in 1st gear. Im an old man now and do do that stuff much, however digging out of a turn on 2nd gear at 2500 rpms it was not acceptable for what I want. I want to build boost faster than the stock turbo, hit peek power early, say 6000 rpms and have some falloff to redline.
I was even thinking after posting last night a step down on the exhaust side, say .63 on the gtx3576 may even be a better match for my goals though I may need to go external wastegate to control backpressure/boost at higher rpms in that scenario though.
Its doubtful the stock manifold/turbo combo will fit or give me the response Im looking for.
Ive had an s5 turbo many many years ago with an upgraded compressor. It was fine for drag racing and street fun when taking off in 1st gear. Im an old man now and do do that stuff much, however digging out of a turn on 2nd gear at 2500 rpms it was not acceptable for what I want. I want to build boost faster than the stock turbo, hit peek power early, say 6000 rpms and have some falloff to redline.
I was even thinking after posting last night a step down on the exhaust side, say .63 on the gtx3576 may even be a better match for my goals though I may need to go external wastegate to control backpressure/boost at higher rpms in that scenario though.
get a stock one, or get the smallest EFR turbo i would put on a rotary a 6258. should max out at 330hp. also you will have better then 300ftlbs of torque by 3k rpm. prolly 250 at 2000.
stock you could walk away spending less then 1000 swapping what you need.
the efr is 1600 for just the turbo.
there are many options between.
Last edited by lastphaseofthis; 02-22-17 at 11:38 AM.
If you are trying to do this cheap, the primary turbo from the FD twins can *just* do 250rwhp.
There was a blown set of '99 spec with 1 good turbo for sale on this forum that would be a good source.
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If you have some $ to spend,
I think EFR 7163 would be the best because of the compressors superior surge line.
You have to go down like 3 EFR turbo sizes to get back to the same low boost surge line as the EFR 7163 (7064, 6758, 6258).
Well, 6258 can do 290rwhp on rotary- but I think EFR 7163 will work better because the higher flowing exhaust wheel will raise the engine VE and also allow you to carry the torque further toward redline for more torque at the wheels through gearing.
I bought a couple 7163 for $650 used at the end of last Indy race season.
Judging from how hair trigger my EFR 7670 in T4 1.05AR was I think the EFR 7163 in T25 0.85AR is going to be a twitchy ride!
I saw there is an EFR 6758 IWG T25 0.85AR on Ebay for $1,000 (used IRL 6758 with new exhaust housing) if you need something right now.
Im hoping to go with an internal wastegate, I dont think that low boost level merits an external one.
Ok, bear with me- I have some experience on this.
For best turbo response you will want an intake with velocity stack and the biggest diesel truck filter you can find (I used 6" base 12" long one) and as big exhaust as you can fit/run (I used 3.5" one that has big gains in spool over 3" one I had before).
These intake and exhaust mods can make as much difference as choosing your turbo size.
However, with these mods it will be a challenge for IWG to keep the boost down.
You can do it though- especially since you want low power output. I would do it by putting an exhaust restriction as far back in the exhaust as possible. Don't be surprised if you end up with a 1" outlet at the exhaust tip.
If you do big external wastegates it will help the engine make more power and be more reliable through improved VE.
You can experiment with this on your own. If you get a turbo where the compressor maxes at the power you want to make you can experiment on the dyno with holding the wastegates shut the whole pull or letting them open.
Huge gains on the top end from opening the wastegates and it will hold peak boost longer (because the engine is making more power and hence more exhaust to keep the compressor rpm up).
Blue boost trace line is my EFR 7670 with wastegates held shut (aborted run).
Other lines are with dual 44mm wastegates opening.
Not really looking for the cheapest route.
Peak power output isnt the goal, and 225rwhp is just a minimum I expect.
If I can make 300rwhp (i know its not happening with what I have) and I can have power and torque curves like the thread linked below Ill be pretty happy. If I peak at 225 and have similar curves, Ill still be ok with that.
I was looking at borgwarner turbos a bit last night and today. Not familiar with them at all, but the 6780 and 7163 look like they would fit my application assuming I filled out the match bot correctly
The lower gauge on the "Mickey Mouse ears" Greddy gauges is boost. Straight up at 12-O-clock is 14.7psi and over at 2:30-O-clock where it peaks is 26psi.
You can see the response is pretty good even on this larger EFR turbo.
Damn, that is quite appealing... That torque really pours on... Maybe I need to give the 7670 a little more thought over that damn 8374, heh. Interested to see how a 7163 performs/what the curves are like there....
Cheers, look forward to the result mikey, keep us posted.
Yes . Expect more muffler system backpressure than 2psi (unless you have a full 3.5" free flow system) and follow the matchbot recommendations for how backpressure on filter/muffler and IC are affected by flow at lower rpms.
It's been about 10 years since I was doing turbo stuff, lol, I'm pretty out of date
I think I have a time slip in the time slips section were I pulled a low 12 with a Stockport s5 13b and a carb/turbo.
Total pos.
Blue TII Thanks for the info. Exactly what I was looking for.
i think you've made up your mind, but my car ended up as a mini me to Blue TII's car, its quite a lot of fun.
its basically just a stock turbo + boost control. back of the envelope says its about 210hp@5000rpm, but its doing stock boost (7psi) by 2400rpm, and 13psi by 3200rpm, its quite fast in the 2500-4500range, really fun too, because thats where you're driving most of the time.
transients suck, but its got a cat, AFM, and S4 turbo, plus the biggest intercooler that will fit the car. i think a bigger compressor on an S5 turbo would actually help response.
I had a 330rwhp s4 highflowed turbo with a 57mm compressor (to4e?) response was excellent - was instaboost anywhere above 3000-3500. It think trying to split the atom getting full boost at 2000rpm is a bit like pissing in the wind and in most cases not worth it. Just drop down a gear and enjoy. It is a rotary after all.
It's not about hitting full boost at a particular rpm Or how much power can be put out, It's about usable powerband and transient throttle response. Look a blue's dyno numbers and video,. It's a very nice setup and is doing something similar to what I want.
A stock turbo will never achieve that kind of response.
Actually,
I had a Stock Hybrid before on the same set-up and it did have similar response, but there was just no way to control the boost creep even with a 60mm external wastegate on it.
The stock hybrid actually had a little better response off idle- it would leave black stripes if you let out the clutch to fast like a V8.
The little T25/T3 sized stock turbo manifold/exhaust housing runners were just too small/high velocity.
So, went from 58mm minor diameter O trim exhaust wheel to the larger 64mm minor diameter P trim exhaust wheel and cut the exhaust housing scroll slots twice as wide (divergent AR) and finally had to port the manifold and exhaust housing runners big (T4 size) up to the wastegate favoring wastegate flow.
All in stages until boost creep subsided- and when it was all done the response was soggier.
The rest of the set-up (engine, intake, exhaust, etc) is going to have more impact on the response than whatever turbo you put on it in my experience.
02-21-17, 09:18 PM
The 'standard' covers virtually all of your bases for the most part as well, so, yeh.
