Which Turbo For Vq25-Det?

[bechopps]

hello all,

i go by the name chopps.

I have a 2001 m35 rs4 and want to upgrade the turbo. i am aware that i have the option of high flowing the existing turbo. And what is involved to get it done, with a rough idea of performance gains. I have been asking around about options and been told that a garret t28-64 can be fitted with performance results comparable to high flowing the original.

I want to know what people have fitted to the VQ25-det and with what results? What are peoples ideas and experiences? Does any one have a better option than the ones i already know about? Who has fitted any other turbo and what is their honest opinion's?

I would be grateful for help so let me know what you know! Cheers

[scotty nm35]

I think you have been mis-informed, no-one here has fitted anything other than a highflow as far as I know. I am about to start work on a manifold adapter to run a GTX30 but it is a month off yet. Why don't you like the highflow? It would be a cheaper option as nothing else will bolt up. A t28 isn't the answer, our stock housings flow better than those, even better than the r34's op7.

What sort of power are you looking for and who is doing the tuning?

[andy65b]

I highflowed the stock turbo to a Sierra Stage 1 kit and that netted a gain of approx 14% over the stock turbo..

[Jetwreck]

hello all,

i go by the name chopps.

I have a 2001 m35 rs4 and want to upgrade the turbo. i am aware that i have the option of high flowing the existing turbo. And what is involved to get it done, with a rough idea of performance gains. I have been asking around about options and been told that a garret t28-64 can be fitted with performance results comparable to high flowing the original.

I want to know what people have fitted to the VQ25-det and with what results? What are peoples ideas and experiences? Does any one have a better option than the ones i already know about? Who has fitted any other turbo and what is their honest opinion's?

I would be grateful for help so let me know what you know! Cheers

Who told you the t28 would be better? I would be quizzing them a little more.....as you will find out there are a lot a workshops that think they know but don't. Does he know that all new headers will have to be made?....and it's a motor our job?....and when you get it back in without the rest of the parts you may be making only about 5-10KW's more?

How much power do you want?

I have h/f'd our standard housing's with a GT30/71r core and Garret BB set and hit 270AKWK's on BP98 at 15 PSI and only stopped because the gearbox was not handling it....we are pretty sure the standard housings will be good for 300AWKW's.....f#$k knows what it would do on e85 but I would be thinking around the 340-350AWKW mark. This setup has taken a long time to sort and without all the other custom made parts it ran like a pig.

[Sunkist]

and i went with a stage 2 sirerra comp wheels with a journal core highflowed into the standard housings.

and got 285kw atw(with supporting mods) on pump ..but a little laggy. (its fuel tuned for e85 for safety)

look at the graph

judging by the response of the stock turbo that scotty dynoed up(225kw)

I'de say a tuned stage one sierra would be perfect for an everyday use.

or if your chasing just numbers. wait for scott to finish what he's doing first!

[Jetwreck]

and i went with a stage 2 sirerra comp wheels with a journal core highflowed into the standard housings.

and got 285kw atw(with supporting mods) on pump ..but a little laggy. (its fuel tuned for e85 for safety)

look at the graph

judging by the response of the stock turbo that scotty dynoed up(225kw)

I'de say a tuned stage one sierra would be perfect for an everyday use.

or if your chasing just numbers. wait for scott to finish what he's doing first!

I'd have to disagree with you on that Aaron.....nothing wrong with the way mine drives at 15psi ...shit it's even good at 10PSI now with the preload...I pickup and go at about 3,000RPM(enough to break traction).....yours still needs sorting out as not everyone wants to run 22 PSI all the time with nothing down low( I know your pain)....get an EBC on it and it will fix a lot of your low down problems. e.g where you producing 60AWKW's I was producing 135AWKW's....f#$k knows what mine is now with the preload!

and i'm getting 14-15lt's per hundred on city cycle and 10lt's on trips...not saying the sierra S1 is not good either!

I have attached my dyno sheet but it's a little different now with when the power comes on....that 100KM/h's mark would be more like 170AWKW's now.

Edited March 24, 2011 by Jetwreck

[Tommy Kaira RL]

I have just done a gcg high flow. It was an engine out job. I got a 28/71 core. The power is increased a little and it is alot smoother. If your going to do the job I know a good place. Once the turbo was out I got the turbo rebuilt by ATS ask for Bill. He has done a few M35 turbos now.

[Sunkist]

I'd have to disagree with you on that Aaron.....nothing wrong with the way mine drives at 15psi ...shit it's even good at 10PSI now with the preload...I pickup and go at about 3,000RPM(enough to break traction).....yours still needs sorting out as not everyone wants to run 22 PSI all the time with nothing down low( I know your pain)....get an EBC on it and it will fix a lot of your low down problems. e.g where you producing 60AWKW's I was producing 135AWKW's....f#$k knows what mine is now with the preload!

and i'm getting 14-15lt's per hundred on city cycle and 10lt's on trips...not saying the sierra S1 is not good either!

I have attached my dyno sheet but it's a little different now with when the power comes on....that 100KM/h's mark would be more like 170AWKW's now.

its at 20 psi lol not 22.. Cihan was able to bring it down.

i reckon that 20 PSI is where the extra 15kw is. maybe ide be the same as you on 15-16psi which i would no doubt love. and yeh a EBC would fix it perfectly for me with gain. i reckon my midrange will sky rocket as I would be on 20psi by about 3,500rpm. rather than 16psi from 3k-4500rpm and 20 psi from 4500 to limit. wastegates a wee bit to small.

at the same time i like that it does that though. it feels like ive hit a nos button at 4500rpm lol

I already have no traction at all in first - second lets go at about 4500rpm (gotta love shitty tires )

so im not doubting the drivability but some people prefer to get on it as soon as possible and arent too worried about top end - as craig would be the only one to reach it on a street lol

oh and craig - that torque line is awesome. held throughout the rev range!

[ironpaw]

What exactly is "preload", and how can an EBC help?

I'm sitting at 17 psi and boost comes on at around 3k rpm....

[Sunkist]

pre load means the spring for the actuator has load while its closed. it doesnt allow flow throught the wastegate until at desired boost. (the backyard spring jobby)

EBC adjust's and can delay the signal to the actuator allowing you to boost up much quicker - but to much delay causes spike

[ironpaw]

ahh ok...

So this is the actuator mod that scott's talking about

Must try it...hmmm

[Sunkist]

yeh.

it creates a pre load so your mid range is improved.

i think scotts doing them as swap jobs.

[Jetwreck]

What exactly is "preload", and how can an EBC help?

I'm sitting at 17 psi and boost comes on at around 3k rpm....

Preload.....bigger spring on the actuator so it the wastegate stay's closed longer....our standard 7PSI internal spring is shit.

EBC you can control the gain a bleed off to hold the desired boost.

I have driven your setup in another car(a white one) Your does launch....it's a baby .......in all seriousness mine only used to come on after 5,000RPM at 18PSI when I first put it on and I don't think it had much more power than standard....It was damb right dangerous when crossing intersections.

Let's put it this way....if you were to race Aaron over the quarter you would win....he might start to pull you in at the end but 5 car length's of momentum is way to much to make up....and I'm talking with your BP98 fuel map.

Aaron if you can get a decent EBC on your car you will find it improves! but the only real way to get it going is to remove the throttle restriction and fix the waste gate.....there is no reason your car cannot have good positive boost by 3,500rpm's at least.

[Sunkist]

Preload.....bigger spring on the actuator so it the wastegate stay's closed longer....our standard 7PSI internal spring is shit.

EBC you can control the gain a bleed off to hold the desired boost.

I have driven your setup in another car(a white one) Your does launch....it's a baby .......in all seriousness mine only used to come on after 5,000RPM at 18PSI when I first put it on and I don't think it had much more power than standard....It was damb right dangerous when crossing intersections.

Let's put it this way....if you were to race Aaron over the quarter you would win....he might start to pull you in at the end but 5 car length's of momentum is way to much to make up....and I'm talking with your BP98 fuel map.

Aaron if you can get a decent EBC on your car you will find it improves! but the only real way to get it going is to remove the throttle restriction and fix the waste gate.....there is no reason your car cannot have good positive boost by 3,500rpm's at least.

gee thanks craig!

and yeh i will eventually fix the wastegate and get an EBC to be honest i just CBF doing it right now. its tuned at 20 psi so its safe. im gonna wait till i get over having this power(which i sort of am) coz then i improve things and i become happy with the car again.

and it does have good positive boost by 3000rpm, by then im at 15 psi. the fact i dont have a boost controller and that its running directly off the actuator+spring.

i want an ebc and open up the WG hole so i can actually push this turbo and see what the car actually does.

remember the cars only "fuel tuned" on e85 not power tuned. i havnt taken advantage of e85 yet. just the safety

[ironpaw]

When does Aaron's come on? 4k?

[Sunkist]

im at 15-16 psi by 3k RPM.

because my wastegate port is too small as the revs reach about 4500rpm the wastegate port cannot flow anymore air so it goes through the turbine fan and continues boosting to 20psi and holds it till rev limit.

i can get an EBC and be on 20psi by 3300-3500rpm.

but I CBF right now.

i dont understand whats confusing about it? lol

[ironpaw]

Hmm I think its because I have no idea when I come on boost or when hit peak boost...really need to get an EBC I guess!

[Sunkist]

install your emanage software to a laptop and log it.

it will tell you when your at 16psi by

or just watch it in 3rd gear and guestimate!

[Jetwreck]

im at 15-16 psi by 3k RPM.

because my wastegate port is too small as the revs reach about 4500rpm the wastegate port cannot flow anymore air so it goes through the turbine fan and continues boosting to 20psi and holds it till rev limit.

i can get an EBC and be on 20psi by 3300-3500rpm.

but I CBF right now.

i dont understand whats confusing about it? lol

I'm not bagging you Aaron.....I'm simply saying that once sorted you car will be much better than were it is atm...and it's not that far away from being completely sorted on the motor side of things(you would have to agree)...you will see and then go....ahhh I now know what that dickhead was talking about!!!!....your's is more of a dyno queen atm! Do you really think that it is faster than Scott's old setup? Do you think it would even smash his current setup? If is has then I am mistaken as I am only going off what the Dyno sheet is telling me!

I should I know....I've been driving around in a POS for the past 2 years while we sorted parts....went I first put my turbo on there was no locally produce parts period so I have done this step by step part by part as has Scott!......even after the tune I did in Jan I thought that the figures and tune was great but it's still does not feel like a car that is producing 270AWKW's....it was still not nice to drive due to low end lag!...didn't help that my EBC shit itself about 2 weeks after either.......it's really only since I put the Pre-Load on that I can say it's a fast car everywhere I stomp it...and I know it produces power right up into 5th gear.

Like I said mate not having a go.......I'm really only saying there is no reason that your car will not perform as good if not better as a sierra stage 1 with a couple more tweeks.....and I'm not talking about how much power it delivers at 6,500RPM at 20PSI either.....I'm talking about the other 3,500 RPM before that.

Edited March 25, 2011 by Jetwreck

[Sunkist]

I'm not bagging you Aaron.....I'm simply saying that once sorted you car will be much better than were it is atm...and it's not that far away from being completely sorted on the motor side of things(you would have to agree)...you will see and then go....ahhh I now know what his dickhead was talking about!!!!....your's is more of a dyno queen atm! Do you really think that it is faster than Scott's old setup? Do you think it would even smash his current setup? If is has then I am mistaken as I am only going off what the Dyno sheet is telling me!

I should I know....I've been driving around in a POS for the past 2 years while we sorted parts....went I first put my turbo on there was no locally produce parts period so I have done this step by step part by part as has Scott!......even after the tune I did in Jan I thought that the figures and tune was great but it's still does not feel like a car that is producing 270AWKW's....it was still not nice to drive due to low end lag!...didn't help that my EBC shit itself about 2 weeks after either.......it's really only since I put the Pre-Load on that I can say it's a fast car everywhere I stomp it...and I know it produces power right up into 5th gear.

Like I said mate not having a go.......I'm really only saying there is no reason that your car will not perform as good if not better as a sierra stage 1 with a couple more tweeks.....and I'm not talking about how much power it delivers at 6,500RPM at 20PSI either.....I'm talking about the other 3,500 RPM before that.

yeh i know it will be much better in mid range if i had it running at 20psi by 3300rpm.

im not saying that my current set up would munch scotts old setup. but the results in jethro's car as to when they were in scotts car are pretty different - maybe because the dyno has been re calibrated - but scott was making over 1100nm. where as(correct me if im wrong jethro) Jethros making about 750-800nm. i guess the next time your in melb i have to take you for a spin.

an EBC should give me about 130kw - 150kw at about 3300rpm which will be a big difference. in mid range. which i know will be fixed with the 2 small mods(EBC and WG open) and would probably give me a few more KW topend as it will flow better with the WG opening up(when performance tuned)...but like i said i CBF right now. lol i'll do it when im over it. the reason why you got over it so quick is coz of the GIO 32 and the 31 you used to have.

call me a noob but this is the first car ive had at that power - i still havnt even "floored" it as im just to scared - hoenestly...

i mean im already making enough power to spin up all four in first, and wet in second lol its enough for now. the Problem isnt really a problem until i get over it.