Fun street RB25

[Rand0b]

On 5/20/2022 at 9:51 AM, Kinkstaah said:

Borg Warner EFR's are the best at that. It is their entire thing. No turbo comes on that slowly (under full throttle) but you could set a boost controller to do that if you wanted to.

Boost by gear and artificial traction control by tapering boost on slowly is a thing that people do, but then you have a scenario where you either make the boost come on slow enough to keep grip in 4th (and thus 1-2-3 is wheelspin still) or you set your boost ramp for traction for example in 2nd, but you're leaving power on the table in higher gears.

The simplest answer is a new Garrett G series. Buying a G25-660 on a 2.5 would be great and still not annihilate gearboxes, overcome commonly available tyres, create clutches that are too annoying to drive, and is physically compact so you get plenty of space to run lines to and from it.

Yes I know that I can control with boost by gear and that is my plan, but as mentioned in the scenario the 3076 is small enough to.build that power around 4 k but is limited to 500whp

just not sure how a larger turbo power delivery would be 

[robbo_rb180]

A rb25 with headgasket and studs, standard exhaust manifold with external gate mod, gtx3076 w/.82 rear on ethanol be perfect make 300kw on 16psi and will be linear. Pick an ecu and fuel system (ID1050 injectors and a Bosch intank pump around 400lph)
Been running a similiar setup for years in my sil80 (gt3076) and is very responsive and quick. 
More than enough to have fun and is great to drive.
 

[Kinkstaah]

On 5/21/2022 at 3:37 AM, Rand0b said:

Yes I know that I can control with boost by gear and that is my plan, but as mentioned in the scenario the 3076 is small enough to.build that power around 4 k but is limited to 500whp

just not sure how a larger turbo power delivery would be 

I understand - The turbos I mentioned are superior to the GTX3076 in every single way. One is a BW, and the Garrett G series are a flat out upgrade by the same manufacturer.

I have also owned a GTX3076 for direct comparison :p. 500whp is a lot and is just past the issue free fun threshold.

[Dose Pipe Sutututu]

On 21/05/2022 at 12:38 PM, Kinkstaah said:

I understand - The turbos I mentioned are superior to the GTX3076 in every single way. One is a BW, and the Garrett G series are a flat out upgrade by the same manufacturer.

I have also owned a GTX3076 for direct comparison :p. 500whp is a lot and is just past the issue free fun threshold.

Every single way? Over speed them momentary and see what happens with the BW.

372.8kW is not a lot... Crossing 400kW is. 

[Butters]

On 5/20/2022 at 7:03 PM, Rand0b said:

Agreed, that’s why I was asking on power delivery. If a 3076 is going to hit like a light switch 20psi ~4000rpm

i would think a slightly bigger turbo that maybe would start spooling 3500 and then gradually lean into 20 psi around 5k would be better power delivery?

just don’t kno what that turbo is

 See that's the cool thing about boost. Once you have it you can control it ... 

Very easy to tame down a small turbo's power curve vs trying to get a big turbo to come on early enough for the car to be fun. 

[Rand0b]

On 5/21/2022 at 10:53 AM, Butters said:

 See that's the cool thing about boost. Once you have it you can control it ... 

Very easy to tame down a small turbo's power curve vs trying to get a big turbo to come on early enough for the car to be fun. 

Agreed

This is a scenario of what I am willing to compromise with and see as acceptable 7163 is what a few have recommended. Example below

(7163) A 5psi :3k - 20psi: ~4k 

(8374) B 5psi :3.5k - 20psi ~4.5k 

(7163) if I am going to control boost to dial back a to make the power delivery more linear and hit target 20psi 500-750 RPM later so 20psi ~ 4,500 or 4,760 yes it would spool up quicker and range spread out over 1.5 a 1.75rpm 

(8374) could use adjustable cam gears to dial back a few hundred RPM so it could start spooling 3300rpm and then hit 20 psi 4300rpm. Yes it would take away from top end a bit but the factor of the larger turbo would still make more power per psi would put me closer to  my goals and get within the  acceptable street manners/spool range ?

not thinking of going from a 7163 to a 9174

Edited May 21, 2022 by Rand0b

[WR33KD]

Have you given thought to how much this is going to cost you. It’s all fine putting a $4k turbo on a car to make xxxhp but is it work it when a cheaper turbo will do the same. 
These big turbo names are just wank factor for 300kw. 
Next step is once you board of 300kw what’s next 

[joshuaho96]

On 5/21/2022 at 1:59 PM, WR33KD said:

Have you given thought to how much this is going to cost you. It’s all fine putting a $4k turbo on a car to make xxxhp but is it work it when a cheaper turbo will do the same. 
These big turbo names are just wank factor for 300kw. 
Next step is once you board of 300kw what’s next 

Just don't get bored with 300 kW, problem solved.

[Kinkstaah]

On 5/21/2022 at 8:08 PM, Dose Pipe Sutututu said:

Every single way? Over speed them momentary and see what happens with the BW.

372.8kW is not a lot... Crossing 400kW is. 

372.8KW is indeed a lot. I usually put the happy mark closer to 320ish kw, have a look at how many track days john richo has done on his unopened motor vs someone like yourself (not digging) where it did eventually go kablamo at 372kw. You also have to choose a bigger clutch, less grip, comes on 500rpm later... 370 is still probably okay, but I would personally choose a little less.

When I said 'better in every way' I was referring to the G Series Garrett, as well as the BW EFR.

On 5/22/2022 at 6:59 AM, WR33KD said:

Have you given thought to how much this is going to cost you. It’s all fine putting a $4k turbo on a car to make xxxhp but is it work it when a cheaper turbo will do the same. 
These big turbo names are just wank factor for 300kw. 
Next step is once you board of 300kw what’s next 

At 300kw the brand name turbos come into their own. Their whole 'betterness' is is in all of the areas that are NOT full throttle operation. Log the time driving where you're between 1000 and 5000rpm, at throttle openings 0-75% and compare that to the time operating at 100% throttle at 5000-7000rpm.

Even when you're belting it through the streets as hard as you can, 90% of the time is in the 0-75% throttle and 1000 to 5000rpm. This is why people rate the newer tech so much.

[Rand0b]

On 5/21/2022 at 4:59 PM, WR33KD said:

Have you given thought to how much this is going to cost you. It’s all fine putting a $4k turbo on a car to make xxxhp but is it work it when a cheaper turbo will do the same. 
These big turbo names are just wank factor for 300kw. 
Next step is once you board of 300kw what’s next 

Yes I am prepared and understand the costs, I think There may have been a misunderstanding of my question and this should clear it up for all do note that I originally mention I would love to hit

6-700whp on the DYNO

i do not expect to be at this level for fun street use , I want to know that I can turn it up and I am not at my ceiling

dyno run would be perfect conditions on VP race fuel or e85 / e98, turbo can be nearly maxed out. E85 is not easily accessible by me. Closest pump is 30 min in a direction I do not travel. So while I will go out to get it. It will also get pump gas so overall power will be down if mix fuels are mixed e50, e30, e10 ect 

looking for a turbo that I can hit. A 6-700whp on the dyno with boost being fast ramp 3-4,500rpm to hit 30psi. While on the street I could have e30,e50 / some mix of gas which if lower than e85 would have overall lower power output and I would have overall max effort rolled back to ~25psi with boost control being a linear ramp over 3-5500rpm

 

[Kinkstaah]

500rwkw in Aussie terms, 98 only, full boost at 3500-4500, 30psi?

Nothing exists with those requirements on a 2.5 on Petrol. Certainly would not be fun on the street unless your street is 200+kmh drag runs on the street. In the hills such a setup would be a mess, if it could exist.

[GTSBoy]

On 5/22/2022 at 9:11 AM, Rand0b said:

6-700whp on the DYNO

i do not expect to be at this level for fun street use , I want to know that I can turn it up and I am not at my ceiling

dyno run would be perfect conditions on VP race fuel or e85 / e98, turbo can be nearly maxed out. E85 is not easily accessible by me. Closest pump is 30 min in a direction I do not travel. So while I will go out to get it. It will also get pump gas so overall power will be down if mix fuels are mixed e50, e30, e10 ect 

This makes no sense.

There is absolutely no point in building an engine to make big power on a dyno then not to use that power for the vehicle's primary purpose, and WORSE, to suffer the compromises caused by the big power potential, aall of which make the car objectively worse in its primary usage model.

This is called cutting off your nose to spite your face.

Here's the thing - the things you say about big boost + torque made early putting stress into a motor are true. But, they are not true at the power level that actually makes sense on the street. At this magical 300rwkW (and I don't mean magical in a sarcastic sense, I mean magical as in it is actually magical that 300rwkW works well in a street application) you are NOT making enough torque at 3000rpm to actually do the damage you're talking about. At this level you want to ramp the boost on as fast as you can, because area under the curve = acceleration. The only compromise you need to make is to perhaps moderate your boost ramp for traction reasons.

Think about a 2.5L engine making good boost at 3000rpm (and only getting better from there up). Compare same to a 5 or 6 L engine running NA, and tell me that you would not want the torque of the 6L engine ALL THE TIME in the 2.5. Seriously.

[Kinkstaah]

On 5/22/2022 at 11:55 AM, GTSBoy said:

Think about a 2.5L engine making good boost at 3000rpm (and only getting better from there up). Compare same to a 5 or 6 L engine running NA, and tell me that you would not want the torque of the 6L engine ALL THE TIME in the 2.5. Seriously.

👀
muahaha.

My car is slower now than it was with a 2.8 and 433rwkw and I'd never go back.

[Rand0b]

On 5/21/2022 at 9:55 PM, GTSBoy said:

This makes no sense.

There is absolutely no point in building an engine to make big power on a dyno then not to use that power for the vehicle's primary purpose, and WORSE, to suffer the compromises caused by the big power potential, aall of which make the car objectively worse in its primary usage model.

This is called cutting off your nose to spite your face.

Here's the thing - the things you say about big boost + torque made early putting stress into a motor are true. But, they are not true at the power level that actually makes sense on the street. At this magical 300rwkW (and I don't mean magical in a sarcastic sense, I mean magical as in it is actually magical that 300rwkW works well in a street application) you are NOT making enough torque at 3000rpm to actually do the damage you're talking about. At this level you want to ramp the boost on as fast as you can, because area under the curve = acceleration. The only compromise you need to make is to perhaps moderate your boost ramp for traction reasons.

Think about a 2.5L engine making good boost at 3000rpm (and only getting better from there up). Compare same to a 5 or 6 L engine running NA, and tell me that you would not want the torque of the 6L engine ALL THE TIME in the 2.5. Seriously.

99% of people asking for injectors size feedback say the calculator said I need 850cc,  do they ever say should I lower my goals to get the 750cc? what do most car guys say? , get 1000cc so you have room to grow you are going to want more power later on. It’s one less thing to purchase . That is what I am trying to accomplish. Finding something that has good street manners, potentially hit a number between 6-700whp on a Dyno 

It could end up being Turbo A on e85 622hp  maxed out on the dyno. Then  running  e30 on the street it’s more like a mid 500whp car and the turbo has  fantastic street characteristics.

or it could be Turbo B on e85 689whp maxed out on the dyno. ends up being a  low 600whp car when on e30 and has acceptable street characteristics for its overall power

I haven’t said 700whp+ At all times. I could drive like this forever OR could get bored in a year and decide only use e85 and now the car is at max effort And if I take it to track it will perform and I do not have to purchase a new turbo, upgrade injectors get a new tune ect

You said ‘tell me that you would not want the torque of the 6L engine ALL THE TIME in the 2.5. People have a low and high boost setting. Why wouldn’t you want to always be on high boost at all times if the car is capable to perform of that level? What’s the purpose of the low boost setting?

I don’t kno what you are referring to with ‘you are NOT making enough torque at 3000rpm to actually do the damage you're talking about’ I haven’t referred to damage. I have referred to power delivery with traction as the underlying item. 

Edited May 22, 2022 by Rand0b

[GTSBoy]

On 5/22/2022 at 11:29 AM, Rand0b said:

99% of people asking for injectors size feedback say the calculator said I need 850cc,  do they ever say should I lower my goals to get the 750cc? what do most car guys say? , get 1000cc so you have room to grow you are going to want more power later on.

That's a logical fallacy. Injector headroom with little to no negative consequences is absolutely not equal to overbuilding an engine to make dyno queen numbers, then not even intending to use that power for real.

On 5/22/2022 at 11:29 AM, Rand0b said:

You said ‘tell me that you would not want the torque of the 6L engine ALL THE TIME in the 2.5. People have a low and high boost setting. Why wouldn’t you want to always be on high boost at all times if the car is capable to perform of that level? What’s the purpose of the low boost setting?

Have you missed the point that badly? Street car? Then torque is the boss. Power numbers only arrive in the top half of the rev range. Torque is useful everywhere.

And low boost is obvious. That's for your girlfriend who usually drives a FWD shopping trolley. It's for the guy at the tyre shop who does the round the block after the new rubber goes on. It's for the valet, should that ever happen. It's for wet weather.

On 5/22/2022 at 11:29 AM, Rand0b said:

I don’t kno what you are referring to with ‘you are NOT making enough torque at 3000rpm to actually do the damage you're talking about’ I haven’t referred to damage. I have referred to power delivery with traction as the underlying item. 

In that case you have quoted common wisdom without understanding where it comes from and why it originates.

If you make massive torque down low, such as you could/would with a turbo setup able to make stupidly large power and somehow get a lot of the boost to come in as early as possible..... then you place extremely large mechanical loads on conrods and bearings and can hammer them so badly that they actually do get damaged. There is also the thing about squeezing all the boost you can into an engine in the region around peak torque being a bad thing, and that is because this is where you will cause detonation.

So don't tell me you didn't, because you did, even if you didn't realise it.

[Ben C34]

Lol.

Use nitrous on the dyno for the glory. 

Size turbo properly.

[Lithium]

On 21/05/2022 at 10:08 PM, Dose Pipe Sutututu said:

Every single way? Over speed them momentary and see what happens with the BW.

Wat.   

Lets just break this nonsense down shall we:

1) I don't know anyone who has actually broken an EFR directly, I *do* know plenty who have run them off the max compressor speed.
 

2) ^ You read that right, the "failure" warning is misattributed to a magical turbine speed limit but the actual max speeds published are to do with compressor max speed - there is no max turbine speed published for the EFRs.  If there is a turbine failure, the thing would have been WELL past the max compressor speed so whoever has put the car together has f**ked something up if they've got to the point the EFR fails due to turbine speed.

3) Taking the top two points into account, you're basically saying "Sure the EFR is a way better performing turbo than the Garrett GTX equivalent, but if someone is incompetent with the match and installation there is a remote chance the EFR will fail sooner than the Garrett."

Basically the EFRs are better.  But get a Garrett if you have legit concerns that you are an idiot, it will also fail if you poorly match it- but you might have a longer grace period to work it out.
 

Edited May 22, 2022 by Lithium

[Rand0b]

On 5/21/2022 at 11:46 PM, GTSBoy said:

 

I am not trying to argue

I am rebuilding a engine that needs a rebuild, I am opting to upgrade parts now since I don’t know what power I would want potentially 2 or 5 years down the road.

I’m agree on engine stress under load with added forced induction. I have referred to power delivery As to the wheels. I do not want a turbo to be 3psi 3k to light up 25psi at ~4k and all it does is spin the tires, that is what I am referring to as power delivery. If I can get that 6L pull feeling Hells yea I would want it all the time but I know I may need to make it linear to ensure proper traction.

so what would you say a good turbo would be?

e85 dyno into 6xxwhp

but still acceptable to drive on the street  if not on e85 (e30, e50)

 

Edited May 22, 2022 by Rand0b

[Dose Pipe Sutututu]

Ok EFRs are better, happy?

They're the best. Don't buy anything else because they're shit.

According to know it all @Lithium I'm an idiot.

[Murray_Calavera]

On 5/22/2022 at 2:59 PM, Rand0b said:

I am not trying to argue

I am rebuilding a engine that needs a rebuild, I am opting to upgrade parts now since I don’t know what power I would want potentially 2 or 5 years down the road.

I’m agree on engine stress under load with added forced induction. I have referred to power delivery As to the wheels. I do not want a turbo to be 3psi 3k to light up 25psi at ~4k and all it does is spin the tires, that is what I am referring to as power delivery. If I can get that 6L pull feeling Hells yea I would want it all the time but I know I may need to make it linear to ensure proper traction.

so what would you say a good turbo would be?

e85 dyno into 6xxwhp

but still acceptable to drive on the street  if not on e85 (e30, e50)

 

I'm not trying to derail this thread, but I'm curious why you are talking about driving the car on e30 or e50? Surely if you have access to e85, you'd just run that all the time and only drive on 98 when you don't have access to e85?