Bazman

I want a custom spec turbo to replace what I have when it fails next. I can email turbo makers privately but do it online for public interest as there are others like me who want a rear mount to come in early but not have so much back pressure and get more top end.

I am willing to pay a premium to achieve high flow per lb of boost and get more boost at lower rpm than a shelf turbo can give by going bigger.

I'm running a rear mount STS ball bearing 6275 T4 0.81AR. The system is based on a universal STS kit but we upgraded everything.

We use race quality 4 into 1 headers with merge collectors that step down from 2 x 3" into a single 3" pipe to the turbo. Exit is a short straight through muffler 3"

Car is per the pics and video link (wet track and street brake pads)

Engine is a 2013 LS3 with 218/222 cam on 114/116 and 0.561 lift, it also has 040 Cometic gaskets. I run a state of art Aquamist water/meth system, that injects from 2lb boost up. I run on the equivalent of your 93 octane (we call it 9. Car weight is over 4000lb with me in it, and it runs a RPM Stage 6.5 4L65 with a 2600rpm Precision converter with 800rwhp rated lock up. Final drive is the stock 3.07:1 with a Harrop Tru Trac.

I can email a dyno pdf which shows I have at least 4lb boost by 2750rpm and 10lb by 3000rpm. I'd like to get a bigger turbo that can keep the fat power curve from 2500-2750rpm but breathe more up top.

As it is a rear mount I need one size down AR to work compared to a front mount.







Makes 630hp, should be 800 at 10lb but don't want to lose my bottom end - it's too good to sacrifice.

Who can size and make something that will do the job and be reliable? I will give full props online to anyone that can get this right

Bazman

This application will not suit the cheap turbo high volume sales shops, this is going to require someone who knows their **** and will take the time to do their homework.

Bullseye? PT? FI? ??? just run a stock EFR9180?

I'll pay a consulting fee up if I need to, I want to get this right. I have serious money in this car so don't want some cheap *** "shelf" solution unless it's actually a very smart one. Area under the curve is important with tall gearing and a heavy car.

I'm thinking of going to a stock stall speed to reduce trans temps too. What I lose on the start line would be made up for by greater efficiency. Should have put a T6060 in and been done with it, but with over $10k in the trans etc by now I want to get some use out of it lol

Bazman

For those that don't know where NZ is, we're where the hobbits came from

stevieturbo

Best to phone the turbo guys direct, not all of them read this forum etc.

Forced Inductions
Work Turbochargers
AGP Turbo


or the place I bought my pair from,

http://www.spsturbostore.com/

It's a waste of time browsing websites, you're best speaking to a human being and discussing your setup and needs.

thendawg

+1 for Work. Reed is a great guy and can put together pretty much anything youd want or need (well turbo wise anyways)

I8UR4RD

iTrader: (16)

+1 for Jose' @ Forced Inductions. his wheels are setting records.

MUSTANGBRKR02

iTrader: (91)

Three good options right there.

LASTLS1

iTrader: (7)

I've had good luck with forced inductions.

Bazman

Yeah well emailed the most often recommended firms and got no response. I don't have time to phone around half a dozen firms and repeat myself, I run a company, can afford what I ask for, and I don't deal with folk who can't be bothered with emails as that is a sign to me they are not organised or old school.

Bill from Bulls Eye Turbos is the only one that bothered to respond, and I'm impressed so far.

They have a great facility and their batwheel billet turbos offer more area under the curve which is exactly what I need. I am satisfied they know what they are doing and they have records to prove it, so let's see before we start with the flying unicorn jokes. lol

A bonus is that Bill is very familiar with remote mount turbos, so that will be a big help.

Any rightly sized turbo can make the top end, it's doing that while maintaining the bottom end that I wanted, and I think Bulls Eye will give me that. I'll likely go to twins and be done with it, that'll help lower rpm boost start even more. Should be a fun project for later in the year, I'll likely move the turbos forward and remove the rear seats and fabricate space right there, add a cage and fuel cell etc.

stevieturbo

I dont think there is any real evidence to support the claims the batomowheel is any better than a regular billet wheel.

In fact there has been some to suggest it is worse. Only a small amount though.

I agree the email thing is frustrating, as when we arent in the US, it is by far the most convenient means of contact...but then I guess these sellers also get hundreds if not thousands every day, which can make it an almost impossible task to get through them all.

When I contacted Work Turbochargers and Southeast Power Turbo, both communicated very well by email, very helpful and prompt.

In the end I went with SPT puerely because they offered a new genuine BW 64mm billet wheeled unit, and not something of an unknown origin, or a turbo made from bits and pieces gathered from everywhere.

That's not to say the others wouldnt work, but genuine product is usually best.

V-seriesTech

iTrader: (5)

Bill Devine will take care of you, if not Reed or Jose or Mike Frankie. In random order.

Bazman

Yes times have changed a lot since I started dealing with US businesses from the other side of the world in the 90's. It's a different world now.

re the batmowheels - I've seen good evidence they work in some applications, so I'm hoping they work in mine. The graphs I've seen so far where nothing was changed but the turbo wheels have all shown a fatter mid range, some have a fatter bottom end as well, and they all made a small increase up top, some made a big gain.

Rob Corujo holds the world record and runs them, and Wild Bill himself is no slouch here running a 4.14 in 10.5 small block class, and on track to run a 3.9


their castings and machining is first class and I am qualified to say that because I was once CFO of a foundry heavy engineering company and we could not sand cast to the precision Bulls Eye is doing, in fact nobody could sand cast to that tolerance. That's why they went a more expensive route to get that quality.



In the end there are many ways to cross the line first, but I love to see genuine innovation, and am happy to support someone doing it well.... especially when they're prepared to communicate lol

Mel Carlson

I don't understand why people do rear mounts. such an innefficient way of using a turbo.

stevieturbo

For the base STS that seemed to start it all, it was largely cost, emissions control, rules etc

It was a cheap turbo kit for a mild power upgrade that didnt inflict too heavily on places that werent allowed to tamper with emissions control stuff.

But it really does seem to have taken off, despite it being the worst possible design of a turbo system.

If it's for drag racing where spool isnt really a concern, then I guess they can still work pretty well.

Bazman

There was a time I'd completely agree. Then I did one, and now I know from experience why.

For every negative you can give me why not to do one, I can give a positive why someone might want to.

No it won't spool quite as quick or as early, no it won't make quite as much power as a properly built front mount will. But a good rear mount will beat most of the many poor to average front mounts out there. So just having a front mount does not mean you have a better setup. The differences are not huge.

For me, I like to road race, and having 2 glowing red hot hair dryers up front in an engine bay where the engine and exhaust are already hot is just a bad idea. Good luck developing a twin front mount that does not heat soak after a few hot laps. I'm sure it's been done, but not near as easily as a rear mount.

I also like the idea of NA efficiency off boost. Turbo logs and tight shorty headers on a front mount don't even come close to the full race headers and merge collectors I can run. To those that claim I should be running stock manifolds into a 2.5" single to speed up spool - yeah right. Good one. You do that. I'll sacrifice 200-300rpm spool for the radically improved efficiency of free flowing plumbing. Remember the turbine will always be the restriction, so getting maximum flow to it is smart not stupid.

I can spool from a dig, do I need it any faster? I can use 100% of what I have, would faster spool help? NO, the tires will blow it off. I can even get most of my 630hp down in the wet. Try that on a twin T04 front mount.

Horses for courses and I can use what I have and nobody beat me in the wet. In the dry, I'll still be there after a few hot laps, will your front mount?

it's all good

as for STS - great concept for some applications and goals, poor quality however for long trouble free operation IMHO, we upgraded almost everything that came in the kit. I still think they should offer a top shelf version

stevieturbo

You can try and convince yourself that a rear mount is better, but many of your positives are almost delusions.

As for any reference to poor to average designs....rear mounts always fall into those categories simply by design.

You may suggest about n/a efficiency off boost...really no odds there. If you stick a cork up your exhaust with headers, you still have a cork up the exhaust so any gains would be negligible, and what is lost through energy to drive the turbo...well it just makes it a bigger negative.

As for spool from a dig....poor boost control is poor boost control. Trying to justify lazy response saying it helps put the power down is once again just deluding yourself.
With a well designed front mount you can easily ramp in boost however you want. With a laggy rear mount you dont have that option, it's always slow.
And the fact it only makes 630hp by your own statement, maybe that's design, tuning, whatever, but a front mount will allow you to make more power, it will be more efficient and do it with far better response. None of those things are negatives
If you chose to, you could easily dull that response with tuning and boost control though to make it feel more like a rear mount.

Really there are almost no genuine benefits to a rear mount that can be properly justified.

Even the heat soak you mention whilst racing. If you're going slow enough for heat soak in the engine compartment to be an issue whilst racing, you have bigger things to worry about, unless it's a snail race.

Yes heat soak when stationary can be a concern, but with some common sense and modern heat management materials...it is no longer an issue either.
Dont forget...a lot of that heat energy is used to drive the turbo. So we dont want to lose it regardless of where the turbo is.

But at the rear, again through design a lot of that heat energy will be lost. At least up front we have the option of using it.

chuntington101

Might sound a bit daft but have you concidered going supercharger rather than turbo? You are going to be throwing a decent amount of cash to get a good turbo, ESP if you want something a little custom. Why not ditch the turbo and go SC? The SC should be more consostant for use on tracks than a turbo. Plus you already have headers etc.

Just an idea!

Bazman

edited - your post reads better when I'm sober

hahaha

Bazman

Bro, I've always choked over SC because of the loss to drive it and the front weight, but your logic is good. I'm a turbo fan thru and thru due to its faster spool. I have 300rwhp by only 2700rpm. no ls7 has that, no sc will give that. But I get your point, and a stroker with a whipple, or what I have with a procharger is an option if only because I could dial it in so the tires hook. Turbos hit too hard once sized right.

stevieturbo

What a ridiculous argument. Where have I ever challenged you to a race in my road car ? On any surface, at any venue over any distance ?

I havent, so where on earth has that come from ? And what has given you the very misperceived perception I'm a drag racer ?

I use my car for many things, and yes one of them is occasionally drag racing. And what ? Will you challenge me to race to the local supermarket too ? Or when taking the car for a drive ?

My car is not a race car, it's a car purely for my own personal enjoyment that I can use for whatever I want. And that's a hell of a lot more road use than any form of racing.