Thanks for tihis TurboJ - I think <img src="/forum/images/graemlins/crazy.gif" alt="" /> <img src="/forum/images/graemlins/laugh.gif" alt="" />

This might clear some stuff up - Garret turbo explanation .

I thought the GT28RS had a 62mm compressor which makes it a GT2862RS in the new terminology anyway?

John

thanks john

would this be the GT 28r/rs hybrid that we are all thinking about?

Joe <img src="/forum/images/graemlins/smile.gif" alt="" />

Joe, the hybrid R/RS is a Torque Italia spec so there won't be an official Garrett designation. As it uses the RS compressor the relevant map is the same as our standard RS turbo.

hmmm I did wonder ,...I wonder though what this smaller gt2860r Garrett are selling is then?

Its quite confusing all the changes, ATP is a lot easier! <img src="/forum/images/graemlins/wink.gif" alt="" />

Joe

I put myself the question nevertheless because I am lost a little in all these turbos
GT2860R
GT2860RS
GT2871R
GT2876R
and with the various diameters of the turbines <img src="/forum/images/graemlins/confused.gif" alt="" />

Does anyone have the GT Hybrid R/RS installed?

I am assuming that that price will be quite a bit dearer for this hybrid, including fitting? A figure of a £1000 comes to mind <img src="/forum/images/graemlins/confused.gif" alt="" />

However i guess it is the best of both worlds

I now have no idea what turbo I have <img src="/forum/images/graemlins/crazy.gif" alt="" /> <img src="/forum/images/graemlins/confused.gif" alt="" /> <img src="/forum/images/graemlins/grin.gif" alt="" /> <img src="/forum/images/graemlins/laugh.gif" alt="" />

Which one?

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2860R_707160_5.htm

or

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2860RS_739548_1.htm

I thought the Torque Italia one uses a GT28RS 62mm compressor and the GT28R turbine wheel?
Maybe I'm just confusing everyone even more <img src="/forum/images/graemlins/laugh.gif" alt="" />

noooo <img src="/forum/images/graemlins/crazy.gif" alt="" /> <img src="/forum/images/graemlins/crazy.gif" alt="" />

please remove this post please <img src="/forum/images/graemlins/crazy.gif" alt="" /> <img src="/forum/images/graemlins/confused.gif" alt="" /> <img src="/forum/images/graemlins/frown.gif" alt="" />

That's what it says on the TI website!

Reading a bit on the Garrett site, it seems that the most important characteristic of a turbo is the A/R on the turbine side (I'm an expert after reading the Turbo 101 tutorial on their site <img src="/forum/images/graemlins/wink.gif" alt="" />). If you look at the ATP Turbos most people have bought, either the ATP - R or ATP - (.64)RS and the TI hybrid uses .64 as well ... maybe there's not that much difference between the turbos after all? Will a .64 RS really flow that much more? I know the trim of both wheels is also important (there's b*gger all difference between the TI hybrid and ATP R on this) and the ATP RS stands out a little on the trim front.

Looking at the specs (and the design features that matter), you could conclude that:
1. there's bugger all differnce between the ATP R and the TI R/RS hybrid
2. there's not that much difference between the ATP R and ATP .64RS ... although u'll probably be able to flow a little more on the RS due to the turbine wheel?

Perhaps the RR figures don't back this up, but then again maybe the people who bought an RS have their cars in a more aggressive state of tune? It would be really interesting to RR the same car with the same setup and only change the turbos!!

I'm probably talking b*llox <img src="/forum/images/graemlins/smile.gif" alt="" />

don't forget different compressor or turbine wheels for that matter have different characteristics, so size and trim only tell half the story. Two compressor wheels can be the same size and trim but have completely different compressor maps.

john

I'm not gonna even try to think how wheels the same size have different characteristics <img src="/forum/images/graemlins/smile.gif" alt="" /> If we can just get the maps for the TI Hybrid, we have all the facts!

The RS has a slightly bigger compressor wheel, but a lot bigger turbine wheel, that's why it can flow a lot more air, and the map demonstrates this. <img src="/forum/images/graemlins/smile.gif" alt="" />

Joe

The turbine wheel is a good bit bigger, but with the .64 AR option on the turbine side, how much do you lose compared to the larger AR housing, what's the trade off? It would be nice to have access to a design tool that lets you overlay the maps, see how varying the parameters chages everything etc. Any mechanical engineers into fluid dynamics for a living that could help me out <img src="/forum/images/graemlins/idea.gif" alt="" />

David, yes that would be nice.

It appears that you will lose 5-600rpm spool-up between the 0.64 and 0.86 housings, but the 0.86 does flow a little bit more at the top end.

for instance, Flea and myself have virtually identically tuned cars, the only difference is that Flea runs the 0.86 GT28rs and I run the 0.64 GT28rs.

His car ran 370bhp, and mine ran 363bhp, but on different days, and oddly mine ran more at the wheel, so its hard to compare. We both drove each others cars and raced them <img src="/forum/images/graemlins/wink.gif" alt="" /> <img src="/forum/images/graemlins/laugh.gif" alt="" />, and I think fleas car was slightly quicker 6000-7000rpm, but my car had better spool-up, so overall the race was dead even 50-140mph!

Have a read here, it might be of interest

Frag vs Flea.

Joe

Hmmm, confusion appears to be growing! The TI hybrid is exactly that therefore Garrett don't make "it" and won't have a specific listing for it! That said, we know that it utilises the same 62mm trim compressor and housing as the 28RS which quite a few of us on here use e.g. Joe and me. The benefit of this hybrid turbo comes from the smaller turbine wheel which allows for increased low down response akin to the 28R while gaining a bit more top end from the larger compressor. It's doesn't generate quite as much low down positive boost as the 28R or quite as much top end as 28RS but it's positioned to take advantage of the middle ground <img src="/forum/images/graemlins/smile.gif" alt="" />

In reality there isn't a huge amount in it on the road. Markus is quite exceptional in that he has maxxed out the TI hybrid with increased flow from headwork and greater mid-range boost due to forged internals. It's an awesome package especially with the Nitrous <img src="/forum/images/graemlins/laugh.gif" alt="" /> On the road there is nothing between my coupé and his above 3800rpm but if we go from around 2500rpm in gear then the smaller turbine housing i.e. 0.64 to 0.86, and smaller turbine wheel means Markus spools a fair bit quicker and comes on boost a little quicker. Our road tests showed this equates to 1.5 car lengths in 3rd gear.

Joe and I have done similar tests with our tune being more closely related i.e. no headwork or forged internals for increased mid-range boost. The only significant difference is our turbine housings being 0.64 and 0.86 respectively. This means, in-gear, Joe gets increased spool which in 3rd gear from around 2500rpm translates to a car length and comes on boost marginally quicker <img src="/forum/images/graemlins/smile.gif" alt="" />

What this means is I need to make sure I am above 3500rpm if I ever race these lot!! <img src="/forum/images/graemlins/smirk.gif" alt="" /> <img src="/forum/images/graemlins/laugh.gif" alt="" />

That said, if you look at the PTS graphs, Joe seems to be making more power at low revs than Markus, - or am I going cross eyed with all the lines?

The graphs are never going to be that accurate as they are done on different days i.e. temps, heat soak and even different tyres. Bearing in mind Markus is unmapped and therefore doesn't benefit from increased igition advance and is also running slightly rich. On the road is where you can tell and Markus as a small advantage low down <img src="/forum/images/graemlins/wink.gif" alt="" />

Given the choice now I would go with a Torque Italia hybrid as it has the mix just about right... and the price is pretty keen too! <img src="/forum/images/graemlins/smile.gif" alt="" />

I'll give Barbz a ring so <img src="/forum/images/graemlins/cool.gif" alt="" />

I have not had the chance to fully test my TI Hybrid but I’m pretty sure it is the BEST turbo for my level of tune as I want all my power in the mid.

The way I see it is this:
GT2560R (.64) = Very Fast Spool Up, good mid and weak top end, rated to 330BHP
GT28/R/RS (.64) = Fast Spool Up, great mid and good top end, rated to 350BHP
GT2860RS (.64) = Slow Spool Up, good mid and great top end, rated to 360BHP
GT2860RS (.84) = Slower Spool Up, great mid and great top end, rated to 360BHP
GT2871R = Laggy Spool UP great mid and very good top end rated to 400BHP

So in conclusion you must know what work you are doing to your engine and where you want your power band to be before committing to any turbo. Every turbo has its good and bad points it's just down to your preference.

Your analysis is a little over-simplified and the figures aren't quite "correct" but agree that the TI hybrid would be the best bet for what you want <img src="/forum/images/graemlins/wink.gif" alt="" />

TurboJ, to put this into perspective with straight induction etc, I get 1 bar at 3000-3100rpm with the gt2860rs (0.64) which is only just over 100-200rpm worse than my GtI-R hybrid.

Joe

Well best to keep it simple as we don't wanna start a major confusion again <img src="/forum/images/graemlins/laugh.gif" alt="" />. And i'm sure you will agree with me that it all depends on where you want the power band and engine tunning stage. How do you know what i want you been peaking at my spec sheet? <img src="/forum/images/graemlins/wink.gif" alt="" />

Yes thats all good and well i'm not saying its bad but if you had the TI Hybrid or the R it would spool up even quicker. I just put them in order of spool up thats all. As i say it all depends on the rest of your car.

Indeed <img src="/forum/images/graemlins/cool.gif" alt="" />

I might have considered the TI hybrid if it had been around when I got the GT28rs, but noone had fitted the o.64 at the time so was a bit of a gamble <img src="/forum/images/graemlins/wink.gif" alt="" /> as my main aim was a strong road going/trackday turbo, I didnt want it to be any laggier than normal ,but had to accept a little bit of extra lag. The only downside is that boost comes in hard and fast which can put too much strain on the GTA/Walkers clutch.

regards

Joe <img src="/forum/images/graemlins/smile.gif" alt="" />

Hi all,

for my configuration, I've in more a SI and a pro allow intercooler. I think that the gt28r/rs 0.64 is the most adapted

Do you also think?

thanks

Yes the TI hybrid would be very good with those mods, just need to check the fueling before you go boosting it everywhere <img src="/forum/images/graemlins/wink.gif" alt="" />

As my car is totally unmapped i am only running 1.25 bar at the redline with whatever ignition advance is on the chip im running. Also in the midrange the fuelling is slightly rich and from idle upto 3k it is very rich indeed!!!

Im planning to get my car mapped asap and then i will run 1.4bar at the redline which shud bring my power figure up slightly also with the ignition advance i shud see a few more horses.

the rs turbo alone feels like an on/off switch...u either have nothing or everything in 1 hit. My turbo benfits for the response of the gt28r with the combined top end power of the rs. Also i do believe my low end torque will be even greater once mapped as im convinced PTS' rolling road could not cope with any type of big power car with low end torque. They tried at least 6 times with the nitrous <img src="/forum/images/graemlins/smirk.gif" alt="" /> to get the car to stop wheel spinning and i had to turn the boost down and bak the progressive controller right off to come in as late as possible. The car even wheel span without nitrous at first and i run 235 wide semi slicks.........

sorry to go on...but off boost my car is very torque indeed and drives like a powerful n/a car (down to head work and turbo spec)....and when i need the power out of a corner or whatever i dont have to wait for boost <img src="/forum/images/graemlins/wink.gif" alt="" />