IHI RHB5 or T2 /T25
Turbo Mini Forums

I've read on one of the topics around here that there is a fair bit of lag on a T2 (i'm assuming it'll be the same if not worse for a T25).
So on a 998cc project which would be recommended, an IHI RHB5 or a T2/25? (opinions seem to be divided from reading other posts...)

Also does the IHI come on anything besides the Charade GTTi?

http://mini.twisted-design.net/blog/

Not being funny chap but you need to make some decisions for yourself............its no good asking on here for every last thing, its going to be YOUR car at the end of the day, so choose the things you think will suit YOU best.

Edited by Tom Fenton on 27th May, 2005.

Lag on a t2? none that I've noticed! there are only a handfull of people on here that have ever used both, t2, and t3, most people just go of what they have heard. I have tried a t3, I wouldn't really describe that as laggy top be honest, but the t2 is a 1000 X better. but I all supose it depends on what t2 your talking about. I have run the r5gt turbo, and the silvia, I'm now going back this year the the r5gt turbo

Team www.sheepspeed.com Racing

T2 lag?
errrrr, wher'd you get that from - certainly not on this site!
Try and imagine a supercharger power delivery. Now stop right there. take a 1mm step back, and you have the R5GT spec turbo power delivery. Take 100 steps back and you'll find the t3 power delivery.


IMO the T3 on the metro didn't suffer from 'lag' really, so much as poor response due to a high inertia... You may start to notice 'lag' once you up the size of the turbine housing on a T3 mind!

Will you guys shut up about mocking the T3. :$

TurboDave:
"about t2 the gt turbo T2 good do the job , but he'll give you lag and a lot of lees spooling than the rhb5, it's all the difference between something that work and something that really doing his best"
found here: http://www.turbominis.co.uk/forums/index.php?p=vt&tid=4777 posted by fab

I know the T2 seems to be the recommended turbo - but I have read that for a 998 the RHB5 is prefered. Just trying to get a feel before I decide which one to spend my money on - there isn;t that much of it.

http://mini.twisted-design.net/blog/

perhaps dave didnt see the 998 part

oh yes, a 998.
And you're considering a T25? Well if we are talking about a 998turbo you can reduce your options by 33% straight away - ie forget the T25.

The 0.35 turbine housing on the R5GT will spool up just fine in a 998 given how well mine worked in my 1275, and not be restrictive at all - basically a well matched unit for a med/high (10-16psi) turbo 998.

If all you're looking at is <10psi, take Fab's advice and source the IHI.

Hi Everybody,

Just joined what looks like a brilliant web site.I have been sprinting a road legal Turbo mini for 5yrs,up until last year a 1293cc with a T3 on injection.This year i'm running a 998cc,with injection again,using an IHI RHB5,I'm using an Emerald ecu for fuel and sparks.On Dave Walkers rolling road the car was making 112bhp, with 123ftllbs of torque.The IHI seems to spool up very quick compared with the T3 on the old engine,and makes peak torque at 4200 rpm.The IHI requires a lot of fabrication to make it fit,the waste gate/exh turbine end has to be fabricated from scratch,it is quite a tiny thing compared to the T3 and looks like at a push it might fit with out the need for a bulk head box.Ive photo's of how I went about fitting it,and would gladly email them to anybody interested or post them on this site.

Hi Graham you in the Midlands ??



Karl.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

Hi,

Yep, i'm in the midlands,I see you have a picture of my car,looks like it was taken at Curborough.I only live 10 mins drive from Curborough so it's very much my local circuit.That photo is of the old engine with my home made injection system and the throttle body made from an old SU.I would still be running it but the class rule changes saw it outlawed.
The new engine at first glance looks very similar,but in actual fact is very different,think only the intercooler,g/box and radiator are used again.The new 998 motor makes more power and torque.R u local to me?

Graham could I see pictures of your new engine?

TurboDave - what sort of psi would be recommended for a fast road car? I doubt this car will ever see a track as there is little to no mini scene over here.

http://mini.twisted-design.net/blog/

Is that the green Mini that was in Miniworld a couple of years ago? I remember home made injection etc.

Hi, Snowfruit and Vegard.

I will gladly sent you pictures of the new engine,once I've worked out how to attach them to this forum.I might be able to build a decent Turbo engine but am buggered if I can work out how to put my pictures on the site.I might have to send them to you via e-mail,I can just about sort that.
The car did appear in Miniworld mag a few years ago,July 2002 I think.The car hasn't changed at all since then,but it's had numerous injection set ups,and now a 998cc motor instead of the 1293cc.Getting injection to work properly on a A series is a bit of a pain,think I've got it sorted now thought,with the help of Dave Walker at Emerald.

Graham.

Graham, I've talked about you alot in the past to Dave Walker, who I must say thinks a lot of you. I also running emerald M3d on my mini turbo, but I am still using the SU at the moment. Injection is somehting I will be looking at next year I think. Any tips?

Team www.sheepspeed.com Racing

feel free to email them to me or alex and we'll gladly host them and stick them in a post for you to put words around

iain@turbominis.co.uk

Hi Jimster, Iain,

Thanks for the offer of posting the pictures for me,I will sort them out and email them to you.
Jim,
I've struggled with injection for years and have finally come up with a solution that really seems to work.I've tried putting the injectors in the MG Turbo type manifold,as close to the head as possible,which according to the experts is the best place to have them,but problems of cylinder robbing manifested itself,the picture of the engine above was with this set up.The car ran brill,but never really realised its full potential.
I tried then injecting it much futher back in the inlet tract,the theory being the fuel/air had time to mix and the more "mixture" there was in the longer inlet tract for the cylinders to share and cure the cylinder robbing.It made about the same power but was totaly undriveable.
"Robbing" occurs I think, because most management systems fire the injectors in batches once per cycle.This is fine on an engine that has an injector per cylinder,but when the cylinders share an inlet, 1 cyl takes out what it wants,when the other cyl comes to take what it wants there is nothing there or very little there,the engine runs,but you can end up some cyls running weak.
My latest system uses a jenvey throttle body( only brought this because I didn't have time to make one) with 2 injectors.These injectors are fired at different times,so each cyl gets what it wants when it wants.The latest Emerald management system has the facility to do this.
I use Cosworth yellow injectors,they are cheap and a pair is good for 130-140hp.
Hopefully if I can get the pictures on the site my set up will be self explanitary.
My personal view is that injection is the way forward for big hp Turbo's,the fueling/ignition can be set up to perfection throughout the rev range.Management systems ar'nt cheap,but neither is an engine melt down,caused by the fuel leaning off because the needle in the SU needed a bit more filing.

Graham.

Graham, some good reading there. Where have you mounted the injectors on your current engine? When you say "latest Emerald management system " is that the m3d, or is that there new smaller ecu?

Team www.sheepspeed.com Racing

Hi Jim,

The management system I've got is there latest silver one,think it's called M3DK,I used to use the black coloured one,think that was called M3D,but as you know Karl can make any of the systems do whatever he wants.I'm sure the system you have will be ok.Whilst on the subject of management systems,for anybody else who is thinking of getting one,and I'm sure Jim will agree.the aftersales/set up side that comes with the Emerald systems is superb.Dave Walker and Karl Paton( electronics expert) are real enthusiasts,nothing seems to much trouble,there system is very d.i.y friendly.I've heard a few horror storys about other systems that are around the same price to buy,but the mapping service,problem sorting can cost an arm and a leg.

The injectors in my latest system are in the throttle body.I've sent Iain some photo's which should appear on the site soon,hopefully these will show some things that are difficult to explain in words.
I've used the MG Metro inlet manifold with a home made adapter for the throttle body.which ends up in about the same position as the carb would normally.

Graham.

I think Grahams setup is very close to the Emerald Midget setup on their website.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

il post them tomorrow

Interesting stuff Graham.

Jim - In response to the question you're thinking; If you can get enough fuel into the engine at the right point, you can easilly make big power with the A-series.


Making a short manifold as this concept has done if definately one way. Sounds like emerald have (at last!) included a setting that allows them to shift the injection point to where is is optimal - eg injecting the fuel say 10degrees ATDC @ 1000rpm, such that by the time the fuel reaches the port divider, the inner valve is fully closed.
For an engine running at tickover, it's that simple...

However, the air velocity in the port changes, such that at say 6000 rpm you need to 'delay' firing the injector by (approx) 20/30 degrees, hence actually firing it some 30/40 degrees ATDC (although this depends on the actual port velocity and length from the injector to valve). Being able to simply tap away and move this injection point is so much better than moving the injectors so far back that an ugly looooooong wet manifold is created, and the puddling/emmisions problems that is generated (as Graham highlighted).

Also, I'll guess they're now firing the injector(s) every 180 degrees, rather than the 360 degrees they were originally (and instead of the 720 degrees of a conventional aftermarket batch-fire ignition). Further, the two injectors are (I'm pretty sure) wired up together - hence you're getting a huge slug of fuel that can 'fit' inside the very short remaining injection window.

Although running two injectors leaves you reduced sensitivity at tickover, this is good in that you're firing the injectors well after the inlet has closed, so charge-stealling is going to be (in theory at least) zero at tickover... If the injectors are well maintained units with fast response, it shouldn't be an issue mind (and lots better than a carb).

Another advantage: Firing the injectors every 180 degrees does mean the fuel that leaves the injectors will in theory be carried by the charge air straight into the appropriate cylinder. I wouldn't be too surprised if the changes in air velocity / lengh of the inlet tract / corners & bends in the inlet tract / etc will probably do their best to mess this theory up however?

The ideal 'further optimisation' on this setup would be for Graham / yourself to go back to his original manifold, but have FOUR injectors - each pair next to each other, right up close to each manifold flange. If there was sufficient 'spare' pins in the ECU, this could easilly be made fully sequential using a cam sensor, such that each pair of injectors was fired right at the appropriate time. Port wetting would also be reduced to a minimum. Although this is known to not give huge benefits (other than slight emmision and economy increases) on a conventional 8-port engine, the A-series might well lend itself to this due to the special circumstances... Again - firing the injectors every 180degrees is the key, but depending on the logic used to separate the injector events, 360degree injection could work a treat (as i've got with DTA).

Jim - That Inlet manifold I drew up in Pro/E a few years ago would be pretty much ideal for what I've described... You know, maybe we should get some castings made... I reckon there are enough of us to warrant getting some proper manifold castings made...

D

some interesting thoughts there.
Dave is it easier / cheaper to get castings made in the USA than over here? Shall I have a word with Carl Ausitn to see if he can help?

Team www.sheepspeed.com Racing

Jim,

someone needs to do the math and workout if it's worth doing...
Advantages of doing a casting is you can put the throttle body in an ideal place, have tapered runners, an integral plenum, etc... But how many will want a manifold in actual fact? If we made ten, we'd be looking at £150 each - then they still need machining at a guess - and someone to knock up the moulds?

Carl is as good as anyone to ask - maybe a general post asking for casting advice?

Dave send me a copy of that drawing and i'll ask the guys who cast our work items their thoughts.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.