View Full Version : Tomcat
RAGOONEY
29-09-2009, 09:03
This looks like a nice piece of kit....If only I had the money!!:cry:
http://cgi.ebay.co.uk/rebuilt-T25-turbo-360-bearing-for-renault-5-gt-turbo_W0QQitemZ110438780053QQcmdZViewItemQQptZUK_C arsParts_Vehicles_CarParts_SM?hash=item19b6aa0c95&_trksid=p3286.c0.m14
Sounds expensive for what it is TBH, I can get a tomcat T25 new for not much more than that starting price from a turbo supplier.... plus other hybrids.
This looks like a nice piece of kit....If only I had the money!!:cry:
Why? Tomcat turbos, on the whole, are a pile of sh1t & don't give fantastic gains over an o.e T2.
Why? Tomcat turbos, on the whole, are a pile of sh1t & don't give fantastic gains over an o.e T2.
:cry: i didnt want to hear that:sad: just had one rebuilt with a 360 bearing by adam L.
i hope there at least good for more boost over the oe T2.!
UNICRONICUS
29-09-2009, 12:17
I think the 'don't give fantastic gains' is the key here Raj. It'll be more efficient/reliable at higher boost levels but the overall performance isn't vastly improved compared to an OE turbo.
I think the 'don't give fantastic gains' is the key here Raj. It'll be more efficient/reliable at higher boost levels but the overall performance isn't vastly improved compared to an OE turbo.
ok:( so what turbo would vastly improve performance then? does it not depend on what you want your car for? track,road etc? i was just after a bigger pokier turbo unit compared to the T2. i was hoping to run a Max boost pres of around 18/20psi on and off.
TrixNFlix
29-09-2009, 19:07
ok:( so what turbo would vastly improve performance then? does it not depend on what you want your car for? track,road etc? i was just after a bigger pokier turbo unit compared to the T2. i was hoping to run a Max boost pres of around 18/20psi on and off.
I thought it wouldn't matter too much dude as you were gona sell it as soon as you had completed it.:scratch::laugh::laugh::laugh::laugh:
Improve performance in what way? Road driving? Track? On the strip? Bragging rights power figures down the pub?
Unless Adam has worked his magic, I personally wouldn't want to be running a Tomcat at 20psi. I'm not saying it's not possible, but the cold wheel will be outside its happy zone. For the same reason, why d'you think so many Tomcat turbos die so often when they're hooked up to gtt's & the boost is increased?
The problem with increasing power, vnt setup aside, is that there'll come a stage when a bigger turbo is required, and with that comes lag. If it's a drag/track use turbo, that's not so bad, but on the road it'll make for a cr8p drive, imho.
I thought it wouldn't matter too much dude as you were gona sell it as soon as you had completed it.:scratch::laugh::laugh::laugh::laugh:
the thing is, it does matter! yes im selling it once its completely finished but id still like it to perform better than a std T2.
call me daft or whatever,but when i sell the 5 i want it ready to go for the new owner with no faffing about. i could put it up for sale right now as its basically finished,but i want to fit an afr gauge and also do the 2nd stage enrichment mod:scratch: need to know abit more on this though.
so...It DOES matter:cooter:
Why? Tomcat turbos, on the whole, are a pile of sh1t & don't give fantastic gains over an o.e T2.
I know they have reliability issues when moved straight from the Rover without a rebuild but I thought Tomcats turbos were decent units for power? Not used one myself but I remember Jamie using one to get 197ish BHP (backed up by traps to match) at 18-19psi
How does this unit differ from the full T25 I have from AdamL?
Improve performance in what way? Road driving? Track? On the strip? Bragging rights power figures down the pub?
Unless Adam has worked his magic, I personally wouldn't want to be running a Tomcat at 20psi. I'm not saying it's not possible, but the cold wheel will be outside its happy zone. For the same reason, why d'you think so many Tomcat turbos die so often when they're hooked up to gtt's & the boost is increased?
The problem with increasing power, vnt setup aside, is that there'll come a stage when a bigger turbo is required, and with that comes lag. If it's a drag/track use turbo, that's not so bad, but on the road it'll make for a cr8p drive, imho.
the reason i had the tomcat unit rebuilt was because i thought a t25 would give me more power and not be very laggy and suit everyday road driving. just after abit more poke,not mega power. no track or drag use although i was hoping for it to perform a little better in a straight line over the T2.
I personaly found a full T25 both a 200sx and Tomcat a fantastic upgrade over the T2, but that is just my opinion. If it's been rebuilt then I can only guess it should be OK for a while!? It's still a garret.
I could not be doing with the T2 spooling nearly all the time and found it a great compromise with good response on the road and some OK times up the stip.
Try it! You might like it!:agree::)
I know they have reliability issues when moved straight from the Rover without a rebuild but I thought Tomcats turbos were decent units for power? Not used one myself but I remember Jamie using one to get 197ish BHP (backed up by traps to match) at 18-19psi
How does this unit differ from the full T25 I have from AdamL?
What were the trap times/speeds?
Going on Jamie's figure, that's only ~20hp more than an o.e unit running a similar boost level. It's a power gain, of course, but a fair bit of hassle along the way in achieving that (sourcing one, rebuild costs, bearing upgrade, fitting issues), hence the 'not fantastic gains' comment.
Just my opinion though. I'm sure there's plenty of people out there happily running them on their gtt's...maybe ;) :D
TrixNFlix
29-09-2009, 19:37
the thing is, it does matter! yes im selling it once its completely finished but id still like it to perform better than a std T2.
call me daft or whatever,but when i sell the 5 i want it ready to go for the new owner with no faffing about. i could put it up for sale right now as its basically finished,but i want to fit an afr gauge and also do the 2nd stage enrichment mod:scratch: need to know abit more on this though.
so...It DOES matter:cooter:
Nothing wrong with that raj, messing with cars gives most of us pleasure and a hobby, so keep messing with it, and hopefully youll never finish it and still have it in 10 years.:laugh::laugh::cooter::cooter:
I personaly found a full T25 both a 200sx and Tomcat a fantastic upgrade over the T2, but that is just my opinion. If it's been rebuilt then I can only guess it should be OK for a while!? It's still a garret.
I could not be doing with the T2 spooling nearly all the time and found it a great compromise with good response on the road and some OK times up the stip.
Try it! You might like it!:agree::)
some opposing veiws here isnt there! the actual reason i went for a larger unit was due to the fact that i was getting annoyed with the T2 spooling its t1ts off on motorways.
Like all engine modifications, different parts suit different people and different styles of driving. The tomcat is a fair compromise for most people I'd say. it's going to make better power than the T2, no two ways about that. You have to be prepared to trade off some responce to get it though. I personally *hate* the T2 on the GTT, so for me it would be a great upgrade on a daily driver. Not everyone feels the same way as me though, which is fine, you just have to do whatever the hell you like best!! :cool:
Hey, it's a (rare) tech' thread with (equally rare) good discussion :D
If I was told correctly, Lloyd Bush used a Tomcat spec turbo, from TDL too I believe, to achieve the 11.9 sec pass.
What were the trap times/speeds?
Going on Jamie's figure, that's only ~20hp more than an o.e unit running a similar boost level. It's a power gain, of course, but a fair bit of hassle along the way in achieving that (sourcing one, rebuild costs, bearing upgrade, fitting issues), hence the 'not fantastic gains' comment.
103mph 18PSI Piper 285
If I was told correctly, Lloyd Bush used a Tomcat spec turbo, from TDL too I believe, to achieve the 11.9 sec pass.
Adam said he had a T25 with a .49 A/R exhaust side
Who on earth are TDL though, lol? :scratch:
the thing is, it does matter! yes im selling it once its completely finished but id still like it to perform better than a std T2.
call me daft or whatever,but when i sell the 5 i want it ready to go for the new owner with no faffing about. i could put it up for sale right now as its basically finished,but i want to fit an afr gauge and also do the 2nd stage enrichment mod:scratch: need to know abit more on this though.
so...It DOES matter:cooter:
Raj, rest assured, your turbo will handle higher boost levels without a problem and will flow beter than a T2
The only thing I don't like about Tomcats is the exhaust housing, in my opinion they're limited to a certain amount of power, and i'd cap that at 250bhp. If you're after power, it's not ideal to be running out of flow... Although the turbo is the least of your worries on a 5.
Raj, rest assured, your turbo will handle higher boost levels without a problem and will flow beter than a T2
thats what i like to hear:agree: thats all im after, nothing spectacular but just to be able to run at least 18psi @ turbo not manifold.
250hp out of a Tomcat?
well, you have to wonder... Bushy was going through at 115mph on some runs, with a tomcat style compressor and turbine. thats maybe a bit more than 240hp. ofcourse, it'll have been screaming it's nads off at that.
Didn't that blower have larger wheels fitted though?
I'm talking bogo spec Tomcat, with regards to Adam's 250hp comment.
If ya talking about a hybrid Tomcat, that's a different kettle of fish, and now we're going off on a tangent :D
well, you have to wonder... Bushy was going through at 115mph on some runs, with a tomcat style compressor and turbine. thats maybe a bit more than 240hp. ofcourse, it'll have been screaming it's nads off at that.
Ok, it was clearly running beyond it's capabilities, but it produced the goods.
What I was getting at is the housing in general, even on T28's as it's the most common.
I've never used a .49 and I probably never will.
Didn't that blower have larger wheels fitted though?
I'm talking bogo spec Tomcat, with regards to Adam's 250hp comment.
If ya talking about a hybrid Tomcat, that's a different kettle of fish, and now we're going off on a tangent :D
Mart, stock spec wheels with all the gubbins to ensure it didn't let go at 24psi.
standard tomcat with 360deg thrust, etc, he told me.
I didn't think the Tomcat wheels looked much bigger than a T2, and thought Bushy's fastest trap was ~111mph, hence querying the 250hp shpiel.
You geezas on a wind-up? :D
Rob@Backyardracing
29-09-2009, 23:14
His 11.9 was 111 or close.. but fastest trap was 115...
..but 0.49 is what you find on the quickest c1j's in the club, stuart's included. whilst it's certainly a choke at those levels you still have to balance it with responce. part of the reason why bushy's car went so well was because it was responsive. no lag in the launch or between gears at all. a T28 with 0.64 is not much use on the drag strip, far too lazy, especially when boost levels get high. It might be fine on a race track, but I wouldn't know about that..
quite a bit bigger mart, 50 trim I think ? adam might be able to confirm that.
Robby from down here has proved T2 housings can make good power. 113mph is his best I think. Mind you, it's a very rare .63 housing and that's done a 113mph. Although that's not running a 62 trim exhaust wheel like the Tomcat.
It's the inducer that's larger on the Tomcat, Mart. The exducer is still a few mm's larger than the T2, by how much I can't remember
..but 0.49 is what you find on the quickest c1j's in the club, stuart's included. whilst it's certainly a choke at those levels you still have to balance it with responce. part of the reason why bushy's car went so well was because it was responsive. no lag in the launch or between gears at all. a T28 with 0.64 is not much use on the drag strip, far too lazy, especially when boost levels get high. It might be fine on a race track, but I wouldn't know about that..
I think Turbo Ted (Robby) has run a 12.0 dead on a T2 casing. Although, he's messed about so much with his turbo I'm unsure of what spec it was when he did that.
I didn't think the Tomcat wheels looked much bigger than a T2, and thought Bushy's fastest trap was ~111mph, hence querying the 250hp shpiel.
You geezas on a wind-up? :D
Mart, i'm going on flow wise, when do you ever see cars run traps that match what the turbo will produce?
That's unless they're running past the map, which is rare, or on another component in the system like gas.
IIRC, Bu$hy was at 25psi on the Track and Road roller when they measured it at 247bhp.
Rob@Backyardracing
29-09-2009, 23:31
Slightly off topic... I agree with Scoffs comment there, my fastest run i did was with a .49, i tried the same tune on a .64 gt28r and i could never gain my 60fts or 330s back no matter what i tried... The GT28 imo is a brill unit, but just isnt responsive with a carb fed c1j...
Also to add, a local friend of mind bought an old tomcat and rebuilt it himself in his shed with no experience in that field, i set the car up to 20psi and to this date 18 months on its still going strong with a fastest run of 104mph at pod, (stock engine and cam)... I wasnt a fan of tomcats and told him it wont last but hes proved me wrong...
It's the thrust bearing that'll give way before anything else on those, Rob. Idealy you want good oil pressure higher up the revs, so the load is taken away from the boost. Must be a good engine:)
turbo ted
29-09-2009, 23:54
Robby from down here has proved T2 housings can make good power. 113mph is his best I think. Mind you, it's a very rare .63 housing and that's done a 113mph. Although that's not running a 62 trim exhaust wheel like the Tomcat.
It's the inducer that's larger on the Tomcat, Mart. The exducer is still a few mm's larger than the T2, by how much I can't remember
ran that turbo with a 0.49 housing off the t25 and could only get 109 terminals at 12.9 , changed it back to a 0.63 t2 housing ran 112-113 terminal at 12.1 :D
Thankyou, Rob :)
Proving that the T2 is as good as I was hoping.
allanr5gtt
30-09-2009, 19:40
Slightly off topic... I agree with Scoffs comment there, my fastest run i did was with a .49, i tried the same tune on a .64 gt28r and i could never gain my 60fts or 330s back no matter what i tried... The GT28 imo is a brill unit, but just isnt responsive with a carb fed c1j...
Also to add, a local friend of mind bought an old tomcat and rebuilt it himself in his shed with no experience in that field, i set the car up to 20psi and to this date 18 months on its still going strong with a fastest run of 104mph at pod, (stock engine and cam)... I wasnt a fan of tomcats and told him it wont last but hes proved me wrong...
are you saying the gt28 wasn't responsive with the .49 or just when you tried the .64?
Rob@Backyardracing
30-09-2009, 20:04
Just the .64 Allan.
allanr5gtt
30-09-2009, 20:51
Just the .64 Allan.
thanks rob it's just i have a gt28 with .49 built by td and it's not responsive what so ever. i think i will have to play with the fuel and timing.
Jimmy_GTT
28-06-2011, 10:22
I've just received my rebuilt Tomcat which I've bought from BluntyR5GTT. Thanks for that! ;)
My question is: Anybody has experience with the blow-off valve which is integrated on it? Could it be used? Or shall I better blank it off?
I've just received my rebuilt Tomcat which I've bought from BluntyR5GTT. Thanks for that! ;)
My question is: Anybody has experience with the blow-off valve which is integrated on it? Could it be used? Or shall I better blank it off?
Blank it off matey, the diaphrams tend to go over 10psi off boost, or you could get the forge unit that will fit it also forge do a blanking plate for them aswell
Jimmy_GTT
28-06-2011, 12:34
Thanks James5!
Is this the blanking plate from forge?
http://www.forgemotorsport.co.uk/content.asp?inc=product&cat=0016&product=FMBPT25
Shall I order it or it can be made from a piece of metal plate?
And which Forge BOV will fit there?
THX
Thanks James5!
Is this the blanking plate from forge?
http://www.forgemotorsport.co.uk/content.asp?inc=product&cat=0016&product=FMBPT25
Shall I order it or it can be made from a piece of metal plate?
And which Forge BOV will fit there?
THX
I can not confirm if the cosworth one is the same but stud pattern does look the same, could be worth trauling the rover forum's, 5teveL is a member on a few and maybe able to offer some advice as he has had a view Rover coupe turbo's himself over the years.
blanking plate for sale on the rovertech forum -
http://www.rovertech.net/forum/viewtopic.php?f=37&t=127097&start=0
to be honest you can alweays make one yourself out of 3mm or 4mm thick metal.
Jimmy_GTT
28-06-2011, 13:21
That would be easier than ordering such a plate to Hungary.
Or just trying to find a higher tension spring to be able to use the BOV @20psi.
That would be easier than ordering such a plate to Hungary.
Or just trying to find a higher tension spring to be able to use the BOV @20psi.
Just make yourself a plate and make sure you seal of the center hole on the D/V from the outer :agree:
You can just copy of the shape of the OE D/V and cut the shape to fit and 3 x drill holes, whack a load of decent sealant on it and tighten it down and job done:D
Jimmy_GTT
28-06-2011, 13:40
Just make yourself a plate and make sure you seal of the center hole on the D/V from the outer :agree:
You can just copy of the shape of the OE D/V and cut the shape to fit and 3 x drill holes, whack a load of decent sealant on it and tighten it down and job done:D
Will try to make one during the weekend.
Thanks again.
Cossie runs the same IIRC.
You can get a piston type BOV that bolts onto the turbo, better than the diaphram ones ;)
I think Collins made them.
Jimmy_GTT
14-07-2011, 06:29
Can someone please tell me what is the oil feed screw thread size on a tomcat?
This is the screw between the central housing and the oil feed line.
I've read that on most T2-T25 it is M11x1.0 but it is definitely not. Maybe M11x1.25 if it is metric at all?
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