My car runs a t4 turbo at the moment and its fine, Good power delivery, not too laggy and works quite well But it is pretty much too its limits. The engine and pretty much everything else is uprated for more power and ive been thinking about going to an externally gated gt35 and i wondered if any one had any comparrisons between the two turbos i.e. would the gt35 be hurrendously laggy compared to the t4 and would it still be as nice to drive from day to day

Thanks in advance and your opinions are most appreciated

Steve

 

Why do you need more than 500bhp in a day to day road Cossie !?!?!?

What gearbox and diffs you running matey?

 

personally i'd stick with the T4...maybe have it modded for a bit more power...maybe even go external wastgate on it

GT35 is huge though really...i'd have thought one of the larger GT30 variants would have been more suited...unless you're just maddddddd

will you be out in it on Tuesday night at the BCRSOC meet? if so i'll see you there

 

Glebe straight cut gearbox, and the rear diff will soon be broms jag diff and full rear beam set up

And why need more power?? dont really know just thinking through a few options

Steve

 

Yes mate, hope to be

 

GT35 is quite a vague description, so lag etc is going to vary depending on the trim of the blades and the AR of the housings etc

But basically a GT35R will not be any laggier than a T4 as a general rule of thumb.


As above though, a GT30 woudl give you the power you have now but with more punch delivering it

 

Why oh why do people bang on about lag, lags only an issue when you're too lazy to change gear's!

Anyway this new T4 Euans testing might cure some of the response issues

 

What a load of bollocks

 

Lag is an issue for me as i dont have std ratios in my gearbox
At 8000rpm mine does 70mph in 1st gear and 100mph in 2nd and only 170mph in 5th

 

Ill try and get some more info as ive been offered a deal on one with my T4

 

Oh hear we go!

So if i lauch at 5k, to the red line, change up to second - where's the lag?

I i sit there cruising in 5th at 2k then floor it, course they'll be lag FFS. So changing down the box will get me back on song will it not?

 

Franco please come back when you have any relevant experience of any Turbo bigger than the one my mum has on her food mixer. Until then kindly STFU.

Thanks

 

If you are doing 2k in 5th, change down and then floor it, then where the lag is, is the time it then takes the turbo to spool up at 4000rpm in 3rd (or whatever the actual rpm works out at on your particular box)

you seem to be somewhat confused between the term "lag" and "boost threshold"

Boost threshold is the places within the rev range the engine is capable of spooling the turbo, lag is how long it takes to do so once you are in that threshold.

 

hey i only go with Martin tells me Lee

I ship shit across the world, not build engines!

 

So much more sensible a reply than even having a go to try and explain it like I did, I really shouldnt bother!

 

Lag, boost threshold...........yadda yadda yadda!

 

Its like trying to explain calculus to some elephants

 

Who you calling an elephant chubby!

 

 

Anyways now we cleared that up, surely if the gear change keeps you in the Boost threshold the lag isn't going to be THAT noticeable on a well specced engine.
(PS Fuck off Lee!! My mums food mixer is massive!).

PS i hear loads of people have/are downgrading from a 35 to a 30, so there's obviously something amiss with them.

 

Unless you just drive on long stright lines and not into fun stuff, you fucking well will care about lag and boost threshold on a T4/GT35 franco, trust me!

 

Furry muff! They all feel fucking fast to me anyway!

 

Well specced as in not having a turbo thats too big and laggy you mean?


Yes they are laggier than a 30, and with a 30 capable of going up to the best part of 600bhp, its not something you need to compromise on.

Just like people going for 350bhp dont tend to use a T4, because its laggier than a T34

 

Steve,
You certainly won't be able to have the ALS on the GT35 like you have on the Mar-M shafted T4 you currently have. If you want more power, why not upgrade your T4 that you have with the larger compressor (this is what I did and tested the turbos back to back ), which will shift 4lb of air more than the one you have at the moment. Good for 550+bhp with a correctly specced engine .

 

he's just being a girl, not even driven the car properly since he's had it mapped is bizzare doing 100MPH in 2nd though

Just keep your cash in your pocket and enjoy the car for once mate, Once the rear beam is sorted and you can launch it properly 0-100's and 1/4's are going to be seriously seriously mental

 

Mmmm interesting.. Whats involved in changing the compressor?? and roughly how much to get it done??

Steve

 

Ł300 inc return delivery. You would need to at least send the core and the compressor housing (or the complete turbo if you would prefer). The compressor housing is machined out and different wheel is fitted. It needs very good cams and head work to flow the air though!

 

If your Tuner is able to correctly Spec your engine to get a GT35 working without surge its on a different planet to the T4. My 630bhp conversion was much more drivable & with less lag than the T4 inspired 500bhp engine. It was the ultimate squirt & go machine for the road.
Rod

 

So does that SORT of make my theory correct then that a well specced engine wont suffer?

Because according to all the other gimps, i'm an elephant!

My dad reckons you only learn from asking stoopid questions!

 

I didnt see Rod saying his car had NO lag, merely that it was better than what other tuners did and so made a fantastic compromise between out and out power, and power delivery.

Mark still obeys the laws of physics, but he does seem to do a good job of bending them a little sometimes

 

People seem to underestimate the GT30.

I'm running a GT30 hybrid core in a standard bolt on fit (yes you heard lol) housing on my Sccob currently. 1bar at 2700-2800rpm, full boost (1.5bar) at 3000rpm. 480bhp @ Fly at only 1.38bar boost (was on a hub dyno the other day and got 395 ATW) due to not having a strong enough actuator. This core will run 2bar all day, go figure what it would be capable of at this boost level (it made just under 400bhp at 1bar).

I am about to bang a different core in (but still a GT30 hybrid) and wind the boost up. The aim is to have the same response as present and make about 550bhp on pump fuel...... this will still be using a GT30 type core.

Plenty of life in a quick response GT30 Hybrid turbo me thinks.

 

Ste, why not speak to Karl about how you want the car to drive and get him to supply the exact spec turbo for your engine.

Surely he will be adjusting the map to suit the new turbo?

What does he suggest?

 

The car aint been to Karls its been to Stu's and i only started this thread to get some ideas The other option is of course a good shot of nitrous but before anything happens i would discuss it fully with Stu first

The car is awesome as it is and i need to learn the car as it is first and just looking at options for the near future.

 

I cant believe you want to change the turbo spec already.
I thought that 37 psi on a T4 with ALS and LC would of kept you
amused longer than a week.

Looks like were having another trip to Blackpool then mate.

 

Ahh thats why you think i'm being a complete div, of course i understand you'll ALWAYS have some kind of lag while the turbo spools up, i was trying to get at all the people who walk about moaning they're cars 'WELL LAGGY.........'

Change down a gear then!

Obviously to us mere mortals, we'd probably never notice a issue with a well specced engine

When you talk, do you sometimes catch a whiff of some kind of shitty smell appearing to be located just above your top lip? Bit like someones wiped they're finger up the crack of their arse and wiped it on your top lip?

 

That will be a week tomorrow And blackpool on a thursday night is awesome

 

I can imagine Stu and Comedy Dans faces as they think to themselves.............Oh no not these Brummie cooonts again.

 

would be interesting to be able to drive a few different cars with differenty specced engines and turbos to see how thy compare.

Most people on here can only really comment on their own car.

One thing I can remember is Mark telling me that he can make a GT30 respond like a t34 and make a GT35 respond like a T4.

he also said that a GT35 is good for about 100 bhp more than a T4.

 

Good info mate, cheers Thats what im looking for really the car i have now but with more power

 

[quote="rapidcossie"]would be interesting to be able to drive a few different cars with differenty specced engines and turbos to see how thy compare.

Most people on here can only really comment on their own car.

quote]

You can drive mine if i can drive yours.