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GTi NA Power upgrade

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Right I have been thinking about a power upgrade for some time now and after thoughts of a 1.8T, turbocharging my Gti engine and attempting to get a supercharger I have settled on my old favourite (and something I have done before) and started looking at normally aspirated power.

I want `190-210bhp` from the Gti engine by whatever means possible. Thinking major head work and cams, throttle bodies, management and any other tricks possible.

I heard rumours of a 205bhp Lupo Gti engine that was normally aspirated but cant remember the source of this. Can anyone help as come summer my warranty will be out and I want some power.

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It was a member here.

Ah!! forgotten the name!

Hang on he posted in my TBs thread..

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Ok found him

Dogwood

Profile

Think it was 210bhp from a race spec, GTi engine.

Read somewhere that you may need a new head for serious tuneing although Im sure Twisty can conferm that is true?

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Yeah - this came from a VW Cup type bloke someone else posted about (baj maybe??) - GTI bottom end, new top end, but not sure what yet!

The problem with TB's is the management unit, what alternative can you use, unless you go and replace it with fully custom race one

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I think I remember also reading your only looking at £300 for the new ECU.

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oh really! thats pretty good..... would be good to find someone who would do this for me though (head, cams, tb's, ecu).... must be a market for it

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Speak to Badger Bill Tim :wink:

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I did, a couple of weeks before the rolling road day. He'd prefer the engine preparation done first (cams, headwork), so he is left with the fuelling

He could've got a third party to do the prep and charged me a crap load

Hopefully he'll be along to post it first hand

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If it was using a std bottom end it would be brilliant as the whole top end could be swapped straight over with no need to unbolt and remove engine and gearbox. I have already been told the Gti motor can be let rev to 1000rpm over the standard limiter so more revs with tb's would not be a problem on the std bottom end.

I am prepared to live with a wild head and cams even if it affects town drivability as most (95%) of my miles are open road driving. Maybe even use 8 injectors with tb's, I dont really mind as long as its around 200bhp, noisy and fun.

Also tb' would be much cleaner and tidier than the std inlet set up, which releases space in the engine bay and will try to eliminate some of the std Gti's common heat soak problem due to the cluttered engine bay.

Dogwood, you got any info for me here...like that 200bhp engine parts to sell me? biggrin.gif style="vertical-align:middle" emoid=":D" border="0" alt="biggrin.gif" />

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To save him typing it all again biggrin.gif style="vertical-align:middle" emoid=":D" border="0" alt="biggrin.gif" />

The questions I asked were (basically): is the 256 Shrick cam extreme enough profile and should I get the crank and rods replaced as a precaution

I must resist asking more, I must resist

QUOTE(Dogwood)
The real killer on the Loop is the induction. Throttle bodies are the big gain, but they are costly and may need some mods to the shell, plumbing and wiring to install which I can't bring myself to do on a 2 year old car. There is 170bhp without bodies for sure. The cars that run in the DTC in Germany make 180bhp. They run to pretty much Group A regs, which is: standard crank and rods, pistons can be changed. Flywheel can be modified but must retain origional diameter.  

Head can be flowed but valve sizes must be standard. Inlet manifold is standard but they run an airbox with a remote induction kit type filter earlier in the system. Exhaust manifold is `4-2`-1 with long primaries. System is pretty unrestrictive as you'd expect and they use a HJS race Cat. Cams are obviously different, but I don't know what they are. I'm pretty sure that they still run with the standard roller rocker set up though.  

So, what i'm thinking is:-  

Leave the bottom end alone. The crank and rods are both solid for 8000revs. The pistons are light enough and the CR is already quite high at 11.5:1. Get the flywheel lightened so the whole lot has less work to do though. Get the head done off someone good (I know someone but he is slow), `4-2`-1 manifold, freeflow cat and system (Again I know a place up here). Use a BMC but make sure it is well fed (ducted from the drivers bottom side grille). The only question mark is the cams. I don't think 256 is enough either, having said that, I don't know the relationship between cam profile and the variable inlet. I need to do a bit of digging, maybe Bill can help here too as he is an agent for Schrick and Cat Cams. I think with the right cams, there should be at least 170bhp at about 7500revs, providing we can find someone to sort the fuelling/ignition.

I didn't know whether it was my place to post that or not, not being my info, but if we're not careful his inbox will be full of private messages asking the same questions

Sort of disclaimer: if you take that info and use it, then your engine breaks you can't blame him. Though hearing about the specs of his own engine I have no reason to disbeleive it

I can't hyperlink it but go to www.`uk-polos`.net and check the polo gti section for poussou "adjutable camshaft gears thread" Anyone got any opinions on that? I've `e-mailed` Shrick and `VW-Racing` but not had an answer about whether the 256 Schrick is enough profile for what I want

Basically it's going to cost me £2000 for 40bhp and then at least another £3000 for another 10 or 15bhp. Revving past 8000 is going to be £££ as always

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Interestingly the bloke from `uk-polo`'s has had his car rr'd and remapped and is pushing out 127 bhp @ the wheels and 148nm torque @ the wheels.

link to thread

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200bhp can be done from the GTI motor. The works Polo kit cars made about 215 - 220bhp. The only way to get it though is revs. You need 9000. This is big bucks. For all parts and machining bank on £8000. Thats getting alot of parts made specially. The stuff is available off the shelf in Germany, but add at least 25%, plus they aren't keen on selling you it as they'd prefer to build you an engine for £15000. Then labour to build it, say £10000 all in at best.

You can use the factory crank, but lightened. Steel rods, forged pistons, steel flywheel, race clutch. These parts aren't really a problem.

The problem with the GTI head is the valvetrain. The setup is only good for about 8000 revs for high use. Count on maybe 7700 for the valve springs though. VWM eventually found a fix but I don't know what and it was expensive. The AFH (Sport) head is a different kettle of worms. There is alot of stuff available off the shelf. A good way to go is the Schrick Group H kit. 292 cams, springs, valves, caps. Arrow do solid followers off the shelf. Vernier pulleys are easy from Germany. This all needs ALOT of machining.

Inlet manifolds are from Germany, Jenvey throttle bodies, airbox ducted to front of car, DTA or similar management, proper manifold and system.

Bobs you uncle 200 and a bit horses!

However, bank on a freshen up every 5000 miles max to be safe rather than sorry.

You'll then need to shorten the gearing as the car will be geared for over 180mph. The GTI box is totally different to the rest and I honestly don't know what is available. Deffo nothing in England.

Hope this helps a bit.

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QUOTE(twisty `b-road`)
I did, a couple of weeks before the rolling road day.  He'd prefer the engine preparation done first (cams, headwork), so he is left with the fuelling

He could've got a third party to do the prep and charged me a crap load

Hopefully he'll be along to post it first hand

The conversation was the engine must be modified to breath better to remotely get close to the power goals you're after, but also reliability when pushing that hard and drivability is likely to be compromised.

When the engine "wants" to breath more then t'bodies, mapping etc will nett you more bang for buck, or you have to remap as its developed with the costs associated with that.

Dogwood is by far the best guy to comment on the engine spec and costs likely. T'bodies, mappable ecu etc... yea I can do them, but I dont build engines.

regards

bill

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Will soon see! lol

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200bhp can be done from the GTI motor. The works Polo kit cars made about 215 - 220bhp. The only way to get it though is revs. You need 9000. This is big bucks. For all parts and machining bank on £8000. Thats getting alot of parts made specially. The stuff is available off the shelf in Germany, but add at least 25%, plus they aren't keen on selling you it as they'd prefer to build you an engine for £15000. Then labour to build it, say £10000 all in at best.

For those sort of prices you'd be better of looking at a 1.8t conversion

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For those sort of prices you'd be better of looking at a 1.8t conversion

<{POST_SNAPBACK}>

Well, I prefer NA engines reving to 9K so I prefer to spend money in this way.

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so, if you wanted to get a bit more power than you would from just an exhaust and a filter...but keep it everyday drivable whats next?

a little porting and polishing of the inlets/outlets?

for those that have fitted them, whats a gti like on t/b's?

cheers

chris

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I've got what I think is the fastest naturally aspirated Lupo out there. Currently I've limited the power by limiting the revs.

I have rolling road tested it at 185bhp @ 7500 rpm. More power is available, it's just a matter of how reliable it would be if I let it have another 1000 revs. We saw over 190 bhp when we let it go up to 8000.

As ever, big power doesn't come cheap so be prepared for frequent visits to the bank manager!

Basically you need to start with the 1400 engine and head. The 1600 head has limitations. I know. as I tried that first. Even VW Motorsport in Germany had trouble getting the 1.6 valve gear to be reliable. They did offer to supply me a prepared engine and head but only on the basis the I leased it and returned it to them whenever there was a problem. Expensive and a big hassle.

With a change of crank and rods from the 1600 to the 1400 and some new pistons you get 1600 or a little more with an overbore.

It's not too tricky but there are some bits which I ended up getting fabricated like the exhaust and inlet manifold. Apart from that it was off the shelf.

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Im confused?

The 1400 block is not as long as the 1600, so wouldnt the pistons hit the head useing a 1600 crank and rods?

Wouldnt custom rods be needed?

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I heard roumers about a kit, giving 225 in the GTi..

from germany, according to the source it would set you back some 5500€.

Have 0 links, could that be the cup kit?

Or has someone seen anything like that?

How much can we push the std ecu?

The next step is map'd injection?

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