Why is it easier to turbo a GR than GPX???

FtoSam · Post by **FtoSam** » Wed Oct 11, 2006 11:24 am

Okay after having a quick read over redlines GR turbo thread, a lot of conversation regarded the GR as being easier to turbo than the GPX... Why is this so? I understand MIVEC would have some things to say about it but wouldnt turbo+MIVEC kick arse??? surely just reprogramming the mivec settings would compensate for the turbo's effect.
I know there should be a good reason for no one turbo'ing gpx's...
anyone care to explain?

FTO338 · Post by **FTO338** » Wed Oct 11, 2006 11:45 am

Compression ratio on the GPX is higher which is not ideal for turbo, but in order to utilize the "MIVEC CAM" the ratio needs to be high.

Yes in theory, you can just adjust the setting of the MIVEC point to suit, but I yet to see someone who actually had done it properly.

So far Iâ€™ve seen turbo GPX are either left in high CAM setting, which mean not much low end, or using a stand alone ECU to deal with the problem, but end up with cold start problem and can only run on low psi. Which end up around 130-140kwatw.

You can leave it at very low boost and with the standard ecu and mivec setting, but I don't know how long the engine will going to last. The last person who tried had blown his engine within 3mths.

EURO · Post by **EURO** » Wed Oct 11, 2006 11:53 am

There was a good article on one of the irish websites about turboing a gpx wasnt there? Talks about some of the issues they had.

FtoSam · Post by **FtoSam** » Wed Oct 11, 2006 12:29 pm

unlucky.... what are my options for big power N/A??

FTO338 · Post by **FTO338** » Wed Oct 11, 2006 12:36 pm

Samson wrote:unlucky.... what are my options for big power N/A??

Need a deep pocket or a good size bank account and then talk to Dav from RPW. Or get yourself a Honda, where parts are much cheaper.

AJCFTO06 · Post by **AJCFTO06** » Wed Oct 11, 2006 12:42 pm

would you receive more power from a "big power N/A gpx" or a turbo GR??

Liquidity · Post by **Liquidity** » Wed Oct 11, 2006 2:29 pm

Either one could be worked to ridiculous levels. Its all about money.

bang for buck, best option would be neither, i imagine. best option would probably be a 6a13tt conversion, or 4g63 conversion. Would probably end up costing about the same as a full on worked n/a 6a12 mivec, or turbo worked 6a12.

JahjaMan · Post by **JahjaMan** » Wed Oct 11, 2006 4:58 pm

hmm, im looking through RPW's catalogue and i cant seem to find anything on the 6A13

can someone give me a few pointers on this engine?

AJCFTO06 · Post by **AJCFTO06** » Wed Oct 11, 2006 8:08 pm

Liquidity wrote:Either one could be worked to ridiculous levels. Its all about money.

bang for buck, best option would be neither, i imagine. best option would probably be a 6a13tt conversion, or 4g63 conversion. Would probably end up costing about the same as a full on worked n/a 6a12 mivec, or turbo worked 6a12.

so your saying i should buy a cheap GR

and get a 6a13tt conversion? and it wouldn't make any difference than the GPX? just cheaper.

Hobbsie · Post by **Hobbsie** » Wed Oct 11, 2006 8:35 pm

yes the only real difference between gpx and gr is the mivec engine and if youre replacing the engine it doesnt matter anyway..

there are slight differences in suspension and gadgets and stuff too but nothing important

FTO338 · Post by **FTO338** » Wed Oct 11, 2006 9:54 pm

The brakes are also smaller in the GR.

jonowong · Post by **jonowong** » Wed Oct 11, 2006 11:48 pm

it is always easy to turbo a car without variable valve timing... if they worked together well wouldnt all the high performance cars have VVT? like the GTRs? and dont mention the EVO9 having mivec like the FTO because the EVO9 mivec is for fuel saving not for power

the evo9 mivec and the fto mivec work totally different

khunjeng · Post by **khunjeng** » Thu Oct 12, 2006 12:05 am

jonowong wrote:it is always easy to turbo a car without variable valve timing... if they worked together well wouldnt all the high performance cars have VVT? like the GTRs? and dont mention the EVO9 having mivec like the FTO because the EVO9 mivec is for fuel saving not for power

the evo9 mivec and the fto mivec work totally different

the GTR and GTST have VCT..called NVCS...its not the same. NVCS is not to be confused with VTECH which alters lift and duration high in the rev range to give higher peak power. Nissans system uses cam phasing to increase low to mid end engine torque.

jonowong · Post by **jonowong** » Thu Oct 12, 2006 12:20 am

ok my bad

FTO338 · Post by **FTO338** » Thu Oct 12, 2006 12:27 am

Lots of cars these days have some sort of Variable Valve Timing and thats including turbos, but they are design for fuel economy and not as aggressive as the original Mivec or even some early VTEC YO!!!!! (not iVtec).

G_A_V · Post by **G_A_V** » Thu Oct 12, 2006 11:00 pm

The Air Intake sensor is different on the two cars, the gr one is external (before turbo) the mivec is on the throttle body (after the turbo).
Although a good tuner should be able to get around the hurdles of turboing the mivec.
Also both engines have the same compression ratio 10:1 only the 4cyl has a lower compression ratio of 9.5:1

Nacho · Post by **Nacho** » Fri Oct 13, 2006 12:22 am

jonowong wrote:and dont mention the EVO9 having mivec like the FTO because the EVO9 mivec is for fuel saving not for power

I thought the main purpose of the MIVEC heads on the EVO IX were to increase low end power?

Liquidity · Post by **Liquidity** » Fri Oct 13, 2006 1:24 am

supra's have vvt-i (some of em

)

FTO-101 · Post by **FTO-101** » Sat Oct 14, 2006 12:50 am

my mate had a VTEC YO!!!!! honda integra that he turbo charged it gave him so much trouble that in the end he sold it bought a non-VTEC YO!!!!! integra and turbo charged that. it was easier and actually went a lot harder so turbo a Gr not a gpx

payaya · Post by **payaya** » Sat Oct 14, 2006 9:59 pm

FTO338 wrote:Lots of cars these days have some sort of Variable Valve Timing and thats including turbos, but they are design for fuel economy and not as aggressive as the original Mivec or even some early VTEC YO!!!!! (not iVtec).

The VTEC YO!!!!! and Mivec is bascially an on/off switch. newer cars have a more linear system.