Jump to content
The mkiv Supra Owners Club

cams and cam gear question help please


MONKEYmark

Recommended Posts

hi i am getting my hks cams and cam gears fitted next week to my j spec auto on thursday day.then will be going on rollers to see what power i am running.

thing is i wanted them doing intime for the 26th of may when i will be racing on york dragstrip

 

someone has put doughts in my head saying that i will have to run the cams in

i dont want to risk anything breaking.does anyone have them fitted or know if this is right

 

i will be getting them fitted at dragon autosport on 23rd may

 

is that too soon to be going to dragstrip

i will be driving from essex to cleethorpes then onto leeds then from leeds to york dragstrip say about 300 miles driving. would that seem ok

 

 

hope i am worrying for nothing. if i have to ride them in will give the dragracing a miss

 

thanks for any help or info

Link to comment
Share on other sites

hi gavin someone put dought in my head about it

i thought i would ask the experts.i never even thought about it

was going to just go to race a couple of days later.

 

dragon autosports will know what they doing with the rolling road. when they test car out on rolling road do they put it in drive then floor it till it hits rev limmiter

 

dont know how it works on an auto

 

just want to get it on rollers to see what power and if fueling is ok

 

 

is there anything else i need to know

 

not got a boost controller

 

just a gauge and it seems to hit 1.1 to 1.2 bar

but on rollers will it keep boosting till it blows something?

 

thanks

Link to comment
Share on other sites

Guest Martin F
Originally posted by GavinL

 

BTW - If anythings likely too break it will be on the dyno not the drag strip.

 

Agreed, seeing your car on the rollers is a bit nerve racking and nearly all the stress is on the engine.

Link to comment
Share on other sites

when they test car out on rolling road do they put it in drive then floor it till it hits rev limmiter

 

dont know how it works on an auto [/b]

 

 

 

I'd have thought the best way would be to stick it in MANU mode, select D and floor it, otherwise it will kick down when you floor it and possible change gear mid power run!?

 

:baa:

Link to comment
Share on other sites

Originally posted by Martin F

Not sure if this is the best way, but worth a read :-

 

http://www.mkiv.com/techarticles/how_to_dyno/index.html

 

Just make sure all traction control systems are off :D

thanks martin i will ask at garage about rolling road and how to do it the best way.

 

i thought a dyno was when the engine comes out to test the power more accurate?

 

 

anyone have an idea if the cams need to be run in

i just want to find out if i can race or not

 

thanks

Link to comment
Share on other sites

It has been a while, but high performance cams I have fitted in the past, have come with special oil which you cover the running gear in. Then you just run them in at set revs for a specified time (minutes) under no load. Job done. Then its away you go. Form what I remember the important thing was to get to highish revs quite quickly. I will have a hunt around in the garage I may still have the instructions somewhere.

 

I am not sure about the procedure on the Supra though.

 

Just reread your origianl post, you are having them fitted so, it should all be done.

Link to comment
Share on other sites

Originally posted by Terminator

It has been a while, but high performance cams I have fitted in the past, have come with special oil which you cover the running gear in. Then you just run them in at set revs for a specified time (minutes) under no load. Job done. Then its away you go. Form what I remember the important thing was to get to highish revs quite quickly. I will have a hunt around in the garage I may still have the instructions somewhere.

 

I am not sure about the procedure on the Supra though.

 

Just reread your origianl post, you are having them fitted so, it should all be done.

so if i am getting them fitted and timed up and say a steady 200+ mile drive should bed them in and will it be safe to go to dragstrip say 2 or 3 days later.have never bought cams before the supra is the first car i have bought bits for and first car to be tuned up.

must say hks and blitz stuff seem solid and well made.

 

thanks all for your time to reply

 

just want to be clear

 

last time at york i managed to get 15 runs in my supra

the one i am going to on 26th may will be busy so i will be lucky if i get 8 runs in

Link to comment
Share on other sites

Originally posted by Terminator

It has been a while, but high performance cams I have fitted in the past, have come with special oil which you cover the running gear in. Then you just run them in at set revs for a specified time (minutes) under no load. Job done. Then its away you go. Form what I remember the important thing was to get to highish revs quite quickly. I will have a hunt around in the garage I may still have the instructions somewhere.

 

I am not sure about the procedure on the Supra though.

 

Just reread your origianl post, you are having them fitted so, it should all be done.

 

Phil..

 

The HKS cams don't require shims, just drop straight in. Does this have any bearing on the matter?

Link to comment
Share on other sites

Originally posted by Wez

Cheers for the info :)

 

What sort of gains should be expected on a J-Spec with nur spec exhaust, induction kit and and running at 1.2bar.

 

Just curious.

 

:stupid:

 

I reckon about 30-40 bhp plus increase in torque on a J spec. Not the most economical of mods BHP/£ wise.

Link to comment
Share on other sites

I would say more like 20 bhp . . . from speaking to Chris Wilson last week, the stock cams are pretty well optimised for the stock turbos. When you fit a bigger turbo with much less restrictive exhaust housing (ie not hybrids either, something like a big single), uprated cams would then be useful to take advantage of it and optimise gas flow through the head.

 

That's my understanding of what he was saying anyway, I'm sure someone will let me know if I have it wrong :conf: :rolleyes:

 

Does anyone have some before-and-after dynos from when they've put cams in? Some people seem to think they're great, others are disappointed . . .

Link to comment
Share on other sites

Adam, don't forget on the J-spec the Cams are a source of restriction put in by Toyota to help the engine lower its power figures down to 280bhp. When your talking about 1.2 bar they could be good for the 30-40 hp gav mentions as up to a point they are still providing restriction....the question is at what point are they not the restriction...can anybody pinpoint that?

Link to comment
Share on other sites

Originally posted by Alex Holdroyd

Adam, don't forget on the J-spec the Cams are a source of restriction put in by Toyota to help the engine lower its power figures down to 280bhp. When your talking about 1.2 bar they could be good for the 30-40 hp gav mentions as up to a point they are still providing restriction....the question is at what point are they not the restriction...can anybody pinpoint that?

 

Sorry, have to disagree there! The cam lift and timing is matched to the turbo housing sizes and as such adding more (for example) exhaust duration to a car with stock J-Spec turbos won't show much benefit, as the ports are "seeing" a restriction, and you may even get worse performance due to poorer scavenging, even flow reversal. Add bigger turbos, and i don't mean hybrids which nearly always have stock exhaust housing sizes, as changing the exhaust housing is a LOT more expensive than changing compressor housing, or at best clipped turbine blades, then you can make a wilder cam profile in the exhaust work a lot better. In other words the cams weren't chosen to restrict performance, which would also adversely affect BMEP, and hence economy, but to work WITH the turbo sizings chosen.

 

All in my opinion of course, I can only guess the designers intent.

Link to comment
Share on other sites

Originally posted by Alex Holdroyd

Grrr...I stand corrected... :(

 

So to recap..don't mod anything unless your going to mod everything in one foul swoop!

 

 

 

So find 20k give the car to Chris and let him at it for a couple of weeks/months!

 

Foul :-) (Fell) I think I prefer foul though!

 

I do like the sound of your later advice, very good indeed

Link to comment
Share on other sites

This may be a silly question but does changing the cams in theory give you a higher rev capability.

 

What is the standard rev limit on a J-Spec and how can you increase it safely, is it the same for a UK Spec?

 

 

:stupid:

Link to comment
Share on other sites

Wahey! I got it right! :)

 

Anyway . . .rev limiters (let's see if I'm on a roll here!)

 

The rev limit would be unaffected by the cam profile. It's a function of how strong and well balanced the engines internals are. If you wanted to raise the limit you would have to uprate the entire valve train, and probably the reciprocating bottom end parts like the conrods, maybe the crank? Not sure.

 

However, if you fit a really wild cam you may shift the powerband so far upwards that it's beyond the stock rev limit, meaning you would then be forced to uprate everything to get any benefit. Is that what you are thinking of?

Link to comment
Share on other sites

Yeah Adam cheers, good info.

 

Have you seen the replacement TRD rev counter, goes upto 10 and replaces the stock counter.

 

Not alot of use on stock motor i guess, but still looks pretty funky :)

 

TDI will upgrade cams and pulleys etc for about £750 plus fitting and VAT is that a good price? how easy is it to do as they say it only takes 4 hours.

 

:stupid:

Link to comment
Share on other sites

This was covered in depth recently have a look for a rev limit or engine internals in the search function.

 

According to the engineers amongst us its hard to get more revs out of the 2JZ as its a long stroke engine...hence why its 3L and a similar engine in the Skyline (RB26DETT) is 2.6L short stroke we get more torque and crusing ability they get manic revs!

 

By lightening all the internals and the drive train I think 7,500rpm would still be as high as you want to go...500rpm up on stock.

 

Having said that PHR in America sell engines preconfigured for a "safe" 9,000 rpm but this would require frequent rebuilds.

 

For reliabilities sake I'd stick to the current rev limit until you have an engine bay full of other mods... much to my own personal dissapointment

 

In answer to your original question using better cams won't allow you to raise the rev limit...and you'd need an Aftermarket ECU to do that anyway.

 

PS have a look at JUN cams they are the *ollocks

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.