power at high revs

[Slim]

Hi guys.

I have a t28 and a 285 cam. My power seems to drop off at 6k, which i thought a 285 cam should still have power at.

Can anyone tell me why? or what it could be? I dont think its timing (im no expert) but the engine was built by a quite reputable person on here a while back. Its always been like this,, js thought a big turbo with that cam should have had a bit more power there.

p.s have recently changed fuel filter and carb is also tuned for 20psi.

[Brigsy]

It all depends on how the cam is timed up?

[TNT ANDY]

I have a similar issue, I also have the Piper285 in there on standard timing. it is on my list of things to do.

[Slim]

im not sure how the cam is timed up,,, i think its timed on standard :cartman:

Colin AKA the Master built it a while back, so il have to ask him.

what/how should it be timed?

[Eugein Offord]

Yo... a lot of members think the piper 285 is great but i'd say it is better cam than the original... its a worthy upgrade and a straight forward one but the one to impress is the ever happy Kent cam RT200...............rumbles way past 7000 rpm.....

[Brigsy]

Piper 285 will make more power dialled in with a bit of retard will make more power and drive a lot better in a road car ;)

[Slim]

will it make the turbo more laggy tho?? more power up top?

[Slim]

can anyone tell me more details on what happens if I retart the timing a bit pls??

[James5]

can anyone tell me more details on what happens if I retart the timing a bit pls??

Retarding the cam timing, increases the power curve - the power curve will start later at a higher rpm

[Slim]

Retarding the cam timing, increases the power curve - the power curve will start later at a higher rpm


does this mean my turbo will start to boost later then?? and how will it make a better road car??

[Eugein Offord]

the improved flow of gases with a higher cam will reduce lag...............the rt 200 would pull harder from 4000 rpm way past 7000 rpm it works well and would idle really nice..... up and down ...

[Slim]

the improved flow of gases with a higher cam will reduce lag...............

:scratch: are you saying if you retard the cam timing the turbo will kick in earlier? are you sure?

[Eugein Offord]

:scratch: are you saying if you retard the cam timing the turbo will kick in earlier? are you sure?

i'm talking about the RT.....which wont need retarding......................but as you have a 285 i shouldnt bang on about another profile....:eek::cry::cry:

[Slim]

ye i js wana know if i retard the 285 will the turbo kick in later,, as i really dont want it to be any more laggy than it is! currently full boost around 4.3k (20psi)

[Eugein Offord]

i was a passenger in a gt with a set up like yours with a t28 and a retarded 285.... and it went well but the lag was poor.......... i think it would reach full boost at 5000 rpm but that was a 28 psi........and it did pull well i think it was dyno'ed at 240'ish BHP...

if it was me and it ain't... id run the T28 up to 30psi depending on your cooler.......... if your happy with the power at 20 psi but want a lot less lag id go for a T25 and turn if up to at least 25 or 30 psi....but it depends o the intercooler/ waterinjection/carb setup to get the best but a T3 at 20 seems a bit of a waste to me...........

[Slim]

cool thanks. Ye i was planning on running around 24 ish..

[Brigsy]

Retarding my piper 285 made hardly no difference to lag. Just get a few degrees dialled in and enjoy.

[Slim]

Retarding my piper 285 made hardly no difference to lag. Just get a few degrees dialled in and enjoy.

but did it rev longer?? can you give me a kind of summary overall pls!! lol

maybe before and after?,,worth doing or not?

[Brigsy]

Yes, the powerband is higher up the rev range. Get a dti on yours and check what it's timed up at?

Them rt200's aren't nowt flash eug, when I had a similar profile cam fitted in my engine it made all the right noises but lag was terrible and power wise it didn't deliver the goods. Sounded nice on idle though.

[Slim]

dti? not sure what that means.. but il find out and will do that and get back to you lol

[tiff_lee]

http://www.ebay.co.uk/itm/0-10-MM-DIAL-GAUGE-DTI-MAGNETIC-BASE-/300645608995?pt=UK_Measuring_Tools_Levels&hash=item45ffdfee23#ht_1382wt_1163

Edit: DTI - Dial Test Indicator

[Scoff]

The RT200 / RT150 / BP300 are a bit crap at dealing with high boost. They should make a nice cam for a track car at low boost. Way too much lift @ TDC to make power at high boost. As the brigster says, BP285 at the "right" timing is much better :)

[tubbyG]

http://www.ebay.co.uk/itm/0-10-MM-DIAL-GAUGE-DTI-MAGNETIC-BASE-/300645608995?pt=UK_Measuring_Tools_Levels&hash=item45ffdfee23#ht_1382wt_1163

Edit: DTI - Dial Test Indicator


:laugh: i just got that exact one delivered this morning :laugh:

[GTphil]

I have the piper 285 with retarded timing it's the 112d one and it's at 116d with a t28 running 24psi i'm at full boost by 4.6k rpm and pulls very strong right upto 7.5k and probably beyond but my balls aint big enough!

Mine seems to idle quite nicely a touch lumpy but nothing to complain about:)

It did increase the lag but only by a very small amount and now it seems to want to rev a bit more it goes up to 7.5k as oppose to 7k that i reved to before so for a little more lag it revs happy (if you can ever say a c1j revs happy!) to 7.5k so thats 500rpm more than before. I'm almost certain it still makes power at those revs also but haven't had it on a dyno yet to find out for sure.

[GTphil]

This is also worth a coat of looking over;)

http://www.rtoc.org/boards/showthread.php?t=4744

[Mart]

Thought the RT200 cam in my old Raider was a cracker to be honest. Helped it achieve a 112mph pass @ 21psi at Pod back in the day, so can't be all bad http://www.lancerregister.com/images/smilies/shrug.gif