Topic: camshaft questions

[mike89db]

So, to start off I have a 1997 jeep wrangler with the 2.5l. I called clifford performance about the camshafts that they offer for the engine that could.  The guy I talked to said that I can not run a camshaft with out switching to a different injection system because the stock one could not handle a bigger camshaft.  Is this true?  Or can I just reset the computer and it will figure itself out?

On the other hand, I called Delta camshafts and they offer a very mild cam that you can just "drop in" without getting different valve springs or anything else.  Has anyone had any experience with these camshafts?

Thanks for any input!

[sharpxmen]

So, to start off I have a 1997 jeep wrangler with the 2.5l. I called clifford performance about the camshafts that they offer for the engine that could.  The guy I talked to said that I can not run a camshaft with out switching to a different injection system because the stock one could not handle a bigger camshaft.  Is this true?  Or can I just reset the computer and it will figure itself out?

don't have experience with these  but i am guessing that he might have meant there are no tuning options for the ecu - which means the engine could breathe better with the new cam but you cannot give it more fuel by tuning the ecu - there are options for it though, but i cannot really speak on the subject since i did not do a cam upgrade on this motor. Would be interesting to ask him more details, and probably mention that you intend to put bigger injectors and maybe if they recommend a certain injector for their cam (i mean what flow do they recommend and make sure he specifies the pressure at which the injector is rated).

[mike89db]

I see what you mean there.  Basically what he said was that.....If I dropped in the cam the computer would get confused and not know where to go or what to do ( or how to handle the bigger lift/duration)  If what you said is true than in theory I can just buy a set of #24 injectors, correct?  Again, Im not taking your word for it lol.  But it would be nice if that was all I had to do ( besides valve springs and lfiters)

[sharpxmen]

I see what you mean there.  Basically what he said was that.....If I dropped in the cam the computer would get confused and not know where to go or what to do ( or how to handle the bigger lift/duration)  If what you said is true than in theory I can just buy a set of #24 injectors, correct?  Again, Im not taking your word for it lol.  But it would be nice if that was all I had to do ( besides valve springs and lfiters)

there's some confusion with the rating on the injectors - you should check the rating on your specific engine and fuel pressure and make sure the ones you buy have that rating for your fuel pressure, you could end up with lot more than you expect to have and run too rich (or too less and then it's even worse). read this thread i posted http://4bangerjp.com/forums/index.php/topic,7203.0.html - when you look for injectors you need both flow and pressure at which they are rated and you can determine the resulting flow on your engine based on the fuel pressure for 97 TJ (49 psi). You could ask what is the increase in air at max power for that cam (let's say it's 15%) - then you will need roughly a 15% higher injector flow - but for fine tweaking you could also use an adjustable fuel pressure regulator or a piggyback system (like Split Second PSC1). Best is to start from the base of what they tell you the increase in volumetric efficiency at top power for that cam and get injectors accordingly (like i said if they say you'll get 15% more air get close to 15% larger injectors) and then you log your afr with a wideband o2, see if you are too rich or too lean and adjust the fuel pressure accordingly - problem with the 97 is that already runs at 49psi so you can't go too much higher, but for fine tweaking should be enough. If that doesn't do it you need to trick the ecu, some have done volt mod for the MAP sensor, but the best way is with the piggyback unit. read that post, will give you an idea what injectors to look for or if you find one search for the p/n to find the pressure it is rated at if not specified.

[Castr8r]

For what it's worth...
     I'm running a Clifford cam in my '89 2.5 L engine with a Clifford header attached also.  This throttle body engine has been running great for about 3 yrs. and has a lot of low-end torque.  It's been known to spank a six on more than one occasion- on the street as well as on the trail.  I can't find the cam specs right now; I'll look some more tomorrow.  I am running the stock motor management system.  Your experience may be different!   

[mike89db]

Well, I think I am leaning towards the delta camshaft now.  It is probably safer than the clifford cam to "try" and run it with the stock fuel system.  I already know this cam will work anyways.  It would be nice to use the clifford cam, but this all seems pretty confusing to me lol.

[YJmechanic]

i dont know if he is talking about specifics to the tj ecu or not but i am running almost the most aggressive cam that clifford offers with the stock ecu.  i have 19lb injectors and 4.0 tb with borla 4-2-1 header.  i also have the intake opened and exhaust is almost free but all i did was reset the ecu and no problems.  my motor was also aggressively built but you should have no problems with a rv cam that is not to radical.  clifford has there own injection system and they push it hard.  i talked to them years ago about it when i did mine and the numbers are impressive but would have doubled my build cost.

[mike89db]

i dont know if he is talking about specifics to the tj ecu or not but i am running almost the most aggressive cam that clifford offers with the stock ecu.  i have 19lb injectors and 4.0 tb with borla 4-2-1 header.  i also have the intake opened and exhaust is almost free but all i did was reset the ecu and no problems.  my motor was also aggressively built but you should have no problems with a rv cam that is not to radical.  clifford has there own injection system and they push it hard.  i talked to them years ago about it when i did mine and the numbers are impressive but would have doubled my build cost.

That is exactly what I thought they were trying to do.  I have researched camshafts from them on both jeepforum and here.  Everyone has had no problem with the stock fuel sytem.  As far as I know anyways.

[sharpxmen]

That is exactly what I thought they were trying to do.  I have researched camshafts from them on both jeepforum and here.  Everyone has had no problem with the stock fuel sytem.  As far as I know anyways.

you will need to at least upgrade the injectors or the cam won't give you the full potential (that's the whole point to get more power for which you need more fuel). like yjmechanic said he changed the injectors, i would pick his brain some more and maybe use the same cam since he's got good results.

[mike89db]

I will deffinatly upgrade the injectors and probably a 4.0 TB.  So YJmechanic, any other information you know of that could help me?

[YJake]

Upgraded camshaft in a 2.5L?

Hrmmms. More information please!

[jfrabat]

I have a MOPAR camshaft, which is the most aggressive cam shaft they sold for this engine for street use (dont remember the exact numbers, but I can get them if you want; hese are almost impossible to find nowadays).  I have yet to drop it in (will probably do so in a week or so), but it does require new springs (stiffer), which I already have as well.  Also, I have the 24# injectors (mine is YJ), so I am expecting big things out of the cam...

[YJmechanic]

actually i ran the new cam on the stock injectors for a good time and had no problems but i think i did get a bigger benefit than most when i changed to the bigger injectors.  as far as the springs i ran the entire kit from clifford due to the fact that they were worried the stock springs could not handle the increase in force but they told me that with new ones (cause my head was already rebuilt) may fair ok for a time period,  the kit is not that much though and i have better faith in the upgraded parts.  the cam i got if im not mistaken was their 426 lift cam.  they have pre set perameters that they swear by and mine is the second to most aggressive cam they have,  i think the biggest is around 502.  clifford was extremely helpful in the entire transaction and i would definetley buy from them again

[jfrabat]

mine is a bit more aggressive; It's a .450 lift 256 duration, but I did get the Mopar high performance springs to go with it.  I do have already installed the bigger injectors, so I hope I get to see big differences in power output.  If I could get a bit more torque in the low end, I will be one happy camper!  As it is right now, the butt-dyne really shows the difference on how the torque picks up at 2,500 RPMs, but I would prefer the troque to come in a bit lower...

[YJmechanic]

well it depends on how you set up.  higher lift cams tend to not kick into power band as low.  i rely on my gears to get mine going then when the rpms come up i have all the power i need,  were the mopar springs doubles?  never saw the mopar kit