Zetec Upgrade

[mrud]

I have a 185 H.P. in my Caterham. What is a good upgrade for more HP to this engine without hurting longevity. The engine has the variable cam timing as well as intake runner sizing. Car is my 2004 SV Roadsport w/ 5 speed.

Thanks,

Mike Rudnick

[pksurveyor]

Kent cam should get you another 20 hp.

[DB6]

isn,t 185 enough?

[KiwiBirkin]

Id love 185hp in Grace

[Croc]

Yes but does Grace look good in a red dress?

 

 

 

anyway...back to the point in question - which Zetec are we talking about here? the regular version or the SVT motor?

If it is the SVT then there was a very interesting post by Athens who upgraded his SVT engine to the Kent cam (amongst other things). It was not as trouble free as I would expect for a simple cam upgrade

http://www.usa7s.com/vb/showthread.php?t=1577&highlight=kent

[athens7]

Assuming you have an SVT motor, not a Zetec with ITBs, I would share these thoughts with you. Other than the claims made by Caterham USA, I can find no documentation that the Kent cams are worth 20 hp. Kent Cams refuses to make any statement about these cams, other than to say they are bespoke designs, specified by Caterham USA, and they (Kent) make no representations about any performance gains or problems. How's that for a ringing endorsement? Based on my research comparing the documented performance of stock- and Kent- camshaft equipped motors, I would say the hp gain is more like 8-10, and it will be above 4000 rpm where the benefits are realized. That said, I am happy with the Kent cams, as well as the power of my car. On the stock Avons, I can break the rear tires loose at will in 1st gear, as well as in 2nd under a variety of conditions. Absent very grippy tires, I think any more power would be counterproductive.

 

Mike, before you pursue upgrades, have you had the motor in front of a good tuner? If not, there is likely more to be had from the motor as it sits. The first 2 upgrades I would recommend on an SVT would be a 180 degree thermostat and an adjustable exhaust cam gear. Both are relatively inexpensive, and the thermostat will increase peak torque by allowing the ECU to advance timing further under load due to reduced detonation, while the +2 degree advance in exhaust cam timing will slightly increase power and torque by increasing exhaust scavenging, helping airflow. Air flow is a weakness of this engine set up, due to the pi$$ poor (for this engine) stock exhaust. These 2 items, plus a custom tune from a knowledgable tuner, likely using a Diablosport or SCT programmer, can help realize noticable gains in the performance you feel in the seat of your pants, e.g., an engine more free revving and responsive to throttle input, with torque and hp peaks at lower rpm than the stock engine.

[mrud]

Thanks,

I will take your advice and probably leave well enough alone. Yes, my RS is very fast and will break the tires loose. I was just wondering about pushing the envelope. It is an SVT engine.

Thanks to all.

Mike Rudnick

[TheDingo8MyBaby]

Have you thought about moving to a 6 speed transmission? I hear those are excellent.

[Guest speedcraft]

ok Al...this one's for you after bugging me so much at LOG29...

 

i'll pass on a few things i found along the way in 'finding' more HP...i've got a ZX1 motor with weber DCOE's which is probably the minority in the US for zetecs in caterhams ...i agree with the other posts especially taking a hard look at whether you're really getting 185 now. my set up was supposed to produce "175 hp", but first run on the dyno produced 140 rwhp, a little short but not bad. through jetting and choke changes, another 10 rwhp was found....oh yes, i'm running the kent cams in this set up.

 

next step was a p&p head, big valves [svt sized], and rejetting/chokes [thanks to all those that had advice...although i have to say i never got the same story twice for jetting], cam gears etc...all said, with a stock bottom end and the standard GEMS/caterham ignition which cuts out at 7000 rpm...the same dyno is showing 177 wrhp and 150 torque at the wheel.

 

0-60's clock off in the high 3's, rips through the first two gears and still does well in 3rd. at this stage of tune, its just as streetable as it was with 140 rwhp which is the way i tried to jett it...

 

talking with Ben at Caterham, the ~200 to 210 hp range is what he considers a sweet spot for the zetec, streetable, reliable...going for more gets very expensive and expect more of a race motor than a street motor. i also talked with Dunnel and Raceline and while they advertise zetecs up in that 240 or 250 hp range [at the crank]...better consider fuel requirements and driving style to ensure it fits with your application...race gas for that high compression engine gets expensive fast unless its only track duty you're interested in...i would be interested to hear from those that are producing that type of power [NA] and how the motors are holding up?

 

i'm sure there's exceptions but we're talking about a motor that was producing what, 135 hp stock, and pushing it to produce 100 hp more is huge so i would expect the trade off is driveability and reliability...have to admit though, its just fun playing with the car, not that i need the extra HP.

 

cheers, K

[KiwiBirkin]

Yes but does Grace look good in a red dress?

 

No but she is sure going to look great in blue next week

 

But back on topic.