94bamf

I plan to do a cam swap in my GTO, seems like the 918's are the best, cheapest, easiest springs to use. What do you guys think, anybody had bad luck with these. The cam I am going to use is only .534" intake and .544" exhaust, so its not like I am going to be pushing them to there limit or anything.

Damian

iTrader: (89)

918's are not junk. They work very good...

Cal

iTrader: (1)

They're probably the best single spring out there. I've been beating on mine for two years and 15,000 miles. I just pulled a few and measured seat and open presure, and found it to be at or above specs for new springs.

Inspector12

iTrader: (29)

Yeah but I would not call them the least expensive. The SDPC spring kit includes Manley springs good for .600" lift and Titanium retainers for $178.95 That is cheap and I have used them on a number of cars without a problem. Comp Cam 918's $168.95 and Titanium retainers $174.95. Now with your cam you maynot need the titanium retainers but for $10 more they are giving you the Tit. retainers and it is just less valve weight. JMO though. Good luck!

94bamf

Are the 918's some what like stock springs in design? How much better are they than LS6 springs? At what rpm are titanium retainers required or even helpful? Do the LS6 springs require seats? Do the 918's not require seats?

Damian

iTrader: (89)

You do not need Titanium retainers with 918 springs. I've installed several sets using stock hardware and no problems. Just order a set of 918 springs and run with it.

Cal

iTrader: (1)

Yes, they are of the beehive design and look very similar to stock springs, just stiffer. They are a lot stiffer than LS6 springs.

Inspector12

iTrader: (29)

94BAMF- The stock seats are fine for the 918's or LS6 or the Manley's. No Tit. retainers are not needed yet, but are recomended with some shops more aggressive lobes like MTI's C-2 224/224/ 581/581 112+4. Since he just mentioned lift and no specific specs I thought I throw my .02 in about it if you get a cam only installed at MTI they use the Manley springs so they are proven in my mind as far as the amount of use they have had.

94bamf

You got me interested now, what is SDPC?

I just noticed through Summitracing, the 918's are rather expensive.

bigdsz

iTrader: (1)

The Comp 918's are great springs and I had them on my stock heads so I have no bias, however the Manley/titanium set up is a winner price wise. As you are probably aware much of the LSx performance parts are over priced, relative to SBC.

Inspector12

iTrader: (29)

SDPC they are a sponcer to the right. www.SDPC2000.com go to engine components and then valve springs and youwill see the SDPC spring kit. It is all Manley stuff. Good luck.

94bamf

Well the deal at Thunder Racing for the cam, springs, and pushrods is an amazing price. $600 for all. Only problem is I was going to get a Lunati cam, instead I was thinking about this one from Thunder.

Thunder Racing Custom Split Pattern Camshaft for Nitrous/Supercharger applications- 224/227 .563/.569 114 LSA (This cam will check in the 226 range on the exhaust lobe.) 2200-6800 RPM Power Band. Excellent mid-range & high RPM power. Automatic cars require computer tuning and it is recommend for optimum results on manual transmission cars. Due to the fast ramp rate of this camshaft, the use of 1.8 rockers is not recommended.

The main reason I am going with a split duration cam, is I am not going to put headers on this thing(for a while at least). They cost $1K plus, and I refuse to pay that for headers. If Mac, Flowtech, Hooker, etc make some cheaper headers down the road, I will buy them.

Here is the car and mods.
2004 GTO
Planned mods.....
Ported Throttle body
ASP underdrive pulley
CAI....already done
Vig or Yank 3400-3600 stall converter
Shift kit...maybe
Trans cooler
HP tuners
Full exhaust with x pipe, no cats, 2.5 inch.

Pro Stock John

iTrader: (34)

918's are a good spring for a <6600 rpm setup.

PREDATOR-Z

What's the point?? You'll just be choking your motor and would not benefit from the cam. get headers first or wait.

94bamf

I believe the GTO manifolds are quite a bit better than the F-body manifolds. Obviously not nearly as good a Full Length headers, but the rest of my exhaust will be free flowing.

I am kinda looking at it as a project not many people have done, a decent sized cam without headers. Call me crazy/stupid....

66deuce

iTrader: (1)

i would go with a little more duration on the exhaust side to help crutch the factory manifolds,something like a 224int./230exh. but like predator said you won't get the full benefits from the cam until you have headers.

eallanboggs

iTrader: (1)

The 918s are beehive type as are the GM factory springs while the Manleys that come with titanium retainers for under $180 as was mentioned are straight style not beehive. What a deal! I just received a set from SDPC. I also bought the spring compressor tool they sell for $60. When I received it from UPS I went to the KD Tools website and found you can buy the spring compressor directly from them for only $41, but that doesn't include the air fitting which I didn't need anyway since I already have one. I have a set of 918s on one LS1 and will soon install the Manleys on my other one. The 918s have been in for several years now with more than 20K miles. I do want to report that soon after I installed them I pulled my heads to ship them out to have them CNCed. I removed the valves before I sent the heads out as I was having Manley SS valves installed. I had to wriggle one spring and retainer to get it loose from the head as it was stuck. The retainer and spring came loose, but the bottome coil of the 918 remained attached to the head. The spring had broken at the first coil wrap at the bottom. I was very lucky to say the least in that it broke at the first coil wrap instead of the in the middle. My valve did NOT drop thank goodness! I have not pulled the rocker cover since the heads were reinstalled to see if any other springs have failed as the motor is running like a scalded dog. Comp relaced the spring and ask me to ship the broken one to them for inspection. I think that spring was an abberation and not an indication that the 918s have a problem in general altho I must admit I might not feel that way had that spring broken closer to the middle and allowed my valve to drop.

94bamf

Well I was going to use this Lunati.

HYDRAULIC ROLLER: Good Pro-Street cam with choppy idle. Engine modifications required (valve spring). 2500-6000
287° 298°
222° 230°
.534" .544"
.314" .320"
114° Sep
110° Int C/L
01°BTC 41°ABC /
53°BBC -3°ATC

The cam is cheap at $350 from summitracing, but the Lunati pushrods they recomend are $140, and the comp springs are $170.

Thats $660, when I can get the thunder racing setup for $600....

99ssleeper

iTrader: (98)

I am using the SDPC Manley kit too. 13,000 miles and no problems.....cant beat $180 for springs and Ti retainers, especiall when it's a known name.

My $.02

jrp

iTrader: (16)

yes, but the SDPC manley springs only have 112 seat pressure. granted this is not a super agressive XE-R cam but still, the 918's have 130 seat and 350 open.