31 replies to this topic

[Boxman]

I'm currently rebuilding a standard '95 B5234T engine to deliver ~400HP, and I'm now at the point that I can put the cams in.

What I've upgraded so far is:

- Head professionally rebuilt
- Engine block bored + honed to 81.5mm Wiseco size
- Camshaft checked
- H-beam conrods
- Forged Pistons (Wiseco) and rings

So for the cams, I read a lot of throwing in GLT cams for they have longer duration and higherlifts. I'm asking what the pro's and cons of a GLT cam are. I've heard some rumors;

- Does the GLT cam make the engine run 'less smooth' because of increased resistance due to high lift/duration?
- Is there a risk at high RPM's for "jumping lifters", ie the springs not being strong enough to push the lifters back fast enough?

- Is the mod necessary for 400HP, and is a wall reached if this mod is not installed?

[Jardim]

The cams are a nice addition, a ECU tuned for your setup along with the right timing on the cam gears will allow your engine to run smooth despite the longer duration on the cam. As for the "jumping lifters" i have never heard of such an issue. Maybe someone else can shine the light on the matter.

[BoostedS70]

you mean N/A cams. Glt is also known as a low pressure turbo model, or early models of 850 were N/A glts. but most people on here refer to the glt as a tur bo. I have a 70 GLT and it is the same exact motor as your car just a little higher compression due to a taller piston crown. but cams are the same. you want N/A cams which have more lift and longer duration due to bigger lobes than the turbo cams. these cars also have hydraulic liffters you dont have to worry about jumping lifters. I have never heard of anybody having a problem with that. you say 400hp so im sure you would be able to utilize them, just gota time them and mess around with the overlap try to get it as little as possible.

[Jardim]

I had a hunch he was talking about the N/A cams when he said longer duration and higher lift. Some people say the 93 cams are the most agressive of them all...can anyone confirm this?

[wizzard_al]

"jumping lifters" is something that you might see on an overhead valve engine, such as Chevy V8's, Volvo red block up to B20 engine. It is also known as valve float, when the weight if the lifter, pushrod, and the rocker arm are so much that the spring can't push it back fast enough for the lifter to stay seated on the camshaft at all times. Typically at high rpm, and it means that it is a destuctive way of limiting your rpm. Volvo has overhead cam, so this is a rare event, but could happen if you were twisting it to unholy rpm. But look at lookforjoe's car, he reports over 8,000 rpm, and I don't think he has gone to much stronger springs. (Hussein, correct me if I'm wrong). Other posters have gone over 7,000 rpm with stock valves, so you don't have any real problem to think about.

Note that hydraulic lifters do "pump up", which means that they can't drain oil out of the lifter fast enough, and they tend to lock into one length, which may not be useful for the engine, and that is the hydraulic equivilent to valve float. Same problem, too high rpm for the lifters to keep up. Again, doesn't seem to be a problem for whiteblock engines. Later engines, from mid '99, have mechanical lifters, but they also have VVT on exhaust cam for turbos, and you can adapt those heads and cams, because the head flows better, supposedly, but playing with the cams to adapt VVT cams to non-VVT operation takes a bit of work. There is another thread on this topic.

[lookforjoe]

Others have run the stock (hydraulic) lifters to 7600. I have the later solid lifters, running to 8400rpm.

Sounds like you have a solid build underway.

No reason to worry about idle issues - the NA cams aren't that agressive

[Boxman]

What a great info I always get here. I meant NA cams indeed. So I think I can just safely drop in some NA cams - it's something I would want to do NOW, right? And not later, when the engine is in the car?

Will my engine be ready to run with a stock turbo with the NA cams on the NA timing? Or should I immediately do the timing (i read something about 4 degrees retardation on the exhaust, have to jump into this some deeper) to get the T5 timing window?

Also, what are the power gains I'll be seeing from this, assuming I'd want to reach the 400. Say I reach 400 with NA cams, what would I have reached with stock cams?

[Martijn_B]

With the right timing a guy from the Dutch forum gained around 30bhp with a 19T (335 to 367).

[Korruption]

I have a set of NA cams that I going to sell. Drop me a PM if interested. Good luck to your build.

[850wagonT5]

No one has posted definitive numbers as far as a power increase. I "think" I noticed a "small" difference on the "butt dyno", but if you're spending money building an engine, do the cams right - get CAT's and KNOW for a FACT you're going to be producing a good amount more than stock...instead of guessing. A good performance camset will pretty much always be enough of a difference in pull to where you KNOW they made power. With the GLT cams, it's usually "I think they did something...it seems to pull a little better up top...".

See the difference?

I have GLT's but I'm not convinced they did much. If I was building a head, getting rods, pistons...I'd get real cams.

[Jardim]

You'd probably get or feel more outta the N/A cams if you had a 5 speed

BTW Im going by the sig, 13 is quick would be faster with the 5 speed.

[850wagonT5]

Jardim, on 30 December 2011 - 06:03 AM, said:

You'd probably get or feel more outta the N/A cams if you had a 5 speed

BTW Im going by the sig, 13 is quick would be faster with the 5 speed.

Car already traps 110.

850wagonT5, on 30 December 2011 - 06:14 AM, said:

Car already traps 110.

I should say 110+, walks 335i's hard...walks a friend's 380whp SRT8 hard...haven't lost to stock turbo STI yet. I have NO interest in going manual, really...it's just too much money and time and work. PS, go E85. It's fun.

[dfer10]

who makes performance cams for our cars?

[GltGreco]

dfer10, on 30 December 2011 - 06:06 PM, said:

who makes performance cams for our cars?

not many and as far as i know they are extremely expensive.

[andyb5]

Cat and Enem make performance cams, but both companies are based in Europe and are expensive.

For more specific info, Lookforjoe has Enem cams in his XR 854TGA+ and Falcone have Cat cams in their 850s.

[dfer10]

so really its not worth the cost unless of course you have just tons of green to toss around

[lookforjoe]

dfer10, on 30 December 2011 - 10:13 PM, said:

so really its not worth the cost unless of course you have just tons of green to toss around

It's worth it if your build requires it. If you're working with a stock Volvo turbo & EMS setup, then no.

In the grand scheme of things, you'd get more immediate bang for your buck with a custom intake like mine or Aaron's, than with more aggressive cams.

[850wagonT5]

Ummm...sure, if you ignore the fact that on pretty much every DOHC engine made int he last 25 years, intakes typically dyno 5-8hp (if they work), and a good aftermarket cam set dynos closer to 15-25hp.

Ain't no way a cone intake/short ram/long ram/cold air/etc is going to produce the same power gain an internal engine component in charge of the combustion process is.

Oh, more modern engines like EVO's get closer to 50hp from a good cam set...I highly doubt they're gonna tell you a good intake will see the same power gain. lol.

[98t5M]

lookforjoe, on 30 December 2011 - 10:46 PM, said:

It's worth it if your build requires it. If you're working with a stock Volvo turbo & EMS setup, then no.

In the grand scheme of things, you'd get more immediate bang for your buck with a custom intake like mine or Aaron's, than with more aggressive cams.

Sorry to get a little off topic here, but did you actually notice a gain from your intake? Do you have a write up somewhere? I've been considering doing a setup like yours but I always feel like I'm going to invest a lot of time for something that may or may not be any better than stock.

Thanks

[lookforjoe]

850wagonT5, on 31 December 2011 - 10:50 AM, said:

Ain't no way a cone intake/short ram/long ram/cold air/etc is going to produce the same power gain an internal engine component in charge of the combustion process is.

Intake manifold, not inlet piping,

98t5M, on 31 December 2011 - 11:18 AM, said:

Sorry to get a little off topic here, but did you actually notice a gain from your intake? Do you have a write up somewhere? I've been considering doing a setup like yours but I always feel like I'm going to invest a lot of time for something that may or may not be any better than stock.

Thanks

See above. The short runner/larger plenum intake manifold makes a significant difference to upper end breathing. Again, I cannot speak for stock turbo setups, although Nick says his is vastly improved (with one of Aaron's intakes), and he only has a 19T