Engine/Transmission (1998.5 - 2002) Cams & Spool

[Luke Warmwater]

I have bothered a few of you via PM with the following question but here it goes for public thrashing...



I knows twins rock but at this point for the sake of argument they are not in the picture. I am in Denver at 5k' altitude. I want to to run the biggest single charger I can. I don't tow, don't lug it around, and I have a 5sp. With current setup my 35/12 lights at about 1500-1600 rpms but I can't keep it cool as should be expected. I have ridden in dbook"s 01 ho with KSB1 that lights around 1700-1800 rpms with super mentals and drag comp. Although it still get's toasty pretty quick the higher spool up is not hardly noticable IMHO. I would like to try some mach4s and a full B1 and wonder a few things...



Where would that turbo light up?



How much would spool up speed be lowered with a cam?



To what degree would a B1 cool mach4s at this altitude?



I can make my mach2's smoke now if I want but I can also drive pretty clean just paying attention to when I step on the go peddle. I guess I want to avoid something that flat out cannot be driven period without crazy smoke and also not sure that spool up over 1900-2000 would be that much fun either. Thoughts & Opinions? Thanks

 

[Luke Warmwater]

This is TDR right... no one has any experience with a cam?

 

[Chipstien]

I was going to return your email but I figure I just post the email here. I have talked to a couple of guys with cams and both said that they wouldn't spend the money on one again. They said that the gains didn't justify the cost. I personally would spend the almost 2000 from the cam and put it towards twins instead. Figure the turbo will be in the 1700 range. That puts you at 3500 to spend on twins. You would just need a little more dough. However if you are still set on a single then skip the B-1 and get the B-1-2. At your elevation you would be much happier.

 

[Luke Warmwater]

Gerald, Thx for the info! Did they happen to mention if their cams had any affect on lowering spool up rpm's?



Regarding twins... I have talked to a few guys out there and what I am getting is that with twins by the time you are done can put $6-$8 K into it real fast. Yes the twins themselves can be had in the $4500 range but then I would also need to do studs and o-rings as well. My thoughts were that I know some of the cams(PDR) can be had for $800 and I can have it installed locally for $500 which would put me at $2800 with B1 & cam verses at least $6k for twins. If I am way off hopefully someone can enlighten me. The main question is will the cam really bring the lightl up of a full B1 at my altitude, down to a reasonable level which for me would be around 1900 rpms? I'm not really worried about EGT reduction with cam just spool up reduction.



Thanks

 

[KLockliear]

I was going to return your email but I figure I just post the email here. I have talked to a couple of guys with cams and both said that they wouldn't spend the money on one again.

Whose cam were these two guys running?

 

[Chipstien]

One was a PDR and the other was a DD. I am not saying any names and these were just 2 of the many people that are running cams. Obviously opinions vary widely. I figure at some point I will get a cam but there are some other things that are more important first..... like twins. Oo.

 

[Chipstien]

Luke, they both noticed that they spooled sooner and smoked less. However how much is the question. Keep in mind that niether were dissapointed in the cams... . they just felt there was more bang elsewhere. It could just be that they expected the gains that you get from a gasser and obviously that doesn't happen. Who knows though.

 

[jmeehan]

I've toyed with the thought of a cam also. If nothing else I figure it will help optimize whatever turbo setup I end up with.

I'm leaning towards a Dodgzilla 40/35 hybrid, and I figure with a cam it ought to spool even better, and maybe makeup for my exhuast brake restriction.

My one thought though is, if a cam helps in some areas, what and where does it loose?

 

[Chipstien]

I've toyed with the thought of a cam also. If nothing else I figure it will help optimize whatever turbo setup I end up with.

I'm leaning towards a Dodgzilla 40/35 hybrid, and I figure with a cam it ought to spool even better, and maybe makeup for my exhuast brake restriction.

My one thought though is, if a cam helps in some areas, what and where does it loose?

Everything I have heard says the only downfall is a lighter wallet. Everything else is the same or better.

 

[Bova]

Luke warmwater, I'm running a Enterprise cam. On the dyno It made exactly the same horsepower and torque... but it made it 400rpm earlier,less smoke,quicker spoolup, and 200 deg. cooler egt's.



With the 5 speed at your altitude the B-1 would be nice with a cam, but mach 4's are gonna give you some heavy smoke, I don't know If a B-1 can clean them up at that elevation even with a cam.

 

[Luke Warmwater]

Thx for the replies. I was hoping I would hear something like it helped my turbo light 100 rpms sooner or 200 RPMs sooner. Give me something concrete Man, I wish there were more bombers up here at altitude that have already spent all the money trying bookoo setups lol. I'm almost ready to buy a full B1 and KS housing and start doing my own R&D. Another thing I would like to understand better is what effect a big slow spooling turbo has on EGTs at less than spool up RPMs. I know my 35/12 catches up real fast off the bottom but I played around checking the effect of puttin load on the motor at lower rpms and watching EGTs. It was hard to get them past 800 before the turbo lit. Let's say you had a full B1 and it doesn't light until 2k RPMs. You start throwing fule at it at 1600... how hot do things get before it starts spinning? Keep in mind I am considering an empty truck and not pulling 80,000 lbs like some others seem to find fun. This is a street racer with 4. 10s. One would think that technically speaking there has to be a way to design a single charger that can spin up at lower RPMs and then open up when things start to get interesting

 

[rubberneck]

Sorry, no cam, but I do have a full size B1 and mach 4's. I would tell you at sea level where im at, the B1 lights pretty hard in the 1800-2000 rpm range, just about what you are thinking it would. I have driven at altitude, and it does take a very gentle and patient right foot to keep the smoke down. Not horrible, you just have to be aware of it. However, while I was up therer, I never really jumped on it to see the difference in spool on a hard launch. Didn't test for peak egt's either, sorry. Had the wife with me the whole time, and she yells at me i start to drive stupid as she likes to put it. LOL. At sea level, my peak egts are in the high 1500's to low 1600's flat out 0-115 mph run with my 6 speed. I do notice a significant difference when the temp and humidity is up. Truck runs "flatter" for lack of a better word. Spool seems slow and just feels down on power all the way around. I know this is normal, but it seems as i have gone bigger on injector, this "syndrome" has gotten more noticeable. Runs like a violated primate when the temps are 85 and down though. Since you don't tow, I would go with the full B1, it seems to do well down here. It cleans the 4's up great at sea level, but as stated in an earlier post i can't answer the same for altitude.

 

[Luke Warmwater]

Now that's what I want to hear lol. If a cam will get my spool back to sea level, levels up here, then 1900-2000 turbo light with mach4s is fine with me. I can drive around smoke...