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1994 Cadillac Seville STS
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Discussion Starter #1
I was woundering if anyone knew how much HP the stock internals from a 94 N* (vin 9) can handle. I'm planning on a complete rebuild, and hopefully add a turbo/intercooler. I'm going to drop the compression to handle the turbo and give her new cams also. How much can the stock crank/rods handle before I have a hole in the side of my block?? "Eagle" has a set of forged rods that can handle 800 hp, i'm just not sure if it's worth it.
 

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95 Fleetwood Brougham / 01 DTS / 11 CTS Lux / 11 DTS Platinum
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The bottom end of the N* is very very strong. What are you putting this in and how do you plan on controlling it?
 

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1996 Eldorado Sport Coupe, 2009 Black Navigator
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You should read the thread posted by MARK99STS turbo charged N*(If you haven't already). There is a lot of good info there even though I'm sure your question will be answered.
 

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1994 Cadillac Seville STS
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Discussion Starter #4
Sorry.... It's going in my 94 Seville STS.

I've read everything I can find about Mark99sts. His problem is he had an OBDII, and that was his biggest obstacle. I have a "chiped" OBDI and a lot more control over my fuel system. I've already have a k&n Cold air Intake, Dis-4 with accel coils, 3" exhaust, "stage 2" chip, oil cooler, trans cooler.... and a bunch of other goodies. I'm doing a complete rebuild (gaskets, seals, pistons, rings, bearings, cams, ect)
 

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95 Fleetwood Brougham / 01 DTS / 11 CTS Lux / 11 DTS Platinum
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Nice! :thumbsup:
 

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If you use an intercooler, 500+ hp is fine on the stock internals. Limit your boost to 7psi and keep those intake temps down. Ideally you want to retard your timing map.
 

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1994 Cadillac Seville STS
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Discussion Starter #7
If you use an intercooler, 500+ hp is fine on the stock internals. Limit your boost to 7psi and keep those intake temps down. Ideally you want to retard your timing map.
If u dropped my compression to 9 or 9:5:1 do you thing I could go with a little higher PSI, or would 7 be the max. I'll probally stay with 7, but i'd like to know so I can have a little le-way.

I'm so happy i joined this forum :)
 

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'87 Jeep, '10 Thruxton, '00 Duc 748, '01 748R (853cc)
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The problem isn't so much what kind of power the engine can make, but how long before the tranny is toast. 500hp is a death sentence for a stock 4T80E. Your gonna wann save up for an LSD, heavy duty Clutch packs, trans cooler, and all that other good stuff that gonna keep it from blowing up. The only other issue you'll have is trying to control 500+hp through the front wheels without running Drag Radials all the time, or running slicks, and worrying about broken axles. Once you figure all that stuff out, you should be good to go. Good luck with the project, sounds like fun. CHRFab has everything you may need for such a project....that is if you didn't know about them already.
 

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1994 Cadillac Seville STS
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Discussion Starter #9
500 is a lil high for the tranny... i already cracked the shit out of the casing.... i have around 400hp and i cracked the caseing.
 

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1994 Cadillac Seville STS
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Discussion Starter #10
The problem isn't so much what kind of power the engine can make, but how long before the tranny is toast. 500hp is a death sentence for a stock 4T80E. Your gonna wann save up for an LSD, heavy duty Clutch packs, trans cooler, and all that other good stuff that gonna keep it from blowing up. The only other issue you'll have is trying to control 500+hp through the front wheels without running Drag Radials all the time, or running slicks, and worrying about broken axles. Once you figure all that stuff out, you should be good to go. Good luck with the project, sounds like fun. CHRFab has everything you may need for such a project....that is if you didn't know about them already.
Do you know of any other way of bulletproofing the tranny? I already have a Tans-pack (clutches, seals, gaskets, bearings, ect) and a cooler w/fan and the tongue still cracked the output casings (I was being very stupid with her one night on the highway). I thought about re-welding all the joints/seams in the housing, and adding a bigger cooler. I figure if I can keep it cool and tight, and all the bushings tight, it’ll last a long time. I’ll cross that bridge when I get there, but the maximum breaking point for the 4T80E with be a concern at some point.

Any ideas?
Thanks.
 

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1997 Eldorado, 2003 Audi RS6
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Lower compression doesn't mean higher boost is possible, though with lower compression, there's more room in the cylinder at TDC, so more air and more fuel, so more power at the same presssure.

I have heard of about a dozen cracked cases, almost all of them with 1994s. Power won't cause it, it seems to have been a defect in design. Power will cause internal damage though.
 

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1994 Cadillac Seville STS
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Discussion Starter #12
Lower compression doesn't mean higher boost is possible, though with lower compression, there's more room in the cylinder at TDC, so more air and more fuel, so more power at the same presssure.

I have heard of about a dozen cracked cases, almost all of them with 1994s. Power won't cause it, it seems to have been a defect in design. Power will cause internal damage though.

Thats good to know. Are there more weakspots on the casing? Do you know how much hp they can take? Does 500hp still sound about right, provided it's properly cooled and maintained?
 

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If u dropped my compression to 9 or 9:5:1 do you thing I could go with a little higher PSI, or would 7 be the max. I'll probally stay with 7, but i'd like to know so I can have a little le-way.

I'm so happy i joined this forum :)
What specifically have you done/plan on doing?

If you're just going to put in thicker headgaskets, I'd say the same thing.
If you're putting in custom forged pistons, I'd say you could go a bit higher. If you're going to be spending all this money on a custom engine build, it seems like the $500 eagle rods would be a wise investment.
 

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1994 Cadillac Seville STS
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Discussion Starter #14
So far, the parts list contains:

Arias forged aluminum pistons
Sealed Power Rings
Felpro gaskets
Clevite 77 Main & Rod Bearings
Durabond Cam Bearings
Melling oil pumps, Filter relocation and larger cooler
288 deg Camshafts from CHRF with new springs/retainers
3 Angle Valve Job, ported and polished
21lb Injectors
Holley Fuel pump and pressure regulator
MSD Dis-4 ignition controller w/ accel 45k coils

I was hoping to run 9-10 PSI on the turbo, but can live with 7psi if that what you guys recommend (I don’t want to be doing all this again) I’ve been also looking into water/methanol injection to keep the cylinder temp down under full boost.

I know these are amazing engines and want to show all my “LS” 1-6 friends what these babies can really do, in a fully loaded Cadillac.
 

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So far, the parts list contains:

Arias forged aluminum pistons
Sealed Power Rings
Felpro gaskets
Clevite 77 Main & Rod Bearings
Durabond Cam Bearings
Melling oil pumps, Filter relocation and larger cooler
288 deg Camshafts from CHRF with new springs/retainers
3 Angle Valve Job, ported and polished
21lb Injectors
Holley Fuel pump and pressure regulator
MSD Dis-4 ignition controller w/ accel 45k coils

I was hoping to run 9-10 PSI on the turbo, but can live with 7psi if that what you guys recommend (I don’t want to be doing all this again) I’ve been also looking into water/methanol injection to keep the cylinder temp down under full boost.

I know these are amazing engines and want to show all my “LS” 1-6 friends what these babies can really do, in a fully loaded Cadillac.
You realize 7psi is about 500 crank HP, right? Is this going in something other than a cadillac? You are going to have serious traction problems if you're staying FWD.

Your injectors are way too small. at 7psi, you're going to need about 40#/hr injectors. Keep in mind you will be almost doubling the stock HP, which means double the fuel. Stock injectors are 23.5#/hr.

I'm curious about these cam bearings, because N* cams ride in aluminum "pillow block" type saddles. They aren't upgradeable or replaceable.
 

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1994 Cadillac Seville STS
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Discussion Starter #16
I was told I can replace the stock bearing with brass..... thats why i'm asking you guys before we get too into it, I want to have all the bases covered. I'm sure everyone here knows more about them then I do.

I thought those injectors would be a little small myself. I knew I had to gett bigger ones, I just wasn't sure how big. I'm hoping for around 500-600hp, sp i'm in the right ball park.

I guess I'll cross the traction issue when i get there... I know the traction control has worked well for some friends with nitrous on there's, and I'm going to use 18-19" wheels, but I know eventually I'll still run into problems.
 

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I'm a bit of a torque freak myself.. :thumbsup:

One thing I would recommend is to balance your power. What I mean is to not put too much to this motor at any one point on the rpm scale. Too much too low and you'll damage something. Ramp up the power and by all means use those 4v heads to thier potential.

I'd keep the boost in the 6-8psi area, and rev the snot out of the motor. Any engine can handle bigger than typically accepted increases in boost/power at **elevated rpms**

Spend your money on balancing. Static balance the pistons, wrist pins, rods, & bolts. Then send the crank, damper, flywheel, and staticly balanced parts to eagle. Have them straighten, machine, and rotationaly balance it with the proper bob weights.

You'll spend a good $1500 on this process. But it'll not only make power.. it'll live to see those repeated high power and rpm blasts. :thumbsup:

Rich
 

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1997 Eldorado, 2003 Audi RS6
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Lose the felpro gaskets. Their head gaskets are visibly (and to feel) inferior to the factory part. And 7 psi will not be 500 HP. 14.7 psi = double power, minus inefficiencies (supercharger drag, turbo exhaust restriction, etc). It's not uncommon to see a supercharger eat 100 HP at higher RPM, depending on size and pressure.
 

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And 7 psi will not be 500 HP. 14.7 psi = double power, minus inefficiencies (supercharger drag, turbo exhaust restriction, etc). It's not uncommon to see a supercharger eat 100 HP at higher RPM, depending on size and pressure.
Turbochargers are more efficient than superchargers.

And you're assuming flow is linear to pressure, and it's not. The first few PSI will give the largest gains because flow quickly increases when the stock intake restrictions are eliminated. "0" PSIG would probably give you 50hp because the engine doesn't have to struggle pulling air in.
 

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90 Eldo -SOLD-, 98 ETC -SOLD-, 86 XR4Ti Track Car, 07 Ranger
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I'd really like to see your plumbing layout if you're running a turbo, that's where Mark really ended up in a bind. I remember talking to him and he said if he had to do it all over with a turbo he'd set something up like the Squires Turbo System remote mounted turbo setup. I also don't remember which turbo Mark used but at 7 psi he was at 383 WHP I want to say and he was at 430ish last I spoke with him at 11 psi, problem was he couldn't properly intercool his setup due to the plumbing, he had a very small intercooler...

That being said, I'm wondering why no one has wanted to use a centrifugal supercharger mostly to keep the layout simple. I know they're not the best pieces of equipment in the world and they cost a pretty penny, but when you look at how much space there is to fit everything under the hood without radical cutting/plumbing like Mark had to do I don't really see why no one mentions it. Obvisouly they're not as efficient as a turbo, and don't build boost immediatley like a supercharger but in many ways that's a good thing for a FWD application. Afterall if you put too much power down too fast who cares if it's got 500 FWHP when all you're doing is spinning em, as wydopnthrtl already pointed out. Honestly, if you're building a 500+ HP engine do you really care if you burn a bit more fuel to run your forced induction as long as it puts down 500+? If you can weld pipe and have a ton of time to do all the mocking/fitting then a turbo will definatley be cheaper/more efficient in terms of $ spent, but there are other problems to take into account such as the fact that Mark ended up having to run an electric scavenge pump on the oil return from the turbo because it was level with the pan, a remote mount would definatley need this, not to mention some associated lag with the long intake lines.

For a C.Supercharger I mapped it out a while back and you'd need to relocate the battery, fab a custom bracket for the CSC, get a new/longer serpentine belt, cut an intake hole where the battery tray is, then adjust the CSC outlet so it clears the fender/rad support, plumb it up to a FMIC and then back up into the stock intake location.

I'm not saying a turbo isn't a good idea, I just wanted to present another alternative that in my opinion has less fabrication/layout variables to take into consideration:)
 
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