Some opinions on High Compression and 4.2 w/ M90 builds needed

[Kiljosh]

Well folks, few quick questions.

While the car is down I figured I would finish the rebuild of the motor and that just leaves me needing a bottom end and a tranny.

I know I am going 4.2-4.4. I'll either be picking up the 4.2 stroker kit from Morana for 2g's or else finding my own pulled parts to make this measly 3.8 to a 4.2. If I make enough cash the whole block is getting pulled and sent to morana for a 4.4 kit or else SSX for their 4.3 Long rod.

Questions..

What is the highest compression ratio I can set my motor at with valves that produce .507/.504 lift? Granted I will most likely swap cams for the 4.x but keep my 1.8 rockers.

My heads also flow 193/131 cfm @.550". Will this be enough to reuse the heads on a 4.2-4.4 motor?

How close will I be to maxing the flow in a forced induction and in a high compression motor?

What would YOU choose with a given budget of about 6 grand, me doing labor.

Does anyone have any links to times or videos of a High Compression v6?

My other idea was to fit an m90 to the 4.2-4.4, welding the silencers, putting a new pulley and raised top on the charger and finally finishing with a FMIC.

How would I go about fitting an m90 onto a 97-early 98 4.2 motor? I am 80% sure these are internally balanced and Supercoupes are external. This difference on top of the new 3-belt drive Id have to put on has me wondering if it's even possible without machining the crank.

I am definitley going forged Rods/Pistons and at the very least a steel crank, whats the approx. max PSI I could put into a low CR(8.0:1) 4.2 motor? 4.3? 4.4? Is there a difference between the 3? Im assuming the bores are overbored in the 4.4 not just stroked so how thin do the walls get? Is it safe to run boost on a motor this hogged out?

This is going to be a Street/weekend warrior build. I would like to be in the neighborhood of 300hp. Which will get me closer, compression or boost?

ANY answers you can give are appreciated.

[crazeflier07]

Boost it. I thought you were selling your car?-
~Jon~

[Kiljosh]

I just have it up to see what I can get for it. A good enough deal comes around I will sell but it doesnt make sense to sell a nice car like this for 3-4 grand that just needs 2g's of bodywork to look perfect. What am I going to buy with that 3-4g? A cavalier? No fuck that.

[Kiljosh]

And what do you mean by boost it. You think the m90 on a 4.2 would work? If I cant do that maybe TMA down the road but its so pricey.

[crazeflier07]

Quote: Originally Posted by Kiljosh I just have it up to see what I can get for it. A good enough deal comes around I will sell but it doesnt make sense to sell a nice car like this for 3-4 grand that just needs 2g's of bodywork to look perfect. What am I going to buy with that 3-4g? A cavalier? No fuck that.

Lol, I feel you on that. Thats the same way I feel about mine. I like turbos so thats what I would do but I dont know about the M90. I heard that the M90 swap could be complicated and cause a lot of headaches. I do know that SuperSix is working on an adaptor that you could mount a cobra M112 roots blower on top. As for the having 6 grand to spend. I would do a SSM Stage 3 power pak and get a TMA turbo like what Darkshadow and Rydog have. I dont know what else you have do drivetrain wise or suspension wise but maybe put some money into those parts and you'll definetly have a sleeper there. As for max psi if you are planning on building a stout bottom end and running that low of compression, you could probably run some serious psi numbers. Dont know for sure but maybe like 20 psi or higher. You could cram a lot of air in there.
~Jon~

[Kiljosh]

Well I am confident I could perform the M90 swap onto a 3.8 without a problem. Just onto a 4.2 is a different story.

[Brent]

Nothing should change with the swap. The only thing different is the 4.2 Crank in the block.

[Kiljosh]

But for a 97, the easiest thing to do would be to use a 97-e98 4.2 right? But they arent balanced different from a supercoupe?

I just dunno about the pulley system.

[nmaraijko]

Looks like you have some good goals. Personally I would stay away from the M90. I tried to adapt a t-bird sc set up to mine, and lets just say I now have a vortech s-trim and a garage full of supercoupe crap (for sale). If you do the work your self maybe, but the labor time to pay someone would be outragous. There are many problems you will run into including re-locating your break mastercylinder, abs, tranny cooler (auto), and sway bar. Also you will be limited to single port heads (pre-1996 or SC at that) and the sc intake, which are no where near as good as spilt port stuff. As for your head flow numbers, a 4.2 or 4.4 will need more air than a 3.8 / 3.9, I have seen guys lose HP with strokers (but gain lots of TQ). So I would find better flowing heads. If you are worried about blower cost find a used vortech or pro-charger online. They are much better blowers. If you are dead set on the m90 contact Tom Yentzer at Supersix as he attempted to do my conversion and can give you the 411. Also if you want I am selling my M90 set up (complete minus some bolts and gaskets) as well as my vortec s-trim-less than 2,000 miles on it, (pulleyed for 13psi) as Im going to a TMA turbo when I get back from Iraq. Well hope this info helped some.

[DarkShadow]

^Very good advice. The M90 might be a pretty cheap option itslef, but by the time you factor in everything it takes to hook one up, and the comparitively crappyish gains from it, they aren't the best blower IMO. If you want an SC, I would go with intercooled Vortech or a procharger set up, and do the split port swap PLEASE.

Couldn't give you exact numbers at all for your other questions, but I would recommend a low compression/high boost system over a high compression/low boost. Overall, boost makes more power than compression if you do a built bottom end like you are wanting to. As for how much boost, look at Justin running I think it's 17psi on his weekend track turbo car with a STOCK bottom end. I wouldn't recommmend it for a DD, but I think it's pretty safe to say on a built bottom you could do 20 safely. You will want to upgrade to a Cobra double pump tank with either twin Focus pumps of twin GT pumps. Bigger fuel rails, lines, etc. But you would be a monster. Like I've said before, I would love to see what FULLY built 4.2 would do with around 20+ pounds of air.

[rydog]

I spent almost 6k on just on my turbo kit and supporting mods

TMA kit with my options = 4000
injectors = 300
BA MAF = 239
fuel pump = 100
misc tools = 75
header wrap = 75
guages = 100
SCT tuner = 400
dyno time and tuning = 600

Grand Total = 5889

and thats not counting the little things i had to get new oil, filter, tranyfluid, antifreeze, zip ties etc. etc. etc.

so you will def spend more than 6k for a motor build and a power adder

[Kiljosh]

Quote: Originally Posted by nmaraijko Looks like you have some good goals. Personally I would stay away from the M90. I tried to adapt a t-bird sc set up to mine, and lets just say I now have a vortech s-trim and a garage full of supercoupe crap (for sale). If you do the work your self maybe, but the labor time to pay someone would be outragous. There are many problems you will run into including re-locating your break mastercylinder, abs, tranny cooler (auto), and sway bar. Also you will be limited to single port heads (pre-1996 or SC at that) and the sc intake, which are no where near as good as spilt port stuff. As for your head flow numbers, a 4.2 or 4.4 will need more air than a 3.8 / 3.9, I have seen guys lose HP with strokers (but gain lots of TQ). So I would find better flowing heads. If you are worried about blower cost find a used vortech or pro-charger online. They are much better blowers. If you are dead set on the m90 contact Tom Yentzer at Supersix as he attempted to do my conversion and can give you the 411. Also if you want I am selling my M90 set up (complete minus some bolts and gaskets) as well as my vortec s-trim-less than 2,000 miles on it, (pulleyed for 13psi) as Im going to a TMA turbo when I get back from Iraq. Well hope this info helped some.

Thanks for your reply!
I was not aware I would have to relocate the front swaybar with an m90 swap...thiis is a problem.How would you go about getting around this, Im not good with suspension. Is it even possible to relocate it around, im guessing, the charge tubes?

And are you sure I need pre96 or SC heads for the swap. All the faqs I have read online say the only thing I need to change is the lower intake, fuel system, pulley system, and relocate your brake stuff. I have not heard of this. I will talk to Yentzer though and see what he thinks.

Quote: Originally Posted by DarkShadow ^Very good advice. The M90 might be a pretty cheap option itslef, but by the time you factor in everything it takes to hook one up, and the comparitively crappyish gains from it, they aren't the best blower IMO. If you want an SC, I would go with intercooled Vortech or a procharger set up, and do the split port swap PLEASE.

Thanks for your reply man, but I am staying singleport, I want to reuse my heads. I spent 2-3grand on this top end now Im not going to get rid of it all and start over COMPLETELY again lol. Besides I can make just as much power as you split port guys with some bigger valves and more lift.

Quote: Originally Posted by DarkShadow Couldn't give you exact numbers at all for your other questions, but I would recommend a low compression/high boost system over a high compression/low boost. Overall, boost makes more power than compression if you do a built bottom end like you are wanting to. As for how much boost, look at Justin running I think it's 17psi on his weekend track turbo car with a STOCK bottom end. I wouldn't recommmend it for a DD, but I think it's pretty safe to say on a built bottom you could do 20 safely. You will want to upgrade to a Cobra double pump tank with either twin Focus pumps of twin GT pumps. Bigger fuel rails, lines, etc. But you would be a monster. Like I've said before, I would love to see what FULLY built 4.2 would do with around 20+ pounds of air.

Thats what Im saying, you dont see 4.2's with massive boost numbers around. It would be fun. I juts cant decide on which. The high compression option sounds good because I dont have to do anything custom really, just more porting and some longtubes. Maybe 13:1, it'd be so snappy. Forged bottom end on 13:1 CR, track day comes and I bolt up a 50 shot of nitrous and feel the glory of HC+NO2=good times. And if someone comes in here and says Im going to blow my car up Ill e-slap them. Im going to get dyno tuned, then a nitrous tune on the dyno done.

Quote: Originally Posted by rydog I spent almost 6k on just on my turbo kit and supporting mods TMA kit with my options = 4000 injectors = 300 BA MAF = 239 fuel pump = 100 misc tools = 75 header wrap = 75 guages = 100 SCT tuner = 400 dyno time and tuning = 600 Grand Total = 5889 and thats not counting the little things i had to get new oil, filter, tranyfluid, antifreeze, zip ties etc. etc. etc. so you will def spend more than 6k for a motor build and a power adder

Thats going with a TMA kit, which I said nothing about. I dont want to TMA it because its so expensive. If I turbo I will just build my own kit based off his designs. I am not going to pay 4k for some headers, a turbo, fmic, and some piping. If he would drop his prices down more he would sell SO much. Hes just a rich mans option at this point lol.

However, I have considered just buying the piping off him and tracking the rest down myself.