PontiacBonnevilleClub.com

i have been talking to a guy at work who has modified his last 3-4 cars. By modified i mean $10k-$15k of engine work. We were discussing my car and i was telling him some of the things i wanted to do to it. Basically the list of minor mods, things like rockers, headers, etc.. He told me to turbo it. He said that i can turbo the car and get more horsepower out of it with less boost. I figured you'd have to change the pistons, rods, maybe the cam. He said no, you don't have to change anything except maybe the pushrods to a harder one.

Do you guys think the swap would be a good idea? I think it would cost more to swap it out. More horsepower with the turbo. I think the slow wind up of the turbo would help alot with take off as far as wheelspin.

I have not seen good results with turbo-ing these cars. Member turbossei had an 00 SSEi with a BUILT shortblock, cam, ported heads, etc and he blew a hole in a piston passing a guy on the highway one day.

I cannot see why you'd need harder pushrods. You would want a built bottom end, cam, heads, etc and you'd have a chance at it lasting.

What is it that this guy drives/has driven? Unless he's worked on 3800's and has the knowledge of them that we do, I'd advise you take his advice at face value, and listen to what we have to say.

00Beast wrote:What is it that this guy drives/has driven? Unless he's worked on 3800's and has the knowledge of them that we do, I'd advise you take his advice at face value, and listen to what we have to say.

kind of why i through this at you guys. lol..

only reason i'd do this is if it where a smart route to go. If it's not then i wouldn't even consider it. to me getting enough mods to use my 3.4 pulley will work for me. cause i really don't want to have to order another one. lol.. bought the 3.4 before i knew what i was doing.

but to you the turbo is a bad way to go all around.

Factory turbo is one thing. Turbo on a factory SC car is kinda pointless. Make the SC run better and the engine flow better before throwing a TON of custom work at it making that snail work. $1000 of mainly bolt-ons will have the L67 roaring nicely. Tune it, and enjoy instant power.

A turbo, no matter how well tuned, will always have a bit of lag. And there's no power off-boost. It's not like a SC'd car where the power is right now this instant available. It's press the gas, wait for the turbo to spool, and then go. A smaller turbo will reduce lag and the RPM's it spools at, but won't make as much peak power.

Plenty of newer cars have no real lag in them. A 3.8L will have more than enough torque to get a good sized snail spooling quickly. I'd be more worried about the torque converter than the lag really...

No one here has really done turbo setups, but they were very popular in the W body crowd a few years ago. Instant 12's and "easy" 11's were kind of the headlines IIRC. If you're interested in pure times at the strip, they offer much more headroom for HP down the line, than any M90.

You will be seriously changing how the engine operates, and reliability comes down to how well you design your build, and quality of parts/install. You need to know how to tune pretty seriously, or have a good tuner who can get your car setup. Going this fast means breaking (lots) of transmissions, diffs, probably pushing engine components to break, etc.. I wouldn't turbo a car you have to use as a DD until you're ontop of it. If you have the skills to fabricate the charge piping and weld and such you'll have a fairly decent costing project, but then you wouldn't necessarily be asking the question either!

For experience with turboing these engines, you really have to look beyond this forum. Not many here have experience with it.

interesting views. some of you are saying totally opposite of what i have heard. not a big deal really. the odds of me doing this is pretty slim. part of this post was for me to get your guys view on it and get me some better knowledge of the differences in what our motors can handle and not. i thought the supercharged motor would still need work done to it to make the turbo work on it without blowing anything up right away.

if you guys aren't sure, that's fine. i can ask details somewhere else. actually the guy that told me about it wasn't even sure about how our motors would handle it. he said he'd have to study it more to see what would have to be changed but he thought not very much. again, that kind of baffled me because i thought turbo's needed lower compression and wasn't sure our motors were low enough.

look at this topic as something as getting off the same old day in day out of what do i need to put a smaller pulley on and do i need to build my tranny up. lol.. speaking of smaller pulley, if i put mods on my car to run a 3.5 what other mods would i have to do to run a 3.4? nah, i'll look that up.

The L67 has lower compression than the L36. We're 8:1 or so, the L36 is 9:1 or a little higher.

L67/L32 is 8.5:1, the L36/L26 is 9.4:1.

I was close at least, lol.

Turbo will make more power... especially if your replacing a roots/eaton blower, More efficent and less heat. compression is fine where its at there are a TON of guys running stock L67's with turbo making tons of power and not tearing into the motor... you will need to run a few upgrades at minimum, Upgraded fuel system (pump, Injectors) and a Tune. after that you will need to decide how much boost you will run and need supporting mods for the power level you want to run... TONS of GTP guys on CGP run turbo's in place of the blower... there are many ways to reduce lag, i would not worry much about it just get the right size turbo for you power levels and lag will be somthing you will see isnt a huge consern.

Turboing is not going to be cheap, but it will make more power and can be just as reliable as the roots blower... Ive got 60K on my turbo setup in my MC Z34 and have had plenty of turbo cars in the past ('90 TGP had 140K on it when i sold it, 100% original parts). you just need to decide if you want to spend the $$ and do the work, agian the tune is a big part of it being powerfull and reliable. a bad tune can damage any motor.

Shane

Personally I like supercharged for for heavier vehicles. Centrifugal is a way I would go instead of turbo, but again space is an issue.

if you have a power goal your trying to reach, modding what you have will make a good ammount of power. a hand full of smaller upgrades to make simmilar power is 1 major upgrade... you need to decide if your ready to take on that install... 350whp can be had on a modified stock engine if you take the time and $ to get it there.... 500hp can be made on a turbo engine, it just takes more time and $$.

My MCZ34 is turbo, its much faster then the bonnie but it does have a different feel to it, and slightly lighter but not by much.

S

All of the fastest Bonnevilles were supercharged, FWIW. Bad SSEi was making over 600 WHP with a Kenne Bell or a Whipple, can't remember which one. 8-Ball was running a ported Gen V M90. It can be done, it just takes different mods and a different mind-set. For the OP's purposes I vote he stays with the M90.

redzmonte wrote:if you have a power goal your trying to reach, modding what you have will make a good ammount of power. a hand full of smaller upgrades to make simmilar power is 1 major upgrade... you need to decide if your ready to take on that install... 350whp can be had on a modified stock engine if you take the time and $ to get it there.... 500hp can be made on a turbo engine, it just takes more time and $$.

My MCZ34 is turbo, its much faster then the bonnie but it does have a different feel to it, and slightly lighter but not by much.

S

Your Monte is 600lbs lighter....

00Beast wrote:All of the fastest Bonnevilles were supercharged, FWIW. Bad SSEi was making over 600 WHP with a Kenne Bell or a Whipple, can't remember which one. 8-Ball was running a ported Gen V M90. It can be done, it just takes different mods and a different mind-set. For the OP's purposes I vote he stays with the M90.

While this is true, you have to remember that BadSSEi was replaced by BadGT, which was turboed and made a bunch more power, and then BadGT was replaced by BadGTP, which was TWIN turboed, and made even more power. In fact, I think that BadGTP made well over 200hp MORE than BadSSEi. And while 8-Ball was the fastest street-driven FWD Bonneville, Todd wasn't even close to pushing the kind of power that a good turbo can make.

Simply put, if you want a decent improvement in power without spending a ton of money, build the SC setup. If you want to move beyond about 400fwhp, you're better off going to a turbo, both money-wise, and for reliability.


BTW, a turbo doesn't have to have massive lag to build good power. It's just a matter of picking the right size. Mike Murphy's Turbo GT is a good example; he ran a basically stock L32 with a remote turbo mounted in place of the muffler. That's a butt-load of intake/exhaust volume to pressurize when he put his foot down, but his car spooled very quickly and made easy 13s. It also had the strangest exhaust note I've ever heard...

Id never throw a bunch of HP into a FWD car, especially with these trans'. If you wanna go fast for cheap, Mustang or Fbody(or GTo)

Been done a GAZILLION times, tried and true.

No doubt about it, if you're looking for serious power, turbo is the way to go. You'll spend less in the long run. Reliability is all in the tune and how well designed your setup is. Having driven lots of turbo cars, the lag has never really bothered me. But I do love the instant get up and go of a roots supercharger.

The M90's will make decent power, but only to a point. You can spin them faster with a smaller pulley, but they begin to lose efficiency the farther you go and introduce a TON of heat.

in all honesty though how far do you want to go? 8-ball was running 12's and was still a reliable DD. But it also had the benefit of being torn down and maintained quite often in the intense garage. if you just want to perk up the car then do an intake and tune and then possibly pulley down. if you want a drag car I suggest getting a cheap grand prix shell and turboing it, they are less complicated then the bonnevilles and are lighter too.

a lot of intreresting info. thanks for all the input