stock turbo?

[ikle]

How much boost is too much for the stock turbo?I read a post that said that every turbo has a sweet spot and anything above that would just build up to much heat.So if you intend to go over that sweet spot it would be better to upgrade to a bigger turbo. I plan on running Razor's alky kit with my combo and up to 20lbs of boost,for now,but as everybody knows what happens when you go with alky,you become an alkyholic.Thanks,ikle

 

[JP112_89]

turbo

I "heard" 22#'s. A few people have run more though.

 

[gusszgs]

I have run 22lbs with the stock turbo so far, with 0 KR and the alky set at about 5-6. O2's are between 790-800. I have a feeling I could increase it but don't want to push my luck.

 

[scojack_2001]

How much boost is too much for the stock turbo?I read a post that said that every turbo has a sweet spot and anything above that would just build up to much heat.So if you intend to go over that sweet spot it would be better to upgrade to a bigger turbo. I plan on running Razor's alky kit with my combo and up to 20lbs of boost,for now,but as everybody knows what happens when you go with alky,you become an alkyholic.Thanks,ikle

I used to run 25-26psi on my ported stock turbo at all times when I had it on the car. It took me to 11.98@111 on the stock IC and convertor in a full weight GN. I still have it and its still in good shape too. All depends on the tune. Car at the time would normally run 12.1-12.2 in the 109mph range at the track. 93 octane pump gas and Razor's single nozzle.

 

[ikle]

Thanks for the info,I'll be keeping my stock turbo for now, until I max it out.Thanks again,ikle.

 

[Turbo6Smackdown]

I used to run 25-26psi on my ported stock turbo at all times when I had it on the car. It took me to 11.98@111 on the stock IC and convertor in a full weight GN. I still have it and its still in good shape too. All depends on the tune. Car at the time would normally run 12.1-12.2 in the 109mph range at the track. 93 octane pump gas and Razor's single nozzle.

And that's with a stock intercooler, heads, and converter. Wow. Imagine what it would do with a better ic/heads/converter.

 

[Blazer406]

It all depends on how much work has already been done to increase airflow thru the engine...... if it is all stock..... it might get 25 lbs + ....... GN1's or heavily ported irons.... you might not even get over 20-22 before turbo is done. If the tuneup is there.... your timeslip will ultimately tell you if you are making any more power..... there is no "magic" number IMHO for a "max" boost level...... you just gotta try it and see what the slip says....

 

[murphster]

And that's with a stock intercooler, heads, and converter. Wow. Imagine what it would do with a better ic/heads/converter.

You'd be surprised. There is not as much gain as you would think going to better heads, converter, cam, IC. I am basing this on my and a few friends experience the last couple of years with many cars going low 12s and a couple high 11s with the stock turbo.

Like mentioned in the post above, the stock turbo seems to run out of steam on even a stock combo even in the low to mid 20#'s of boost. So besides not being able to make use of the extra flow of better heads, the same thing results when going to an upgraded cam and converter. A stock cam or similar keeps the rpm range lower where the stock turbo works best. The stock converter also keeps the rpms down and will work very well as long as you can 60ft. With a smaller converter, you may be able to 60ft a little better but you'll be running higher rpms through the run and maybe going out of the sweet spot with a stock turbo. Seems like a good stock D5 or a restalled 12" work well.

As far as the IC, using alky really negates the cooling advantage of a larger IC versus a stock setup. A better flowing IC that has less pressure loss versus stock is where I'd think the most gains would be made. However, you rarely see something like a good flowing front mount IC on a car with stock heads/cam/converter and a stock turbo, so who knows.

Besides the regular upgrades, the best things for a stock turbo are alky, a good 60ft, and removing as much weight from the car as you can. Good air doesn't hurt either. At over 22#s, the gains become smaller for a stock turbo but there does seem to be some gain going up to 24-25 on a stock head/cam setup.

 

[scojack_2001]

And that's with a stock intercooler, heads, and converter. Wow. Imagine what it would do with a better ic/heads/converter.

Pretty much. Ive gone the times in my sig on my current setup. I wouldve liked to have had a wideband to tune with the stock turbo. I do remember having to crank the timing up pretty good to get that 11 second stock turbo pass. I think the 1/8th mile on that pass was a 7.58. I can dig around for the timeslip.

You'd be surprised. There is not as much gain as you would think going to better heads, converter, cam, IC. I am basing this on my and a few friends experience the last couple of years with many cars going low 12s and a couple high 11s with the stock turbo.

Like mentioned in the post above, the stock turbo seems to run out of steam on even a stock combo even in the low to mid 20#'s of boost. So besides not being able to make use of the extra flow of better heads, the same thing results when going to an upgraded cam and converter. A stock cam or similar keeps the rpm range lower where the stock turbo works best. The stock converter also keeps the rpms down and will work very well as long as you can 60ft. With a smaller converter, you may be able to 60ft a little better but you'll be running higher rpms through the run and maybe going out of the sweet spot with a stock turbo. Seems like a good stock D5 or a restalled 12" work well.

As far as the IC, using alky really negates the cooling advantage of a larger IC versus a stock setup. A better flowing IC that has less pressure loss versus stock is where I'd think the most gains would be made. However, you rarely see something like a good flowing front mount IC on a car with stock heads/cam/converter and a stock turbo, so who knows.

Besides the regular upgrades, the best things for a stock turbo are alky, a good 60ft, and removing as much weight from the car as you can. Good air doesn't hurt either. At over 22#s, the gains become smaller for a stock turbo but there does seem to be some gain going up to 24-25 on a stock head/cam setup.

Pretty much sums it up.:smile:

 

[pacecarta]

while i'm eager to get the 86 back in shape for runs at low low 10s i might just hold off for a week or so
for now ive got a a temp 109 motor w/na crank in the 86
stock turbo ,stock heads ,stock rockers,stock cam ,stock lifters rods, pistons ,mains, even reused old stock gm head gaskets and head bolts
because its a temp motor i keep most of the 86s parts inplace on the car so it has
cas V1 , 70mm throttle body on a precision 65 plenum ,razor alky ,fastB2b ,37#inj(expected it to run to 11.5s) , th400 w/ brake with a low stalling (1psi at 2650) 10" vigilante converter , moser spool, msbc-1 boost controller , 3" ATR external gate downpipe with 2 3/4 duals, 28x10.5 et drags

the only runs it made at last event last year ( i wasnt driving) it went 12.5 107 at only 18psi at 20 degrees timing 8psi launches (spools quick) all while keeping the rpms under 4800



so I might get to see if the huge i/c matters much

on the op question , i ran many 12.0s at around 108 at 24-21psi , stock heads,cam etc ,stock duttnecked IC and alky , 10" converter but my trans went to 5500 on shifts , , the 1/8 speed and et was great but the top end pickup was only 21 as near the top of the track it was hard keeping more than 22psi and power would drop off, i was on 26" tires , 27s or 28s would have helped a little

 

[sweetv6]

my best pass see my sign

cp

 

[murphster]

cas V1 , 70mm throttle body on a precision 65 .....

so I might get to see if the huge i/c matters much

I was looking over some of the data from the Bob Dick IC test and it looks like while the CAS ICs have very good heat transfer, they still have a fairly good pressure drop. I think you ran a CAS V4 previously and didn't really see any gains over a dutt neck IC? We already know that with alky we don't see any drop off in performance from heat soak with a stock location intercooler. I don't think its a stretch to say that the heat transfer differences between ICs are somewhat negated by alky. And looking at the pressure drop data from the IC test, there's not much of a difference between the CAS ICs and a dutt neck IC. This could explain why you didn't see a performance difference between a dutt neck and CAS V4 IC when on alky, i.e. the better heat transfer from the CAS V4 didn't make a difference. Additionally, the stock turbo may not move enough air where there is a bottleneck flow-wise so the extra flow capacity wouldn't help. On a bigger turbo the flow capacity would probably make a difference though.

Even if the CAS V1 IC has the same pressure drop as a dutt neck IC, there is no doubt that it has better heat transfer. So even if the turbo is working just as hard, the air should be cooler entering the uppipe. It will be interesting to see if the alky negates this advantage or if there would be a performance increase as compared to a dutt neck IC on the stock turbo.

A good test would be a dutt neck IC compared to a IC with a low pressure drop on a stock turbo with alky. Another test would be to drop the IC altogether and just run a dual nozzle alky kit, although I assume the extra temps would overide the gains from minimal pressure drop, but who knows.

 

[Turbo6Smackdown]

That's what I was talkin' about. Better flow from the intercooler, not necessarily cooler temps. Heads, cam and IC HAVE to make a difference with the turbo. Easier flow, less boost required.

 

[Mr.Spool]

pacecarta,ed brewer's 11.3 pass on the stock turbo was on 26 inch tires,i spoke to him and he said the car couldn't pull the 28 inch tires.inmo the big intercooler is a waste when you have the alky,i think ed was in the 11.60 range before the dutt neck and a couple of other little tweaks

 

[pacecarta]

ive got 255/60-15 27" mickey dr's, mickey et drags 28x9-15 27.3", and the 28x10.5-15 28" that also grow a little over 100mph
so i can try them out and see ,
the boost is electronic and what i punch in is what it will run and i can run it harder at the bottom of the track .. and the fast logs everything so if it cant keep up I'll know

only thing i dont have which would be nice on this setup is a lockup converter that would help the 26" tire

 

[charlief1]

I'm not trying to confuse any one but here's the map of the stock turbo with notes included. It give you some idea but you can slide the map either way depending on what you do to increase your output. I needed these and Garret was nice enough to let me have coppies for my research. Hope this helps you some.:smile:

 

[bison]

I went 11.88 with a stock turbo back in 99. Stock intercooler with the neck mod and stock heads/cam. I had a do it yourself alky kit on there and i ran very tall slicks to keep the rpm down. Boost would spike to 25+ in 1st and was 23 or so on the gauge in 3rd. Timing was 24* if i remember correctly. Tall tires (Phoenix 28.5x9), hard launch and dump in a lot of alky. Alky will drop the charge air temps so you can take a turbo a lot further than you could without it.

 

[forcefed3.8's]

With 21lbs, the Cutlass ran 12.0's@111 with stock turbo, heads, cam, intercooler, unlocked converter, 30lbs injectors with a Red's 108 chip. With ported heads, 210/215 roller, Powerstroke intercooler, 60lber's, TT chip, stock unlocked converter still, it went 11.72@114 with 18psi. Stock wastegate wouldn't allow anymore. The wastegate rod was like 1" away from going on the puck, made no difference. The 12.0's were with 26" BFG DR's, 1.6 60's, the 11.7's were with 28x9 MT slicks, 1.5 60's.

 

[Turbo6Smackdown]

Heads, cam, and an intercooler only dropped 3 tenths off your score??? Hmmmmmm

 

[forcefed3.8's]

It just shows that a turbo will only push so much. The car might have picked up some if we put a spring on the wastegate. I think the back pressure was pushing open the wastegate. We put a TE63e on it, and it went 123 to 124 @ 20psi.
There are certain levels, where these exotic lastest and greatest parts don't make a difference, yet every 12 sec car on this board has to have them.