Rhitter Posted August 13, 2016 Share Posted August 13, 2016 If I had forged internals I'd go bigger than that. The Blouch Dom 1.5xtr is a pretty great all around package, and honestly is just as responsive as many TD05-18G setups I've driven, but with much, much higher flow capabilities. If bloch matched the Dom to legacy gt housing I would want it. The ability to throw on the stock intercooler to pass visual for Smog is pretty damn nice. My OBXT build Link to comment Share on other sites More sharing options...
fahr_side Posted August 13, 2016 Share Posted August 13, 2016 If bloch matched the Dom to legacy gt housing I would want it. The ability to throw on the stock intercooler to pass visual for Smog is pretty damn nice. The reason the 440XT is his biggest LGT format turbo is the puny stock intercooler footprint. Those bolt-on cooler like the Perrin and AVO aren't enough and the larger aftermarket ones can be used with STi-style turbos. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
Rhitter Posted August 13, 2016 Share Posted August 13, 2016 The reason the 440XT is his biggest LGT format turbo is the puny stock intercooler footprint. Those bolt-on cooler like the Perrin and AVO aren't enough and the larger aftermarket ones can be used with STi-style turbos. 100% agree. I am just complaining about CA CARB. DOM1.5 is or sure my dream set-up. Everyone only has amazing things to say about. If I had forged internals I'd go bigger than that. The Blouch Dom 1.5xtr is a pretty great all around package, and honestly is just as responsive as many TD05-18G setups I've driven, but with much, much higher flow capabilities. Now that I looked into it more (Brentuning) it really looks like a VF52 doesn't give up that much to an 18g (with similar supporting mods). Sort of seems like a waste of money to move from a VF52 to an 18g, should stick with that until I am ready to go bigger. My OBXT build Link to comment Share on other sites More sharing options...
fahr_side Posted August 14, 2016 Share Posted August 14, 2016 Now that I looked into it more (Brentuning) it really looks like a VF52 doesn't give up that much to an 18g (with similar supporting mods). Sort of seems like a waste of money to move from a VF52 to an 18g, should stick with that until I am ready to go bigger. The 18G will run away from a VF-52 at higher revs but it will work with the stock TMIC format if stealth is important. You can also run the 18G full chat on the stock intake. OTOH an 18G is pretty much the upper limit for what the stock motor can handle. Some live, some don't. The Dom needs more supporting mods but is about as responsive as the 18G and in my case did about 90whp more. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
xtea Posted August 14, 2016 Share Posted August 14, 2016 Sorry, I thought this was common usage. != means 'does not equal'. Boost threshold is the lowest rpm at which the available exhaust gas can spin the turbo fast enough to create meaningful boost pressure. Response is the rate at which boost rises for a given change in throttle input once the engine is already spinning faster than the boost threshold. It can be measured, but that's not what shop dynos are usually used for. To make this comparison meaningful you'd really have to run on the road, give very precise and repeatable throttle inputs, and then measure the time taken for boost to rise from A to B from given rpm points for both setups. Remember I'm a big Blouch fan myself and I am not looking to put them or their product down. I've seen those 8 vs. 10cm2 overlays myself and am very impressed with what they achieved. But, I still doubted the 10cm2 version would respond in the same way on the road. I have seen the results from for example the same GT2835R with both .64 and .85 housings. This is the same turbine the 1.5XTR uses and the same size compressor. Boost threshold between the two was almost identical, but on the track the smaller housing definitely had better throttle response and the larger one had an edge in power at high revs. On a shortish, tight track the car was much quicker on the smaller housing overall, though the top speed on the straight was lower. On the dyno the larger housing might show more torque when revs are held at that level for measurement or revs are slowly ramping up at the preset rate. On the track however, especially in the lower gears, revs rose so fast that the larger turbo didn't have time to spool fully and the car was in fact slower through the gear. In other words the smaller housing made the car quicker in the lower gears and held it back in higher ones, while the larger housing did the opposite. These tests were done with the exquisite TiAL housings btw, not some random garbage. I haven't had the opportunity to play with Blouch's 10cm2 housing but I doubt it's able to bend the laws of physics quite so far as to give it equal response to the 8cm2 version. If anyone has pump gas data that says otherwise I'll happily eat some crow and beg Blouch to sell me a bare housing! If I had access to E85 fuel I'd have been braver and bought the bigger snail. I think I know what you're saying. What we don't see on the graphs is time. So we can't see how responsive the turbo is because we can't see how quickly revs and boost are building. You're saying with 8 cm Rabbs climb higher faster and boost might build faster as well just not at the same RPM intervals as with the 10 cm house. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted August 15, 2016 Author Share Posted August 15, 2016 Fahr, are you saying the 18G is at the stock motor's limit on pump gas, or on E85? Link to comment Share on other sites More sharing options...
fahr_side Posted August 15, 2016 Share Posted August 15, 2016 Fahr, are you saying the 18G is at the stock motor's limit on pump gas, or on E85? Yes and no. You can run any turbo safely on the stock block by keeping the boost down and timing conservative. Much of the extra power seen on E85 tunes vs. pump gas is from being able to run higher boost without running into det. Regardless of fuel used, the stock head bolts will lift beyond 18psi or so, so that's a hard limit. Of course you get to tune to MBT on corn where you tune almost to the knock threshold on pump gas, so fewer pistons are broken on E85 than pump gas. So yeah, its probably as safe (or risky) doing say 350whp on corn as 320whp on pump gas on the stock block and you don't need to run larger than an 18G to get to those numbers. Not sure if that's what you were asking. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted August 15, 2016 Author Share Posted August 15, 2016 I've seen plenty of people running 22-23psi on E85 on 16G's and 18G's without issue, as well as 20psi on both on pump gas without lifting heads. Sure the studs have their limits, but I haven't really seen much issue with boost pressures in the low 20's. I mean what's safer, a Dom1.5xtr at 18psi on pump gas or a 16G on E85 at 22psi? You wouldn't need to ever worry about detonation on E85 at those pressure levels. Link to comment Share on other sites More sharing options...
fahr_side Posted August 15, 2016 Share Posted August 15, 2016 I think I know what you're saying. What we don't see on the graphs is time. So we can't see how responsive the turbo is because we can't see how quickly revs and boost are building. You're saying with 8 cm Rabbs climb higher faster and boost might build faster as well just not at the same RPM intervals as with the 10 cm house. Something like that. NSFW did some great work a few years showing how gear position doesn't really affect spool. We all know that the larger the turbo gets the more difference there is in spool rpm between gears. You might hit your boost target at 3k2rpm in 4th gear but in 1st that may become 4k5rpm. He showed that the time taken from going WOT to seeing target boost was essentially the same when measured in milliseconds and rpm ignored. It just usually takes a lot less time for engine revs to rise in the lower gears, while it takes the same time for the turbo to spool up. You don't see this as clearly on the dyno because the roller speed ramp rate is fixed by the operator. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
fahr_side Posted August 15, 2016 Share Posted August 15, 2016 I've seen plenty of people running 22-23psi on E85 on 16G's and 18G's without issue, as well as 20psi on both on pump gas without lifting heads. Sure the studs have their limits, but I haven't really seen much issue with boost pressures in the low 20's. I mean what's safer, a Dom1.5xtr at 18psi on pump gas or a 16G on E85 at 22psi? You wouldn't need to ever worry about detonation on E85 at those pressure levels. I wouldn't really agree it's safe running at 22psi on the stock head bolts. It's just a matter of time. I agree peak cylinder pressures are lower on corn than gas for the same boost pressure but does that make it okay to run at 4psi higher? I don't think so. Running the Dom at 18psi is a waste of a fine turbo. General rule of thumb is you'll get more from less on corn. If it were available to me I might have kept my 18G. I still suggest you go that way and start saving to build the motor to support the Dom at the pressures it shines at for your next move. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted August 15, 2016 Author Share Posted August 15, 2016 I think I'll go the ELH/keep 16G route. I really just want to get the car dyno tuned. I'm losing faith in my e-tune that I've been running for the last 20K. As far as I can tell it's safe, but it isn't really all that smooth. Link to comment Share on other sites More sharing options...
fahr_side Posted August 15, 2016 Share Posted August 15, 2016 That's a great setup for a DD and should last a good while. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted August 15, 2016 Author Share Posted August 15, 2016 How big is the difference between a dyno tune and e-tune? I've never had my car dyno tuned before. I'm wondering about the difference drivability wise? Link to comment Share on other sites More sharing options...
fahr_side Posted August 16, 2016 Share Posted August 16, 2016 In terms of power it can be a few percent. On bigger builds it can be a significant number. I like to finish all my dyno tunes with a session on the road to identify and solve any drivability issues, and polish boost control. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted August 16, 2016 Author Share Posted August 16, 2016 Should I go with a 38mm EWG or 44mm? If I am looking long term at running this with a larger turbo, in the 30R range. Link to comment Share on other sites More sharing options...
fahr_side Posted August 16, 2016 Share Posted August 16, 2016 Ideal wastegate size is more about target boost than turbo size. If you're running at lower boost (like 18psi until you build your motor) you need to wastegate more and this need a larger diameter gate. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted August 16, 2016 Author Share Posted August 16, 2016 Ok, I understand that. By the time I'm running a larger turbo I'll have a built motor and be running higher boost. Most people are telling me I do not need the 44mm unless I was running less than 15psi of boost though. I'm not going to be running a 30R at 15-20psi. Link to comment Share on other sites More sharing options...
MTBwrench Posted August 17, 2016 Share Posted August 17, 2016 How big is the difference between a dyno tune and e-tune? I've never had my car dyno tuned before. I'm wondering about the difference drivability wise? In my personal experience, it made a HUGE difference in the smoothness of power delivery, and that was with a simple VF46 stock rebuild at stage 2. My E-tune actually made more power, but my dyno tune felt considerably faster and power delivery was butter smooth. I doubt I'll ever do an e-tune again unless I have no other option. Nothing against E-Tuners, but when they can be there and feel how the car pulls, in person, it makes a difference. MTBwrench's Stage 3 5EAT #racewagon 266awhp/255awtq @17.5psi, Tuned By Graham of Boosted Performance Everyone knows what I taste like. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted August 17, 2016 Author Share Posted August 17, 2016 Yea I could absolutely see that. I only went with an e-tune because I knew I'd be changing things up again in the not so distant future, so didn't wanna pay the premium for a dyno tune. But I'm at a place this time around where after the next round of mods I plan to stay there for a solid 2 years or so, so I think it'll be absolutely worth it. Link to comment Share on other sites More sharing options...
quick4dr Posted August 22, 2016 Share Posted August 22, 2016 I will one day push my Dom 1.5xtr to about 22-24psi but at 19, on pump 93 she is a great DD, Mikeys tune is buttery smooth and about a month away from being 1yr DD on this set up. if I could get corn readily in my area I would go flex fuel in a heart beat. Also need to stretch my stock 126k block to about 140k before I can rebuild her proper. Link to comment Share on other sites More sharing options...
fahr_side Posted August 23, 2016 Share Posted August 23, 2016 Yea I could absolutely see that. I only went with an e-tune because I knew I'd be changing things up again in the not so distant future, so didn't wanna pay the premium for a dyno tune. In a hundred tunes I probably do two or three on the dyno and a similar number are e-tunes. Road tunes are by far the most popular option. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
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